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Guidance Document

Good practice guide for the use of BSI PAS 100 compost in landscape and regeneration

WRAP’s vision is a world without waste, where resources are used sustainably. We work with businesses and individuals to help them reap the benefits of reducing waste, develop sustainable products and use resources in an efficient way. Find out more at www.wrap.org.uk Written by: Edwards J, Petavratzi E, Robinson L and Walters C

Contents

1. Introduction ........................................................................... 12. Tools ..................................................................................... 7 3. Soil manufacture and habitat creation ...................................... 104. Housing and mixed use development ....................................... 145. Energy crops on brownfield land .............................................. 176. Sustainable urban drainage systems (SUDS) and green roofs ..... 217. Slope stabilisation and erosion control ...................................... 248. Recreation and sports turf ....................................................... 289. Landscape maintenance .......................................................... 3210. Bioremediation ..................................................................... 35Appendix – Mixing Ratios ............................................................ 38

Good practice guide for the use of BSI PAS 100 compost in landscape and regeneration 1

1. Introduction This guidance document aims to provide good practice advice on the use of Publicly Available Specification1 BSI PAS 100 compost in landscaping and regeneration applications and, in particular, for the following uses: Brownfield restoration and habitat establishment; Highways and waterways; Sustainable urban drainage systems (SUDS) and green roofs; Sports turf; and General landscaping. Agricultural land is not covered within this guidance document, the use of compost in agricultural land falls outside the scope of this study. The Introduction section of this Good Practice Guide provides an overview on compost; summarising the benefits and considerations associated with the use of BSI PAS 100 compost, outlining compost types and input materials, regulatory requirements and the different compost applications and landscaping sectors. The Tools section of the Good Practice Guide provides decision and support tools for assessing site suitability, site properties, and identifying suitable compost applications and land end uses. Sections 3 to 10 provide practical guidance and recommendations relevant to specific land end uses. A series of Technical Documents accompany this Good Practice Guide; these provide specific technical information on the following compost applications: Compost in soil improvement; Compost in topsoil manufacturing; Compost in soil amendment and surface treatment; and Compost in erosion control, sustainable urban drainage systems

(SUDS) and green roofs. The Good Practice Guide and accompanying Technical Documents can be accessed online through www.wrap.org.uk/landscapegpg.

What is compost?

Compost is the result of the organic breakdown of green and food waste, under controlled and monitored conditions. Compost is an important product to the landscaping industry and can provide various benefits in projects involving reclamation, restoration and the improvement of land. Compost is a source of organic matter and can improve the physical and chemical properties of the soil to which it is applied, enhance plant growth, stimulate biological activity and improve resistance to erosion. BSI PAS 100 compost is ideal because not only is it a rich source of nutrients, it is also quality assured and therefore reliable and consistent. WRAP has identified a number of producers of BSI PAS 100 compost2 spread across the UK.

Figure 1: Compost Pile, on A421 extension, Bedfordshire

http://www.wrap.org.uk/gpgfaqs/

http://www.wrap.org.uk/farming_growing_and_landscaping/reports_and_guidance/soil_improvement.html

http://www.wrap.org.uk/farming_growing_and_landscaping/reports_and_guidance/topsoil_manufacture.html

http://www.wrap.org.uk/farming_growing_and_landscaping/reports_and_guidance/surface_treatments.html

http://www.wrap.org.uk/farming_growing_and_landscaping/reports_and_guidance/erosion_control.html

http://www.wrap.org.uk/landscapegpg

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/faqs/

2 Good practice guide for the use of BSI PAS 100 compost in landscape and regeneration

Achieving the benefits of BSI PAS 100 compost use

To achieve these benefits, it is important to have compost supplied that meets the required specifications and is suitable for the intended end use. Compost performance is dependent on particle size; finer grades are most effectively used as a soil improver, within soil manufacturing or as top dressing, while coarser, woodier fractions provide effective and long-lasting mulch3. Therefore ensuring the supply of suitable material will determine the effectiveness of its application. Cost benefits associated with specific land end uses4,5,6 are discussed in more detail in Sections 3 to 10. Limitations

There are a number of considerations and limitations associated with the use of compost. These should be considered during the site investigation stage. For example, compost should not be applied to a site if7: there is a permanent groundwater table

within 1m of the surface; the site is within 20m of surface water

or 50m of a drinking water supply; and the site or part(s) of the site are subject

to regular flooding or inundation. However, BSI PAS 100 compost has been used close to water courses in sustainable urban drainage systems, compost socks, swales, reed beds, and permeable reactive barriers and is suitable and safe when used in these engineering solutions. Therefore, it is important to assess the site requirements and the impact of the compost on a site-by-site basis.

Why use compost?

Topsoil can be difficult and expensive to source and is a precious, finite resource. Therefore, compost offers a financially competitive and sustainable alternative to the importing of topsoil. BSI PAS 100 compost can be mixed with recycled inert materials such as surplus soil or crushed stone, existing low quality soils or be combined on-site with soil-forming materials. The inert material provides a consistent, stable material and the compost provides the nutrients and minerals required for root development8. The mixture of compost with existing indigenous soils can improve soil structure, reduce compaction in the surface layer, improve water holding capacity, improve soil drainage and significantly reduce the loss of nutrients into the groundwater. When incorporated into and applied onto soils, compost can act as a fertiliser and/or weed suppressant, which improves the soil’s physical properties. It contains nitrogen, phosphate, potash and other nutrients available for plant growth, helping to keep vegetation healthy and increasing nutrient take up. The benefits associated with the use of BSI PAS 100 compost are outlined in Table 1. Considerations

If the site is part of an environmental protection area, consultation with the relevant environmental protection bodies is essential. If the site is within 100m of a permanent dwelling a site-specific risk assessment should be conducted to understand the likely impact of the proposed site use on local residents; such as from noise and odour. High application rates of compost may result in phosphorus and potassium release that is greater than plant requirements and has therefore the potential to leach into drainage water. Ensuring the correct application rates and right type of vegetation are in use, as well as establishing monitoring procedures will effectively mitigate this risk and be more cost effective. Other site-specific impacts may be present and they should be assessed and investigated on a case by case basis to reduce the risks associated with compost application and minimise the barriers to effectiveness. These may be relevant to the composition of compost and soil forming materials, presence of contamination on site, the topography of the site, the properties of the receiving substrate and proximity to surface and groundwater or handling and application practices. Any risks should be considered and weighed against potential benefits7.


Table 1 Benefits associated with the use of BSI PAS 100 Compost in landscape and regeneration projects Benefit type Benefits Physical Compost can lower the bulk density of soils which in turn will improve soil structure leading

to greater workability and significantly easier cultivation, better drainage, and an improvement in aeration and root penetration (particularly in clay soils). The water holding capacity and aggregate stability of light soils can be improved with compost, and thus reduce the risk of wind erosion during dry periods. The use of compost mulches can act as a protective layer to the soil surface, which reduces weeds, retains moisture and impedes erosion. Improved soil structure is important particularly in areas with high levels of pedestrian traffic, such as in coastal paths or areas close to water courses. The use of compost darkens the soil leading to an increase in the soil temperature that can enhance germination of seeds and plant establishment especially during cold weather conditions.

Chemical and biological

Compost provides slow-release plant nutrients, such as nitrogen, phosphate and potash as well as minor and trace elements. The readily available nutrients can assist vegetation establishment and promote plant growth. Stabilisation of soil pH leading to increased soil buffering capacity, reduced environmental effects and reduced mobility of certain contaminants (particularly effective in acidic soils). The cation exchange capacity of soils can be increased leading to a decreased nutrient loss to leaching. Compost provides beneficial micro-organisms that may contribute towards the suppression of some common plant diseases. Compost can reduce weed establishment and growth, when applied as mulch.

Ecological and environmental

The use of BSI PAS 100 compost in landscape and regeneration projects promotes habitat creation. Poor soils in brownfield sites may provide opportunities for carbon sequestration. The most carbon-depleted soils offer the greatest opportunity to absorb and sequester carbon9. Adding compost to soil will increase the population of soil invertebrates and this, in turn, will increase bird populations and biodiversity. The production and use of green and food derived compost reduces the amount of waste sent to landfill.

Economic Eliminated or reduced costs associated with excavating, transporting and disposing of poor quality soil and other existing site materials and the subsequent purchase of topsoil. Reduced plant fertiliser costs through compost’s provision of slow-release nutrients. Reduced need for herbicides, particularly when applied as mulch. Compost can aid the growth rate and survival of plants, saving re-planting costs and maximising profit if used for energy crop production. Reduced irrigation costs due to the improved water retention properties of the soil. Compost improves the structure of the soil allowing machines to work with less effort, thus reducing the need for equipment maintenance and repair. This reduces cultivation costs.


Control measures

BSI PAS 100 includes controls such as the Hazard Analysis and Critical Control Point (HACCP) measures, to ensure that risks of adverse impacts to the environment and human health are minimised. The BSI PAS100 composting process eliminates most plant and human pathogens that may be present in the feedstock, and quality and regulatory measures are in place to ensure that it is a safe and reliable material to use. Compliance with BSI PAS 100 provides strict control over chemical and physical contaminants likely to be present in compost, for example arsenic, cadmium, copper, lead, mercury, nickel, selenium, zinc, glass and plastic7. Soil forming materials

Soil profiles used in soil manufacturing often comprise green and/or food derived compost mixed with in situ or imported soils and depending on the circumstances, other organic and inorganic materials may be added. Other organic and inorganic materials could be used in soil-forming mixtures such as paper mill crumb, biosolids, waste soils, rock dust, topsoil, in situ soils and others. Guidance on other organic materials is given elsewhere10.

Compost types and input materials

Green and food derived composts are used in landscape and regeneration projects. Green compost is solely derived from garden waste and comes from sources such as domestic gardens, municipal parks and recreational areas, and is collected separately from other waste streams. This compost is usually produced in open windrows. Food derived compost contains a mixture of garden and food waste collected separately from other waste streams from households and businesses. This compost is produced in enclosed in-vessel systems and must be compliant with Animal By-Products Regulations (ABPR), as well as the relevant waste legislation. The end result of the two composting processes is a product which is safe and reliable with high organic matter content and significant quantities of nutrients7. Both green and food derived composts can be assessed to comply with the BSI PAS 100 standard for quality compost1. Building upon the BSI PAS100 certification, the Quality Protocol was launched in May 2007. Applicable in England and Wales only, it provides a clear framework for the production and supply of quality compost. It clarifies which waste materials can be used in quality compost production and reinforces traceability throughout the production process by ensuring accurate record keeping. Compost which complies with the Quality Protocol is no longer classed as a waste. This Guide provides advice on the use of BSI PAS 100 compost, therefore the information included here should not be considered as appropriate for the application of other compost types and compost-like outputs that do not comply with BSI PAS 100 specification. BSI PAS 100 specifies that compost shall be of a friable texture without excessive moisture, and shall not exceed limits on stones, weed propagules, and physical and chemical contaminants. The product shall not contain substances toxic to plants, nor shall it possess objectionable odours1,6. Digested materials complying with the requirements of the BSI PAS 110 specification can also be applied to land for restoration and reclamation, and guidance on these materials is given elsewhere10.


Regulatory requirements

The EU Landfill Directive, the UK landfill tax system and the Landfill Allowance Trading Scheme are the principal policies aimed at reducing the quantity of biodegradable waste sent to landfill in the UK and they have supported the use of compost and other organic materials in landscape and regeneration projects. The application of BSI PAS 100 compost to land is considered a reuse of materials. The application of compost to degraded land that does not meet the Quality Protocol criteria, as part of a land reclamation programme, is considered a waste operation in England and Wales and has been regulated through the Environmental Permitting Regulations (EPR)11. New exemptions and Standard Rules Permits for land spreading and land reclamation have been in force since April 2010. This allows for the land spreading of BSI PAS 100 compost and other listed materials. These regulations should be taken into careful consideration when planning any such activities. Certain operations will require a Standard Permit and further information relevant to the application of compost on land can be found in the Standard Rules covering activities related to the Recovery or use of waste on land11. Certain operations will not require a Standard Permit, but they will need to be registered with the new Waste Exemption system13. The rules that apply to these exemptions and the activities covered should be carefully reviewed prior to application. Further information can be retrieved from the Environment Agency website12,13. The European Water Framework Directive (2000/60/EC)14 and associated Groundwater Directive (2006/118/EC)15 represent the principal legislation for the protection of the aquatic environment. The use of compost in landscape projects and regeneration should cause minimal impact on the aquatic environment. The Water Framework Directive and Groundwater Directive have only limited relevance to the use of recycled organic materials in land reclamation and this will generally be in the case of large projects.7 The European Nitrates Directive aims to minimise the impact of diffuse nitrate pollution and improve or maintain the ecological status of surface water in line with the Water Framework Directive. The European Nitrates Directive16 currently sets no designated Nitrate Vulnerable Zones (NVZ) restrictions on non-agricultural land as part of a land reclamation project. In many cases during land reclamation there are practical reasons for applying greater quantities of nitrogen, in particular where highly degraded soils that require improvement are present. The nutrient content of compost is less prone to leaching than inorganic fertilisers7.

Quality compost across the UK

BSI PAS 100 sets the criteria for the production of quality compost that can be used in land reclamation and provides the assurance required to users. In Scotland, compost produced in compliance with BSI PAS 100 is considered as fully recovered and therefore is no longer regarded as a waste material, provided that a secure market for this material exists. In England, Wales and Northern Ireland compost must also comply with the relevant Quality Protocol to be fully recovered and not considered as waste7. The Compost specifications for the landscape industry recommend that additional requirements to the BSI PAS 100 criteria should be met for different end uses in order to ensure that the product is fit-for purpose6. These are summarised in the accompanying Technical Documents. The Compost specifications for the landscape industry are currently under review and a new version will be published shortly.

Figure 2: Wildflowers establishment after soil manufacturing - Whitehaven


Brownfield regeneration

BSI PAS 100 compost can improve existing poor quality soils affected by sealing, compaction and, possibly, contamination. It can also be used where topsoil may not be present due to previous activity. The addition of organic matter in a manufactured soil will improve the structure and quality of the existing material7. Highways and waterways

BSI PAS 100 compost can be used to control soil erosion for slope stabilisation, in topsoil manufacture and for vegetation establishment. The use of BSI PAS 100 compost in highway batters increases the recycled content of road schemes and helps to meet sustainability objectives. Sustainable urban drainage systems (SUDS)

The construction of green roofs and other SUDS can utilise BSI PAS 100 compost for vegetation establishment; current research examines the use of compost in the substrate layer of green roofs. Sports and leisure

BSI PAS 100 compost can be used in sports pitches to promote root zone and turf establishment and as a top dressing agent. General landscape applications

Compost can be used in various landscape projects including ornamental gardens. Low maintenance, cost effectiveness, weather resistance and an aesthetically pleasing and safe environment are some of the essential qualities of products used in landscape projects. BSI PAS 100 compost can be applied for soil improvement, in vegetation establishment, topsoil manufacturing, in maintenance activities and mulching.

Compost applications

Compost can be used in various landscaping and regeneration projects. Compost is suitable for use in the regeneration of brownfield sites intended for a variety of end uses such as energy crop production, grassland and woodland establishment, sports turf establishment and the creation of housing and mixed use developments. Compost can be used in conjunction with engineering solutions, such as compost socks to control erosion, and in SUDS, to help reduce the risks and severity of downstream flooding. BSI PAS 100 compost can also be applied during the maintenance of existing sites as a surface treatment, typically as a top dressing or as mulch. This guide has been structured to provide good practice advice for a variety of land end uses that cover the reported sectors. Individual sections on land end uses provide further detailed information. The Technical Documents accompanying this Guide provide further details about compost applications. The way compost applications, land end uses and sectors are related is summarised in Table 2.

Table 2: Land end uses, compost applications and sectors

Good Practice Guide

Section Technical Document on the use of compost in: So

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Soil Improvement

Topsoil Manufacturing

Erosion Control, Sustainable Urban Drainage (SUDS) and Green Roofs

Soil Amendment and Surface Treatment





http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/soil_manufacture_and_habitat_creation/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/housing_and_mixed_use_development/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/energy_crop_production/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/suds_and_green_roofs/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/slope_stabilisation/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/recreation_and_sports_turf/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/landscape_maintenance/

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/bioremediation/


2. Tools

Types of Survey

A soil survey will help to identify the presence and quality of existing suitable site material that can be used with compost to create a useable soil. If soil forming materials are present, and required for development, the site should be sampled according to standard methods. The site should be split into areas which are obviously different (for example due to the appearance of the material, or site topography) and sampled separately. The number of samples and parameters to be tested depends on both history and intended use. A risk assessment should be conducted during site investigation activities to understand the level of need for a buffer zone and to understand the odour and noise implications of the project. Typical procedures within the risk assessment activity may include the identification of hazards, receptors and pathways, together with an assessment of the likelihood of this exposure pathway occurring, the scale of the impact and an overall assessment of risk7. Ecological surveys are often used as baseline data and can be used to compare with further similar surveys conducted the next year or a number of years later. Ecological surveys usually consist of a species list, habitat map and site description. A habitat survey map shows the extent and types of habitat present, this may be created using quadrats to record plant species present, abundances and percentage cover. Statistical analysis can be used to compare data sets and repeat surveys can be carried out at selected intervals to compare the relative success of species germination and growth.

Site investigation

Sufficiently qualified individuals or organisations should carry out the site investigation with a view to the final site use to identify potential areas of contamination, and which areas will benefit from compost application and to what degree. The tools provided in this section include a decision tree to help identify the requirement for compost and signpost to the relevant technical document, and a checklist summarising the information required.

Figure 3: Wildflower establishment


Decision tool

Is the soil on site contaminated?

Define your objectives

What are the planned objectives for this site? (for example, reclamation, maintenance of existing vegetation on

site, improving brownfield areas)

Is an engineering solution required?

(Such as green roofs, slope stabilisation or erosion control)

Refer to Compost in Soil Amendment

and Surface Treatment Technical Document

Refer to Compost in Erosion Control, Sustainable Urban Drainage

Systems and Green Roofs Technical Document

Identify relevant data/ Information from

Site investigation

Improve soil

Manufacture topsoil

Refer to Compost in Soil Improvement

Technical Document

Is there sufficient soil forming material on site?

Can economically viable compost and other soil forming materials

be sourced locally?

Import compost and soil forming materials

Yes

No

No

Import soil

No

Yes Refer to Compost in Topsoil

Manufacturing Technical Document

Is the requisite vegetation

already established?

Assess the use of compost for bioremediation

Yes

No

Yes

Is the soil of sufficient quality?

Is there sufficient quantity of soil on site?

No

Yes

Maintain soil Yes

No

No






Checklist

The following checklist provides a number of items to be considered prior to, during and after compost application.

Prior to compost application

Information likely to be present from geotechnical/environmental investigation

Initial site suitability assessment with identified areas for compost application

Consultation with relevant authorities and stakeholders

Any data regarding contamination on site

Soil profile information readily available

Information on close proximity and likelihood to contaminant sources, pathways, receptors

Susceptibility to flooding

Topography, geomorphology, geology etc. data

Any opportunities and limitations from initial studies, such as habitats to retain/enhance/remove, assessment of nature conservation significance (if relevant, plant habitats present, other)

Weather patterns and climate

Any visibility and aesthetic issues

Information likely not to be present

Soil properties (chemical + physical) Key to consider: Nutrients (K, P, N, Ca, Mg, C:N ratio), bulk density, texture, cation exchange capacity (CEC), organic matter, pH, electrical conductivity, compaction, physical and chemical contamination

Effect of compost application on mobility of contamination

Compost quantity requirements

Soil profile and compost incorporation depth

If soil-forming materials are required, then the following should be considered: availability, type and properties (equally for imported or/and in situ materials)

Assess the need for an Environmental Permit or exemption, if waste material is to be used on site

When handling soil, consider the need for a soil management plan – identify if soil handling and storage have been included in the planning permission

Identify local sources of BSI PAS 100 compost and other soil-forming materials required on-site; assess their economic viability

Quality control during application

Verify that delivered compost meets BSI PAS 100 specification and is suitable for intended use

Confirm compost application rates and mixing ratios, depth of incorporation, application procedures, machinery and so on

For topsoil manufacture ensure that a quality management scheme for production is in place

Post application checklist

Confirm improvement/soil profile depth

Check soil properties against baseline values (values recorded prior to compost application)

Monitoring procedures/plan in place

Assess vegetation growth/health/others

Contaminants – potential to leaching and toxicity


3. Soil manufacture and habitat creation

Cost benefits

At Lambton former coke works the use of on-site materials, in conjunction with BSI PAS 100 compost and paper mill crumb resulted in an estimated cost saving of £434,00017.

Figure 4: Tree planting at Lambton Former Coke Works Similarly, at Dalquhandy open cast coal site the manufacturing of soil in situ with the importation of compost, even at £12 per tonne, resulted in substantial savings of £110,000 per hectare when compared with importing topsoil18. At Cronton colliery19 BSI PAS 100 compost has successfully been used on bare colliery spoil as a soil improver, to establish semi-natural grassland. The trials demonstrated that this is a cost effective approach with savings of approximately 88% to importing subsoil. An example of the costs associated with the use of compost at different application rates as a soil improver in Dunbar quarry20 is given in Table 3. Many of these cost benefits are case specific and they depend on landfill costs, availability of materials in required quantities and cost of imported materials.

BSI PAS 100 green and food derived compost can be used in the creation of woodlands and grasslands. Compost can be used to enhance vegetation and to promote habitat restoration and development. Compost has been used successfully in various brownfield regeneration projects in soil manufacturing, as a soil improver and as a top dressing agent. Compost socks and compost mulch have been used to control erosion in wetlands and in embankment construction. The purpose of topsoil manufacturing is to create an effective soil for the establishment of vegetation. The term topsoil manufacturing, as used in this document refers, to the blending of soils available on site and potentially other organic or inorganic materials with BSI PAS 100 compost to produce a soil that suits the requirements of the site and provides the same functions as topsoil. Benefits and risks

Environmental benefits from the use of compost in woodland and grassland establishment include the use of in situ soils, compost and other organic and inorganic (inert) resources reducing the generation of waste. Compost can promote habitat development such as amenity grassland, wildflower habitats, trees and woodlands.

Table 3: Cost of using compost as part of the standard restoration process used at Dunbar quarry (2007)

Input - BSI PAS 100 Compost (0 – 20mm) applied with topsoil for soil improvement Cost

Depth of application (cm)

Compost (%)

Rate £/ha

25 5 125 m3/ha (64 t/ha) 1460

25 10 250 m3/ha (128 t/ha) 2420

25 15 375 m3/ha (191 t/ha) 3365

25 20 500 m3/ha (255 t/ha) 4325

25 25 625 m3/ha (319 t/ha) 5285

40 5 200 m3/ha (102 t/ha) 2130

40 10 400 m3/ha (204 t/ha) 3660 aCompost was BSI PAS 100, 0 – 20 mm grade from Scottish Water, costing £15/tonne in total (based on a cost of £7/tonne + £7/tonne for haulage + £1/tonne for spreading). The cost of incorporation was approximately £500/ha for incorporation at 25 cm and 600/ha for incorporation at 40 cm. bAbove costs are in addition to those associated with the standard land restoration practice at Lafarge’s Dunbar quarry (i.e. no compost or fertiliser applied along with the topsoil/subsoil mix). Spreading of topsoil/subsoil mix costs approximately £8400/ha.

www.wrap.org.uk/gpghabitiat

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/soil_manufacture_and_habitat_creation/


Application of compost

The amount of compost that is appropriate to use for a site will depend on the properties of the compost to be applied, the quality of the soil forming material and the intended land end use of the reclamation project. Application rates will be site specific and influenced by factors such as the topography of a site, the soil infiltration rate, weather conditions prior to application and future weather patterns21. Some guideline values are shown in Table 4.

Table 4: Typical rates of application for different end uses of land

Goal of reclamation

Sub categories

Typical maximum application rate1 (t/ha)

Notes

Habitat establishment amenity land

50-100 Plant growth trials are recommended to ensure that nutrient levels are not excessive for the intended purpose

Soil formation

Landfill cap 100-5002 The maximum application rate will vary depending on the condition of the land and contaminant concentration in both the organic amendment and the soil

Colliery spoil restoration

1 The application rate of organic materials with low dry solids content (<25%) should be at the lower end of the range shown depending on site-specific conditions. 2 Depending on site-specific environmental conditions, particularly in the case of colliery spoil, the maximum application rate may need to be higher than 500 tonnes per hectare, depending on the condition of the land, soil pH and the quality of the compost and other organic material(s) to be used. Application rates in excess of 500 tonnes per hectare would need to be justified to the environmental regulator and approved in advance. The mixing ratios of compost with other soil forming materials depend on the site characteristics and needs for organic amendment and also on the planned end use. Overall, compost in the soil forming mixtures has been trialled at percentages (by volume) ranging from 5 to 50%. The use of compost at rates higher than 25% has not provided substantial benefits to soil properties and vegetation growth24. A detailed list of mixing ratios used in past trials and for different soil-forming materials and end uses, including woodlands and grasslands, is given in the Appendix. The vegetation type and site characteristics should be considered when choosing the depth of application. For example, at Cross Lane, for woodland tree planting, a depth of 1m was used, for shrub species a depth of 0.75m, whereas for meadow grassland a depth of 0.5m was set.

Site investigation and sampling guidance

A checklist covering aspects of site investigation required during the identification of a suitable site and prior to the application of compost has been presented in Section 2. When planning for restoration/reclamation of a site using in situ materials, it is critical to investigate the availability of soil reserves. The following should be taken into consideration when planning for a woodland and grassland restoration project17:

soil types and volumes needed to achieve the intended landscaping;

soils and soil making materials present on the site; and

procedures needed to produce the required soils

Figure 5: Manufacturing soil on site Application methods

The use of different application methods, for instance, using different depth profiles or the inclusion of rotavation, can provide significant differences to the soil properties and plant establishment22. For example, the depth of incorporation of compost with the soil-forming material to manufacture soil is much deeper, compared to the use of compost for soil improvement.


Case studies

Case study Description

Ayrshire

Woodland establishment on restored land using PAS100 and recycled minerals

The project examines the use of quality compost with or without additional recycled minerals (rock dust) for the redevelopment of land. Two contrasting sites have been used for this work: a restored quarry in the village of Drongon; and an active restoration site at the edge of Shewalton landfill (mineral soils), near Irvine.

Packington, Midlands

Manufactured soils using canal dredgings (sediment) and green compost

This project is aiming to provide the information required to develop a protocol for the manufacture of BS 3882: 2007 quality soils from dredgings and compost materials. The trial takes place at a former landfill site.

Cronton Colliery, Knowsley

Restoring former colliery with wildflower habitats

A trial using BSI PAS 100 compost was undertaken on the former Cronton Colliery site in Merseyside. BSI PAS 100 green compost was mixed with the spoil to establish a wildflower grassland habitat.

Damside, Scotland

Soil amelioration on former open cast coal sites

This project was designed to assess the effect of applying BSI PAS 100 compost on a mixture of indigenous stony spoil and subsoil.

The plants to be used on a site location should be carefully selected to match the soil conditions. For woodland establishment the choice of tree species must be carefully considered, as the nutrient demand varies between different species. Some trees, such as, alders and other nitrogen fixing species can establish better than others on nutrient deficient sites; therefore, they will require lower application rates of compost21. Further technical advice and guidance is given in the Compost in Topsoil Manufacturing and Compost in Soil Improvement technical documents accompanying this Good Practice Guide and in the Compost Specifications for the Landscape Industry6.

Figure 6: Tree planting at Broughton Craggs

Soil preparation is essential prior to any compost or soil forming material application. This usually includes soil cultivation to some extent. If the site is predominantly made up of subsoil, deep tillage or ripping may be necessary to relieve compaction below the topsoil layer. Compost used for soil improvement is commonly spread over the treatment area and subsequently incorporated into the soil. The material should be incorporated into the soil as soon as possible after application to a maximum depth of 0.4m. Some adverse impacts that were identified through various WRAP trailblazer projects are summarised in Table 5. These barriers are case specific and their presence will depend upon the nature of the soils, the site characteristics and the land end use.

Table 5: Case specific barriers from WRAP trailblazer projects

Barrier Comment

Compost mulch results in high biomass per unit area

Royal Ordnance Chorley & Cross Lane, Wirral 23 The use of compost mulch produced a highly fertile substrate. However the high biomass per unit area created inter-specific competition at both sites causing a reduction in overall species richness of the plant community. Identifying the nutrient requirements at an early stage could eliminate this problem.

High application rates of compost

Greenoakhill landfill site24 Increasing compost addition from 25 to 50% by volume resulted in excessive nutrient concentrations, excessive soft growth of trees, wind rocking and stem damage of trees, excessive weed growth with competition for moisture and increased costs for labour and weed killer. The optimum compost application for this particular site was identified as being between 15 – 20% by volume.





Dalquhandy Open Cast Coal Site

Establishment of amenity grass on shale subsoils

BSI PAS 100 green compost was applied on indigenous shale subsoil (restored ground from open cast coal extraction). A high-value grass sward was established where it had not been possible to do so before.

Dunbar, SE Scotland

The effect of green compost on the establishment of rough grazing, arable grazing & amenity trees on a restored limestone quarry

Lafarge’s Dunbar quarry is the first in the UK to test the potential for using BSI PAS 100 quality compost in its ongoing land restoration programme. This project aimed to determine the economic viability of using BSI PAS 100 quality compost in restoring land for amenity and agricultural purposes.

Falkirk, Scotland

Establishment of wildflowers on soil platforms at a housing development using BSI PAS 100 compost

A trial at Redding Park, near Falkirk was established to investigate the suitability of using BSI PAS 100 compost to establish wildflowers and limit the need for expensive importation of topsoil when dealing with degraded brownfield sites.

Greenoakhill, Scotland

Restoration of a former landfill site to form a woodland and meadow

This project assesses the benefits of using BSI PAS 100 compost and on-site soil forming materials to create replacement topsoil at a former sand and gravel quarry.

Lambton, County Durham

Establishment of woodland in former coke works using BSI PAS 100 compost and paper mill crumb

Redevelopment of the former Lambton Cokeworks site in County Durham was conducted using a mixture of on-site materials, BSI PAS 100 compost and paper mill crumb. The new soil profile successfully supported tree and grass growth whilst offering savings of around £1.2m over more conventional restoration approaches.

North Somerset

Compost mulch proves its worth in council tree planting scheme

A 12-month trial was carried out on a municipal tree planting scheme in North Somerset. It has found that quality compost mulch can significantly reduce weed cover and enhance tree growth. Compost was applied as mulch, as a soil amendment or as a combination of the two.

Newtownhamilton, Northern Ireland

MOD and Defence Estates demonstrate the benefits of using quality compost to improve soils in Northern Ireland

The MOD and Defence Estates worked with WRAP to investigate and demonstrate the use of quality compost to improve soils in Northern Ireland. BSI PAS 100 quality compost was spread and incorporated into the soil. Early results showed that the seed germinated well and grass was established quickly.

Chorley and Cross Lane, Merseyside

Development of vegetation communities on manufactured soils at Royal Ordnance Chorley (Buckshaw Village) and Cross Lane

A partnership was formed to deliver the joint Trailblazer projects at Cross Lane Tip, Wirral and at the former Royal Ordnance Facility, Chorley, Lancashire. The aim of this work was to assess the beneficial use of BSI PAS 100 green compost as a component of soil manufacture in the creation of sustainable grassland landscapes.

Whitehaven, Cumbria

Creating wildflower meadows on the Rhodia chemical works site

This trial at a former chemical production site in Cumbria examines various mixes of topsoil, green and food derived compost, wool rich shred, quarry waste and screened brick waste. Their effect on wildflower establishment and growth have been measured.

Eden Project, Cornwall

Making the garden of Eden with recycled products

Compost produced from garden trimmings such as grass cuttings, prunings and leaves, and mulch made from recycled woodchip was mixed with existing mine wastes to manufacture 85,000 tonnes of soil during the development of the Eden Project on a 15 hectare former china clay quarry site in Cornwall.

Forgemasters , Sheffield

Award winning landscaping in Sheffield’s Forgemasters steel works using PAS100 compost

A SUDS landscape scheme in a former carpark within Forgemasters (steel works) was established in 2009. The scheme included the planting of young, ‘standard’ trees of mixed species and the planting of ground cover plants. Subsoil imported from another area within the River Don works was used to create the contoured design. The topsoil was mixed with compost to provide a planting medium.


4. Housing and mixed use development

From steelworks to green space, Ebbw Vale

BSI PAS 100 compost has been mixed with colliery shale to produce topsoil for use on a former steel works site in Ebbw Vale25. The Ebbw Vale site had a number of limitations, primarily due to previous land use. Investigations confirmed that quality green compost improved the cohesion of the basic steel slag and colliery spoil when applied at a ratio of 4:10 (compost to soil).

Figure 7: Ebbw Vale Findings from soil manufacture and bioremediation trials at Ebbw Vale to create urban green space on land previously used as steel works confirmed that BSI PAS 100 quality green compost can play an important and successful role in the effective decontamination and restoration of large scale brownfield sites, and make significant cost savings in the process. When compared to importing topsoil, using BSI PAS 100 compost to manufacture topsoil saved Blaenau Gwent County Council £450,000 – or £15/m225. The project also showed that the use of compost-based manufactured soils provides longer term cost benefits, such as reduced replacement costs for plants, with less of them being affected by drought and weeds, particularly during early establishment.

BSI PAS 100 green and food derived compost can be used in the landscaping of housing and mixed use developments. The application of compost can enhance vegetation establishment and growth, help to remediate contaminated brownfield land, and help to improve the soil’s water holding capacity. There is a wealth of evidence that demonstrates that compost is a suitable material for topsoil manufacture, soil improvement and soil amendment in the landscaping of housing and mixed use development, particularly on brownfield land. Quality compost offers a financially competitive and sustainable alternative to the importing of topsoil. It reduces the need of herbicides and other inorganic fertilisers as the material can be used to encourage the improvement of existing low quality soils or be combined on site with soil-forming materials to make topsoil. Applied as mulch, compost can suppress weed growth and increase soil nutrient content. Benefits

There are many benefits associated with the application of BSI PAS 100 compost, as detailed in the Introduction. Additionally, quality compost application provides specific benefits to housing and mixed use development applications. These include: reduced costs of importing topsoil and disposal of subsoil and

other soil forming materials to landfill. WRAP has developed guidance on ‘Designing out Waste’ for both buildings26 and civil engineering27 that can assist to optimise the use of materials and to reduce disposal to landfill;

reduced risk of slope erosion, particularly on subsoil consisting of basic steel slag and colliery spoil where compost improves the cohesion and stability of the materials25; and

potential for carbon sequestration in organically poor brownfield soils when existing site materials are blended with a carbon rich compost source.

Financial benefits

The use of BSI PAS 100 compost on housing and mixed use developments has been shown to have financial benefits when compared to traditional materials used for topsoil manufacture, site remediation, soil improvement and soil fertilisation. Through the application of BSI PAS 100 compost with existing site materials, the 265 hectare former munitions factory at Chorley has been transformed into the village of Buckshaw. It now comprises light industry, residential housing and large areas of public space28.

www.wrap.org.uk/gpghousing




The applied compost not only supported rapid plant establishment and therefore increased infiltration and reduced run-off, but also led to wider regeneration of the site. It has been calculated that to manufacture one tonne of soil, by reusing and mixing existing on site materials with BSI PAS 100 compost, costs £5.08 compared to £15.07 for landfill disposal of subsoil and importing a tonne of topsoil. Over the course of the project, cost savings of more than £300,000 have been realised. Table 6 provides a breakdown of the cost of producing new soil using existing site materials and BSI PAS 100 compost. Also it provides a comparison between three methods; disposing of the existing subsoil and importing virgin topsoil, recycling the existing subsoil and importing virgin topsoil and manufacturing soil with compost and site won material.

Table 6: Economic appraisal of on site soil manufacture at a former munitions factory, Chorley (2009)

Activity Cost (£)

16,055t of BSI PAS 100 compost, purchase and haulage £6.60/t

106,020

20,870t of subsoil to landfill 0

Handling costs for receiving compost, moving subsoil to mixing location and blending compost/subsoil (based on actual operational costs)

81,545

Total cost to manufacture 36,925t of soil 187,565

Cost per tonne of soil ready for use 5.08

Table 7: Cost comparison of three topsoil options

Cost per tonne of soil

Landfill disposal and import topsoil

Recycle and import topsoil

Reuse soil and create topsoil

(£) 15.07 12.57 5.08


The amount of compost that is appropriate for a site will depend on the properties of the compost to be applied, the quality of the soil forming material available on site or imported and the intended land end use. However, WRAP trials have shown compost to be effective when applied within soil manufacturing where soils are depleted, as a soil improver where the existing soils have low nutrient content and poor structure and also as a mulch/fertiliser on housing and mixed use development. Other site won materials, such as glacial till, steel slag and gritstone fines can be blended with compost, thereby ensuring the reuse, rather than disposal, of on-site material. Trials confirmed that the addition of compost at rates with higher ratios produced diminishing returns, and actually became counter productive when at a 6:10 ratio (compost to soil).

Housing development – Stirling, North Lanarkshire, Scotland

Topsoil, made from BSI PAS 100 compost was mixed with sandy loam at a 2:1 ratio (compost to soil) and was spread, in stages, across a six-acre housing development in Stirling, Scotland at a 150mm thickness to help promote long-lasting plant and turf growth in front and back gardens, as well as in public areas29. The topsoil was assessed against the relevant specification for topsoil (BS3882:2007) and was found to be equivalent to the premium grade available on the market. It was also assessed against the CLEA (Contaminated Land Exposure Assessment) guidance and was found to be more than satisfactory. Good results were evident after just two weeks, with the imported turf successfully establishing with minimal watering29.

Figure 8: Slope trial for a housing development, Redding Park, Falkirk Redding Park, near Falkirk,

The Redding Park development is built on a brownfield site which has been subject to the removal of topsoil by past and current development activities. A trial was conducted on the site to examine the suitability of using BSI PAS 100 compost as a means of limiting the need for the importation of top soil. The trial involved addition of different rates of compost to a housing platform seeded with grasses and wildflowers.


Case studies


Buckshaw, Merseyside

Royal Ordnance Munitions Factory, Chorley transformed into the village of Buckshaw

A 265 hectare former munitions factory site was transformed into a village, including light industry, residential housing and large areas of public space. Application of quality compost supported rapid plant establishment and therefore increased infiltration and reduced run-off. The use of compost in the wider regeneration of the site highlighted significant economic advantages, leading to savings of around £300,000.

Ebbw Vale

From steelworks to green space

The 90 hectare Corus Tinplate Works site in Ebbw Vale in Gwent, South Wales, is one of the largest regeneration schemes in the UK. The land is being transformed into a mixed use development consisting of new rail infrastructure, education and healthcare facilities. BSI PAS 100 compost was mixed with the existing colliery shale, steel slag and gritstone fines to produce a medium for vegetation establishment and growth, erosion control and also decontamination of the site.

Falkirk, Scotland

Establishment of wildflowers on soil platforms at a housing development

A trial at Redding Park, near Falkirk was established to investigate the suitability of using BSI PAS 100 compost to establish wildflowers and limit the need for expensive importation of topsoil when dealing with degraded brownfield sites.

North Lanarkshire

Going ‘green’ with compost reaps rewards for Scottish housing developer

Topsoil, made from quality compost mixed with sandy loam was used at this housing development in North Lanarkshire. It was spread at 150mm thickness across the six acre development to promote long-lasting plant and turf growth in gardens and public areas.

Raploch, Scotland

The use of compost to manufacture topsoil for brownfield regeneration at Raploch

Raploch is a typical re-development site on brownfield land in Stirling, formerly occupied by a housing estate with associated infrastructure, gardens and backyards. A trial took place to demonstrate the beneficial effects of using locally produced quality compost together with on-site soil forming materials to manufacture replacement topsoil.

Ravenscraig, Scotland

Soil manufacture with compost and steel furnace slag for landscaping the former Ravenscraig steelworks.

Ravenscraig is a former steelworks site in Scotland and is one of the largest brownfield sites in the UK. Locally sourced BSI PAS 100 compost and chipped bark were mixed in varying amounts with indigenous material to produce seven topsoil mixtures for small scale trials. The best performing mix has since been manufactured on a greater scale and applied to develop a 2 ha woodland.

Site investigation and sampling guidance

Guidance on site investigation and sampling can be found in Section 2. Water availability, weed control, light and temperature are key determinants that should be assessed to maximise plant establishment and long-term effectiveness. Areas with low soil moisture availability and also very wet soils are best avoided, since these conditions do not promote successful growth.

Monitoring and aftercare

Adequate aftercare to a project must be provided to ensure good long-term performance7. Minimal maintenance should be required for well-planned and constructed sites. However, it is recommended that an aftercare programme is put in place which may include the application of weed control substances until the plants become established, or the application of additional compost at regular intervals to boost the soil’s fertility. The programme of aftercare will depend on the individual site. On some sites, nutrients in the compost may need to be supplemented with organic fertiliser, to further enhance growing potential. Ongoing monitoring and aftercare will allow for problems to be identified and remediated early.


5. Energy crops on brownfield land The EU has set a target of 20% energy from renewable sources by 2020, which will require an increased production of biomass resources for heat, power and transport. Two main perennial energy crop species have been planted on a significant scale within the UK; short rotation coppice (SRC), mainly high-yielding varieties of willow (and occasionally poplar), and miscanthus, which is a woody perennial rhizomatous grass30. SRC is densely planted and harvested on average every 3 years. Other less common SRC crops, such as ash, alder, hazel, silver birch, sycamore, sweet chestnut, or lime can be harvested on a longer rotation31. SRC plantation can be viable for 30 years before re-planting becomes necessary. Once miscanthus is established, it can be grown to 3.5m and can be harvested annually for at least 15 years32. Other energy crop types include reed canary grass, straw, forest materials and tree management residues. Energy crops for use as transport fuels include cereals (wheat), oilseeds, sugar beet and fodder beet. Brownfield site development is growing within the UK as a method of providing sustainable solutions for material supply and to address the shortage of previously unused or ‘virgin’ land. The term ‘brownfield’ is used to refer to both known contaminated sites and any land or premises which has previously been used or developed and is not currently fully in use. Guidance provided in this document is relevant to remediated brownfield sites only. However, reference to bioremediation techniques and processes that include the use of BSI PAS 100 compost is provided in Section 10. BSI PAS 100 green compost and food derived compost can be applied during the preparation of land for energy crop production, either within soil manufacturing or applied as a soil improver. Miscanthus will grow on a wide range of soil types; however higher yields are achieved on moisture retentive soils which warm up quickly in spring, capitalising on the longest possible growing season33. Fertiliser demands for the crop are low, with the addition of fertilisers and herbicides usually only required in the first year after establishment. SRC willow crops require close contact with the surrounding soil and adequate moisture to promote good root development. Failure to obtain adequate moisture at this early establishment stage is the most common reason for plant mortality.

Establishment of Short Rotation Coppice (SRC) willow on restored soils

The trial at St Ninians, Fife was established to assess the effect of applying BSI PAS 100 green compost on a soil recently reinstated after disturbance by opencast mining. The trial was successful in determining that BSI PAS 100 green compost can be used for establishing short rotation coppice (SRC) willow.

Figure 9: Establishment of SRC willow on compost treated soil Compost enhances the water retention capability of soils and thereby improves plant establishment. Table 8 compares SRC willow establishment between soils treated with different amounts of BSI PAS 100 compost on a former landfill site.

Table 8: Willow establishment, 16 weeks after planting on a capped landfill site treated with compost

Compost (t/ha) 0 50 100 150

Number of willows established

4 14 20 16

Percentage establishment

2.5 8.8 12.5 10

NB willow establishment on treatments differed significantly

www.wrap.org.uk/gpgenergy

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/energy_crop_production/


Site investigation and sampling

The key determinants in energy crop yield are water availability, weed control, light and temperature. Energy crops such as SRC willow will produce good growth where there is sufficient moisture in the soil or soil forming material in which they have taken root. Soil pH should ideally fall between 5.5 and 7.0 for SRC willow and between 5.0 and 7.0 for giant grasses and other energy crops. These characteristics should be confirmed during the site investigation phase and addressed if necessary. The addition of compost can lead to increased mobilisation of some metals, such as zinc and lead leachate as a result of increased pH. However, even at high compost application rates, the metal concentrations should remain well within acceptable levels. Various factors including soil temperature and moisture level govern the amount of nitrogen in a compost which is likely to be available to crops in the year of application, but the most important factor is the Carbon: Nitrogen (C:N) ratio. The higher the C: N ratio, the less N will be available to crops in the year of application. Recent research and advisory information suggests that if the C:N ratio is 10:1, then 25% of the total amount of the N present in a compost will become available to growing crops within three years30. Therefore, optimising the amount of N in the compost applied in relation to C should be an important consideration during site investigation and mix design activities.

Benefits

The benefits summarised in the Introduction are particularly important for brownfield land that has previously been used for heavy industry or open cast mining which can take up to ten years to recover from the physical, chemical and environmental damage. The use of BSI PAS 100 compost can help through the provision of additional organic matter and decreased soil bulk density. Increasing the pH and conductivity can lead to increased levels of available plant nutrients, which along with improvement of a soil’s water holding capacity and root zone aeration can help to enhance vegetation establishment. Cost savings

The application of BSI PAS 100 quality compost for soil improvement or soil manufacturing is cost-effective when compared to traditional materials used for topsoil manufacture and site remediation. The use of compost with existing site materials (coal washings) and recycled aggregate at the Kinglassie former coal washing site in Fife led to cost savings of between £2.49 and £3.30 per tonne when compared to the import of 100% multipurpose topsoil, as shown in Table 9.

Table 9: The cost per tonne (£) of different topsoil options for remediation at the Kinglassie site

Mix

Cost per tonne (£)

Material Transport Mixing Total

100% multipurpose topsoil (BS 3882: 2007) 6.00 1.50 0.00 7.50

20% compost, 80% RA 2.20 1.50 0.50 4.20

Mix 1 (20% Compost, 48% coal washings material, 32% recycled aggregate)

2.26 0.75 1.20 4.51

Mix 2 (30% Compost, 42% coal washings material, 28% recycled aggregate)

2.79 0.75 1.50 5.04



Manufactured soils must be applied with sufficient depth to allow crop roots to develop normally. Roots must be able to extract adequate water and nutrients, and achieve enough anchorage to resist wind throw. For SRC willow production, compost should be incorporated to the rooting depth of the cuttings, that is 20cm deep, since this may help conserve soil moisture during dry spells30. This could be best achieved by ploughing, which inverts the soil and places the compost at the rooting depth. Minimum thickness of topsoil should be confirmed and adjusted depending on the mean summer rainfall and the known particle size and stoniness of the soil forming materials used. When applied as mulch, low rates of compost have shown to either have no effect on energy crop establishment or weed incidence or in some cases caused an increase in weeds. Higher rates of compost mulch can, however, help prevent weed growth and aid crop establishment, particularly in the first 6 – 10 weeks after application. Application rates for compost

Experience has shown that ratios of 20% and 30% by weight of compost have been mixed with existing site materials successfully to produce topsoil which fulfils the requirements for soil forming materials. These mixes have sufficiently low stone content, a suitable pH and contain appropriate quantities of plant nutrients and organic matter to promote energy crop establishment and growth30. Further WRAP trials carried out to investigate the potential use of BSI PAS 100 quality compost on brownfield sites to produce soil suitable for energy crop production have found that optimum crop yields were achieved after applications of 500 or 750t/ha34. Application levels above this had no further positive effect on crop growth. Aftercare

Adequate aftercare must be provided to ensure good long-term performance7; however, well planned and constructed sites should require minimal maintenance. It is recommended that an aftercare programme is put in place. The programme of aftercare will depend on the individual site and vegetation, and may include the application of weed control until the plants become established or the application of additional compost at regular intervals to boost the soil’s fertility. In the case of SRC, the addition of further organic or inorganic fertiliser may be required to boost soil nutrient levels and suppress weed growth during crop establishment in particular. Annual fertiliser demand for miscanthus grass is typically very low and research has demonstrated that yield is not typically improved by nitrogen addition32.

Trials to test the establishment of short rotation coppice willow on brownfield sites using food derived BSI PAS 100 compost

Silt canal sludge deposits at the 40 hectare Frodsham Dredging Grounds have been treated with food derived compost for soil improvement to support the development of SRC willow as a biomass crop. The trial will evaluate the potential for biomass yield when BSI PAS 100 food derived compost is used to improve native substrate materials.

Figure 10: Established willow Monitoring

Ongoing monitoring and aftercare will allow for problems to be identified and remediated early. These activities should be proportional to the cost and scope of the project and should include a: survey of the level of vegetation cover

across the site and plant health; survey of the overall environmental

condition of the site, for example evidence of soil erosion or deterioration, or condition of local watercourses; and

record of any signs of poor crop health.


Case studies


Bickershaw Colliery


Deep-mined coal spoil at the former Bickershaw Colliery has been treated with compost for soil improvement to support healthy growth of SRC willow as a biomass crop. The trial’s specific aim is to determine the feasibility and efficacy of food derived compost for ameliorating coal mine spoil to create soils suitable to establish SRC willow crop for biomass.

Colinsburgh, East Fife

The use of food derived compost to establish biofuel crops of brownfield land

A field trial conducted on the former whinstone quarry near Colinsburgh in East Fife to determine the feasibility of growing energy crops on brownfield land.

Dalquhandy

Establishment of commercial forestry on the former open cast coal site

Coarse grade BSI PAS100 compost can be used to further restore poor quality land, however a recognised problem is achieving an intimate mix of compost with the existing site materials. This trial investigates novel cultivation techniques to incorporate compost into the existing soil in order to establish a commercial forest.

Kinglassie, Fife

The potential for biofuel crop production on a former coal washing site

This feasibility study and trial investigated remediating a derelict 5 hectare coal washing site in West Fife using manufactured topsoil consisting of a mix of coal washings material, recycled aggregate and quality compost with the aim of running energy crop trials for a proposed new power station.

Lumley, Teesside

Energy crops on a former landfill site

This case study determines the effect of different application rates of BSI PAS 100 compost on the establishment of SRC willow crops and on weed suppression when the crop is grown on agricultural land and on a landfill site.

Northumberland

The use of food derived compost as fertiliser in willow biomass crop production on reclaimed land

A trial site was established on reclaimed opencast land at Cockle Park Experimental Farm in Northumberland which operated as a mine between 1978 and 1990. BSI PAS 100 food derived compost has been applied at two application rates and is being compared with other treatments to assess SRC willow growth on the reclaimed land.

Skinningrove, Teesside

Impacts of BSI PAS 100 compost to establish reed canary grass as a biomass crop

A field trial at the Corus Skinningrove site has been set up to examine the impacts of using quality compost blankets to restore steelworks land for biomass, control fugitive dust and improve biodiversity.

Teesside

Biomass crop production on five brownfield sites on Teesside

The project used five one-hectare sites in Teesside – former landfill and sewage sites, a shipyard, a capped slagheap and a former coke works – to investigate the effectiveness of the use of BSI PAS 100 compost to facilitate the production of energy crops on brownfield land.

Westfield, Fife

The use of food derived compost as a top dressing for Short Rotation Coppice willow

This trial examines the use of food derived compost as a top dressing applied at varying rates to short rotation coppice willow planted on a partially restored open cast mine in Fife.

Frodsham Dredging Grounds, Manchester


Silt canal sludge deposits at the 40 hectare Frodsham Dredging Grounds has been treated with food derived compost for soil improvement to support the development of SRC willow as a biomass crop. The trial will evaluate the potential for biomass yield when BSI PAS 100 food derived compost is used to improve native substrate materials.

St Ninians, Fife

Establishment of Short Rotation Coppice (SRC) willow on restored soils

The trial at St Ninians, Fife was established to assess the effect of applying BSI PAS 100 green compost on a soil recently reinstated after disturbance by opencast mining. The trial determined that BSI PAS 100 green compost can be used for establishing short rotation coppice (SRC) willow.


6. Sustainable urban drainage systems (SUDS) and green roofs The introduction of impermeable surfaces and artificial piped-drainage systems, associated with site development, disrupt natural drainage patterns increasing surface water run-off and downstream flood risk37. The use of BSI PAS 100 compost as a component of a Sustainable urban drainage system like a green roof could result in decreased rates and volumes of runoff, while accelerating the establishment of vegetation (and providing a new market for recycled materials)35. There are two distinct types of green roof: extensive - These have a relatively shallow lightweight substrate

which supports low growing, hardy drought tolerant plants; and intensive - These have a relatively deep substrate (>20cm) and

can support a wide range of plant types from grasses to trees and shrubs and as such are heavier

Further information is available from the Green Roof Centre36. Benefits and risks

There is a growing realisation that green roofs can help deliver national, regional and local biodiversity action plan targets in both the urban and the rural context37. Green roofs offer a range of environmental benefits, including: reducing rainfall run-off and creating a lag time effect aiding

storm-water management; insulating buildings38; prolonging the longevity of the roof surface membrane35 and

building (protecting from UV and temperature fluctuations)38; increasing sound insulation 35; and potentially reducing the 'urban heat island' effect and improving

air quality38. The high nutrient content of compost may be a limiting factor for the establishment of sedums in extensive roofs, since sedum species do not require a high nutrient input. It is therefore necessary to apply the right amount of compost to ensure plant growth is not excessive39. Other considerations include: The range of suitable plants able to thrive in growing media

containing significant proportions of green compost. The capacity for green roof substrates containing relatively large

proportions of green compost to support healthy plant growth in the medium to long term due to decomposition causing substrate shrinkage and general loss of organic matter38.

Sustainable urban drainage systems (SUDS)

Sustainable urban drainage systems (SUDS) serve to reduce peak rates and total volumes of storm water run-off, through the introduction of permeable paving and ‘greening’ impermeable areas such as roofs. Green roofs

Green roofs are vegetated layers that sit on top of the conventional waterproofed roof surfaces of a building. The substrates used to support vegetation in a green roof commonly comprise aggregates and various sources of organic material. BSI PAS 100 compost could potentially represent a readily available and sustainable source of this organic matter39. Extensive roofs typically have thin substrates of depths up to 100mm. Semi-extensive roofs may have depths of around 100-200mm, and depths above this are classified as intensive roofs. The shallower the substrate becomes, the more important it is for the substrate mix to be correct. Green roofs with low substrate depths can require more exact substrate compositions to ensure vegetation growth.39

Figure 11: Sedum mat for extensive green roof

www.wrap.org.uk/gpgsuds

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/suds_and_green_roofs/


Substrates for green roofs

Substrates are typically engineered to be lightweight and are primarily made of inorganic components such as crushed brick or expanded clay; this provides volume and rooting structure with little additional weight. Substrates also contain an organic component to help provide the nutrients and water holding capacity necessary for plant growth. This component may be composted pine bark, recycled vegetation, topsoil, green and food derived compost. These components are chosen to complement each other while serving different purposes; the organic content is required for vegetation growth and assists with water retention and the mineral or non-organic component provides the porosity and structural integrity of the green roof39. Inclusion rates of BSI PAS 100 green compost in green roof substrates are being investigated further.

Figure 12: Green roof on Sharrow school, Sheffield (courtesy of the Green Roof Centre)

Investigation and sampling

A site investigation to assess the suitability of retrofitting an intensive green roof will include a structural survey to confirm that the structure can support the additional weight of the proposed vegetation. It is also important to assess the materials as they must be lightweight, well drained, good at holding nutrients and water, and must not significantly leach nutrients or decompose over time8. Application of compost

The most comprehensive standards for green roof growing media can currently be found in the German roof greening guidelines40 Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau41 (FLL). These guidelines restrict the amount of organic content that can be used and therefore higher levels of organic content are rare. The limitation on organic content in the FLL guidelines is to promote sufficient substrate water permeability, long-term stability and oxygen diffusion, together with minimising the risk of fire. The recommended organic content levels from FLL are given in Table 10. These guidelines state that a higher level of organic content may be required where special forms of vegetation are used39. However, the FLL guidelines do not reflect the use of BSI PAS 100 compost. A code of practice on green roofs is currently under development in the UK.

Table 10: Organic content as specified in FLL guidelines

Type of roof Organic content

Intensive (with apparent density ≤0.8) ≤12% by mass

Intensive (with apparent density >0.8) ≤6% by mass

Extensive multiple course construction (with apparent density ≤0.8) ≤8% by mass

Extensive multiple course construction (with apparent density >0.8) ≤6% by ma s

Extensive single course construction ≤4% by mass

A recent WRAP study has concluded that BSI PAS 100 compost provides a suitable and sustainable source for the organic fraction for the vegetation support course in extensive green roof installations in the UK when combined with appropriate mineral fractions such as crushed brick35.


Case studies


Shropshire

BSI PAS100 compost as a component of the substrate in extensive green roofs

This research carried out in partnership with Vital Earth and Harper Adams University College provides an assessment of the potential for using BSI PAS100 compost as a component of the substrate used in green roof construction. It examines the performance of four different substrates in terms of plant establishment and water retention.

University of Coventry

Assessment of the use of green and food derived compost for a Prefabricated Vegetative Component (PVC)

The PVC (prefabricated vegetative component) is a pillow made of either biodegradable material or a more permanent geotextile filled with compost. It either has grass seed broadcast on the upper surface, or is used with germinated seedlings already growing in place. The aims of this project are to establish if a PVC pillow can effectively utilise green and food composted material in vegetated SUDS. Initial results show that compost has the potential to replace topsoil in constructing SUDS, and therefore will reduce the costs and material going to landfill.

STRI, West Yorkshire

Demonstration trial using compost filled grids in a car park

This demonstration trial is part of a larger project to assess the potential for a retrofitted drainage system using a compost/plastic grid system. This system has the ability to retain surface rainfall and reduce runoff from hard standings such as car parks. Vegetation is being established in this compost, in order to accentuate the water absorption. Part of the trial is to monitor grass establishment and growth in the grid/compost systems.

Green Roof Royal Horticultural Society (RHS) study

Investigation of the inclusion of compost in an intensive green roof substrate

Using a range of green roof substrates with varying proportions of green compost and inert material, the RHS are carrying out work at a field research facility at Deer’s Farm to address concerns within the green roof industry and allow practitioners to obtain research data on the effects of quality compost application within green roof substrates with respect to shrinkage, runoff composition and influence on plant communities.

London

Investigating the use of green compost in green roofs

This project investigates and demonstrates the successful use of BSI PAS 100 compost as the organic component of substrates used in green roof construction. The trial assessed the performance of substrates in terms of plant establishment and water retention.


7. Slope stabilisation and erosion control

Erosion control on the A421

This project investigates the use of compost blankets and compost socks in preventing and controlling erosion in an engineered embankment along the A421 in Bedfordshire. Compost blankets and compost socks have been applied to the 2:1 slope and compared to other erosion control applications. Results to date show that the compost socks alone reduce runoff by 90%. Thus significantly reducing erosion and sediment loss.

Figure 13: Compost blankets in A421 trial, Cranfield University Site investigation and sampling

A site investigation checklist is given in Section 2; however when assessing erosion, monitoring over a period of time to assess change may be required. This may include: aerial photography can provide a useful

tool for assessing change over a number of years; and

fixed point photography at key easily re-locatable points across a site can record important features and changes if repeated every year at the same time of year, from the same fixed points.

Soil is essential for a number of functions and services which are central to the sustainability of agro-ecosystems and the global economy. Consequently soil management and specifically soil erosion, including erosion from construction activities, is moving up the political and legislative agenda42. Wind, rain and foot traffic can erode soil, particularly when it contains low levels of organic matter. This reduces the ability of plants to establish, grow and remain healthy. The reduction in plant growth and subsequent plant residue causes less soil cover, perpetuating the erosion process. Ultimately, this process can lead to infertile land void of topsoil. In addition, this poor quality soil is not able to retain much water and is therefore susceptible to drought43. Vegetating roadside and waterway embankments provides habitat, increases biodiversity and adds amenity value to what are perceived as low quality areas. Compost can be applied generally or deployed in areas of particular concern in combination with an engineering solution for erosion control and to encourage plant growth. Combining engineering solutions and vegetation is termed ‘eco-engineering’ and can be used to stabilise shoreline and highway banks45 and slopes and to control path and waterway erosion. The use of eco-engineering is increasing as its practical applications for stabilising engineered slopes can be environmentally preferable and cost effective compared to traditional ‘hard-engineering’ solutions, such as the use of soil nails or impermeable concrete facings. Moreover, engineered slopes may also provide a market for coarse grade compost44. Application of compost

Compost can be applied directly or incorporated with a range of products to generate the following eco-engineering solutions: compost blankets; compost socks; compost in plastic grid (geocell systems); and vegetated gabions. Benefits and risks

Compost can increase grass seed germination and re-growth45, enabling the swift development of vegetation in order to improve stability46. This makes it ideal for use in slope stabilisation programmes, where soil erosion and an inability to support vegetation is a common problem that can lead to slippages – a key concern for highways contractors47. Compost offers an economically attractive option to combine with a range of proprietary products to create an eco-engineering solution.

www.wrap.org.uk/gpgerosion

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/slope_stabilisation/


Compost blankets

A compost blanket is a layer of loosely applied compost that acts like a blanket covering the surface on which it is applied, and can be used on a slope or flat land. The mixture of fine and coarse particles mat together creating a blanket that has shown to hold on 2:1 slopes, as well as more severe slopes, without slipping. However, on severe slopes lock down netting can be applied over the compost to secure it. A blower can be utilised to spread compost across the soil surface. Compost can also be raked and flattened with an excavator to place the compost on the bank45. Compost blankets are most appropriate for use in sheet flow water management situations to reduce rill formation45 rather than controlling concentrated flows with high velocity flood water. However, compost berms or slope interruption socks can be used in conjunction with this technology to further reduce the flow velocities of the water45. Compost blankets can also improve the moisture holding capacity and encourage vegetation establishment. Field trials using 50mm compost blankets have been shown to hold 12.5 to 25mm of water. A recent trial demonstrated that surface application of compost was better than incorporation to 10cm depth44 using rates of 35 and 300t ha-1. Further research is underway. Compost socks

Compost socks can be used as vegetated soft armouring systems, designed to stabilise banks and prevent erosion from flood waters and precipitation runoff45, and ongoing storm-water management. Compost socks can be specified in a range of sizes and contain a range of growing media, depending on the particular end use. They can be filled on site or remotely and transported to site for installation. The weight and anchoring systems can withstand storm run-off velocities and hydraulic shear stresses. Soft defences can be cost effective, multi-purpose in nature and can often benefit existing wildlife, by providing areas of habitat. Compost socks have advantages over traditional soft armouring devices (brush mattresses, coconut fibre logs, turf re-enforcement mats) as the compost facilitates the establishment of both seeded and live stake plantings45. During the restoration of Cultrig Burn corridor at the Polkemmet-Heartlands site, Whitburn, compost-filled socks served as a basis for reed development and to guide the water through the channel. A standard method for filling the socking48 was developed using a purpose-built mini-excavator with a converted bucket fitted with an auger and exit pipe. Alternatively socks can be filled using a compost blower. During placement a cradle can be constructed to aid lifting in a controlled manner. A site-specific methodology should be derived for the transport of compost-filled socks. Once positioned, compost socks can be secured in place with pegs.

Application of compost to reduce erosion on an engineered slope, Nafferton Farm, Northumberland

The project examines the effectiveness of compost to stabilise the surface and subsurface of an engineered slope in order to both prevent erosion and enhance vegetation establishment.

Figure 14: Compost blankets in slope stabilisation trial, Nafferton Farm Centenary Riverside

An innovative approach was used to stabilise this clay bank and protect it from erosion. Compost was used for bank stabilisation and soil creation. The compost soil was sown with a fast growing seed mix to provide vegetation cover to protect the compost from erosion. Compost socks have been installed along the riverbank to protect it from scouring. The compost has significantly reduced erosion and has provided the growing medium in which plants are thriving.

Figure 15: Compost socks, Centenary Riverside


‘Greening’ reinforcement

BSI PAS 100 compost was used as a base for the creation of new pathways at Marsden Golf Club. Compost provides vital support to roots and grass – thereby creating an attractive ‘green’ pathway – and also reduces the costs associated with gravel and concrete pathways49. Grass development on each of the seeded plots has been remarkable, with the food-derived compost providing the fastest growth for healthy vegetation in the first year. The plots where compost had been applied also experienced reduced surface erosion and run-off in the autumn and winter. The results suggest that compost-based geogrid pathways provide an excellent alternative to expensive gravel or concrete pathways.

Figure 16: Green pathways produced from BSI PAS 100 compost at a Lancashire golf course

Geosystems and compost

There is a variety of geosystems designed for an array of engineering solutions including soil and slope reinforcement, drainage and erosion control. Geocell, geogrid and geoweb are part of the range of geosystems designed to incorporate soil and vegetation as a ‘greening’ engineering solution. More information on geosystems can be found on the AggRegain website50. Vegetated gabions

Gabions are an established engineering solution used to protect shorelines and river banks against erosion and stabilise slopes at the toe while at the same time allowing free movement of water to the underlying soil. Gabions are rectangular containers of galvanized wire, which are filled with stone. The integration of the compost with the stone in a gabion can enhance growing conditions providing a suitable moisture retentive and nutrient rich substrate for vegetation. During a recent demonstration project on the use of BSI PAS 100 green compost for vegetating gabion structures it was concluded that inclusion of compost through the full volume of gabion structure is particularly effective in retaining growth of vegetation. Therefore for the establishment of vegetation on gabion structures using green compost the following scheme is recommended: Compost requirement 240 litres per cubic metre of gabion. During stone laying apply approximately 20 litres of compost

after every one to two layers of stone. After the final layer of stone is in place, apply 40 litres of

compost and brush in to surface. Sow appropriate seed to surface. (It may be preferable to mix

seed with compost prior to application.)51

Case studies


Cranfield University

Study on best management practices (BMP) against compost blankets and socks

This work investigated the suitability of Compost Erosion Control Blankets (CECBs) for runoff and erosion control, on construction sites under two simulated rainfall events (5 and 75 year return period storm events (RPSE)) as compared with currently adopted Best Management Practices.

Centenary Riverside, Rotherham

Erosion control and habitat creation on the award winning nature reserve

As part of the creation of the nature reserve, compost blankets have been applied to an engineered slope to reduce erosion. Along the riverbanks compost socks have been installed to protect it from scouring. The compost has significantly reduced erosion in both areas and has provided the growing medium in which plants are thriving.

Cultrig Burn, Polkemmet

Compost socks used in bank stabilisation

Compost socks were laid along the Cultrig Burn Bank for erosion control. A comparative assessment with other methods took place.

http://www.aggregain.org.uk/geosystems



Redding Park, Falkirk

Trial of the effects of the depth and quality of mulch/compost for control of soil erosion and slope stability

A series of trials have taken place at Redding Park housing development, near Falkirk to investigate the benefits of using compost to control erosion. Compost blankets and compost socks have been installed on a slope and are being trialled against other materials, such as wood mulch.

Nafferton Farm, Northumberland

Application of compost to reduce erosion on an engineered slope

The project examines the effectiveness of PAS100 compost to stabilise the surface and subsurface of an engineered slope in order to both prevent erosion and enhance vegetation establishment. The trial is being conducted on a purpose-built artificial embankment constructed by the University of Newcastle upon Tyne.

STRI Slopes , West Yorkshire

Application of compost to reduce erosion on a 2:1 slope

This project assesses soil erosion, soil slippage and vegetation establishment on STRI slopes. Two different treatments have taken place where compost has been used as mulch and as a soil improver.

Liverpool John Moore University

Compost use for geotechnical stability of engineered slopes on two different soil types

Based at White Moss Horticulture, this project examines the compost use for geotechnical stability of engineered slopes on two different soil types. The results to date provide initial evidence that the addition of compost to varying soil textures can reduce soil erosion on slopes that are set at both 25° and 45°.

Lancashire, Nelson

Erosion control of footpaths on Marsden Park Golf Course

This trial assesses the utility of composts as a medium in robust, aesthetically appropriate paving surfaces on the Marsden Park golf course in Lancashire. It examines the use of both food derived and green BSI PAS 100 composts as a gravel filler substitute in pathway construction and for supporting grass growth.

East Lothian

Compost socks safeguard water quality

In 2009 guidelines introduced by the Scottish Environment Protection Agency (SEPA) required the set up of a water decontamination process to control potential leachate run-off from the composting process. To alleviate the issues presented by the run-off, compost socks were installed as a filtering process using compost-filled socks. In the reed beds compost-filled socks served as a basis for reed development and to guide the contaminated water through the system.

Warrington

New Cut canal restoration Project Warrington Borough Council

The trial aims to demonstrate how compost-filled gabions can enhance biodiversity during the creation of an Urban Ecology Park. Results will be compared to traditional gabion designs that incorporate rock fill and coir matting.

SCRI, Dundee

Compost use for geotechnical stability of engineered slopes, erosion control, and restoration of riparian habitats in Scotland

This study investigates the effects of using BSI PAS100 compost on the stability of an engineered slope and looks at the establishment of vegetation. The use of compost improved the slope performance and provided substantial erosion control, decreased run-off and promoted plant growth.


8. Recreation and sports turf

BSI PAS 100 compost on football turf

When used in football turf applications, BSI PAS 100 compost has been shown to improve the wear tolerance of the turf and also improve surface hardness, whilst remaining within the desired surface hardness range. Compost also provides a simple means of greening up football pitch turf quickly and evenly. It also helps to keep the surface aerated, increases turf drought resistance and promotes an even surface52. BSI PAS 100 compost on golf courses

Application of compost material as a top dressing on golf fairways has also shown to produce a greater depth of colour than those treated with a peat-containing material. Furthermore, tee areas on a golf course need to be level and free draining as this gives a good playing surface even in wet conditions. Using a sand and compost mix helps to ensure this52.

Figure 17: Castle Stuart golf course trial

BSI PAS 100 compost is typically used to promote root zone and turf establishment and as a top dressing agent on football pitches and golf courses. In the creation and maintenance of sports turf, green compost and food derived compost can be used to construct a golf course or sports pitch through the manufacture of soil and as a topdressing or fertiliser during maintenance. BSI PAS 100 compost can help to enhance vegetation establishment, suppress weed growth and promote plant growth through the provision of nutrients and improvement of a soil’s water holding capacity. When used on golf courses, BSI PAS 100 compost has been shown to produce a better quality of play due to healthier grass growth and better drainage, helping the course to better cope with the adverse effects of severe weather. Benefits

There is much evidence to demonstrate that compost is a suitable material for soil manufacture, surface dressing and fertilisation, to aid turf establishment. Compost can be combined with the existing indigenous soils to improve soil structure, reduce compaction in the surface layer, improve water holding capacity and improve soil drainage and aeration. Compost can also be applied as a layer on top of existing surface materials to promote grass and plant growth and reduce the risk of erosion. BSI PAS 100 compost application provides specific benefits to sports turf; these include53: the promotion of faster turf development but without

excessive growth as unlike sand-based dressings, compost can retain nutrients and make them available to the turf for a longer period;

improved turf density and colour due to slow release nitrogen, iron and magnesium within the compost;

enhanced appearance of turf without necessarily encouraging a large amount of top growth – thus reducing the cutting frequency when compared to areas treated with fertiliser;

increased water holding capacity - leading to cost and labour savings related to irrigation;

turf protection from nitrogen-sensitive diseases such as dollar-spot; and

reduced nutrient leaching as unlike traditional sand-based turf dressings, compost can retain nutrients and make them available to the turf for a longer period. Grass remains green without excessive growth, or increased mowing frequency.

www.wrap.org.uk/gpgsportsturf

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/recreation_and_sports_turf/


Financial benefits

The use of BSI PAS 100 compost for sports turf development and maintenance has been shown to have financial benefits when compared to the use and import of traditional materials used for topsoil manufacture. For example, the construction of the future championship golf course on the former coal mining site at the Polkemmet-Heartlands development, Scotland, has benefited from substantial cost savings. The cost of importing topsoil for site establishment would have been in the region of £15 per tonne, with additional costs of £2 per tonne for spreading and seeding. The cost of producing a topsoil using a mixture of colliery shale and BSI PAS 100 compost, including spreading and seeding, was calculated as £7.22, representing a saving of just under £10.00 per tonne54. This cost saving is presented in Table 11.

Table 11: Cost comparison of creating topsoil with importing topsoil from off site (1000 tonnes equivalent)

Component/process

Compost and colliery shale

Topsoil

£/t Total £ £/t Total £

Compost – purchase, delivery and grading (250 tonnes)

10.00 2,500

Topsoil – purchase and delivery 15.00 15,000

Colliery waste – crushing (750 tonnes)

2.29 1,718

Blending with compost 1.00 1,000

Spreading 1.00 1,000 1.00 1,000

Seeding 1.00 1,000 1.00 1,000

Total to produce 1000 tonnes of soil

£7,218 £17,000

Cost per tonne £7.22 £17.00

Figure 18: Polkemmet golf course

Cost savings from the use of compost as top dressing material

When used as a top dressing and/or for soil fertilisation, compost not only enhances water retention and turf growth, but can also save money on turf treatments making it a serious alternative to conventional materials, particularly if the temporary aesthetic issues following spreading are avoided by incorporating the compost into a sand-based mix and aerating the turf prior to application. When compared to the use of traditional top dressing materials (such as fen soil) for turf maintenance and repair at Carnoustie Golf Club, BSI PAS 100 compost led to cost savings of approximately 30% or around £13 per tonne55. Material costs are about the same for compost and traditional top dressing materials but cost savings are realised through the reduced transport costs for compost. Similarly, Monifieth Golf Links in East Central Scotland, the purchase of BSI PAS 100 compost to mix with sand as top dressing was £10/m3, compared to £51/m3 for the purchase of fen soil dressing. Over the site, this led to annual cost savings of £1,56056. Site investigation and sampling

Site investigation should be designed on a case by case basis; a checklist of key considerations is given in Section 2. For the application of compost as a topdressing or fertiliser, the key issues to consider are water and nutrient availability, weed control, light and temperature. Other determinants that should be assessed to maximise plant establishment and long-term effectiveness during site investigation include: site topography; risk of site flooding; risk of drought on the site; and heavily trafficked areas, prone to

erosion


Considerations

There are a number of potential risks that should be considered during the application of compost for sports turf establishment and maintenance. For close-mown turf, such as golf courses and football pitches, compost is unlikely to be adequate as a sole source of nitrogen fertiliser. However, it is effective as a long-term and slow release nutrient source. Particularly high rates of compost application can reduce traction and playability of turf on football grounds and golf courses. This can be a particular problem during wet conditions when the surface can become excessively soft due to the moisture retention properties of compost. In areas prone to flooding and water inundation, it is recommended that lower compost application rates are applied52. There has also been some evidence of a muddying effect on turf surfaces when compost is applied alone without being mixed with site materials, making the ground unsuitable and unacceptable for players52. This can be remedied by screening the compost to a finer grade, mixing it with sand and aerating the soil before spreading57. However, on golf course application, there can be evidence of compost on the turf surface a few days after application even with the use of a 0-5mm grade material. Therefore, in some circumstances it may be necessary to use a BSI PAS 100 compost product <3 mm in particle size52.


The amount of compost that is appropriate for a site will depend on the properties of the compost to be applied, the quality of the existing site material, and the required condition of the site after application. Application rates will also be site specific and factors such as, the topography of a site, the soil infiltration rate, the weather conditions prior to application and future weather patterns, the proximity to surface water courses and groundwater level will influence these. Compost application during very dry conditions should be avoided as compost will not adequately blend with existing materials and may be at risk from wind and traffic erosion during especially dry periods. It is recommended that compost top dressing is applied during the spring or autumn to avoid run off and material loss during periods of heavy rain and to avoid periods of hot and dry weather and drought which would restrict the level of incorporation of the compost into the underlying turf and soil52. In summary, the optimum time to spread compost is when the weather is warm and the soil moist. Where soils are particularly low in nutrients compost may be supplemented with a nitrogen fertiliser. Nitrogen in compost is mainly in a slow-release form and may not provide enough nitrogen in the first few weeks of growth58. Compost application also reduces the risk of turf erosion. Turfed areas can suffer from wear and tear and surface erosion, particularly in heavily trafficked areas. Damage is often most evident during dry summer and drought conditions. The application of an organic material such as compost to such areas aids soil moisture retention and assists the grass to recover from wear and tear. This is particularly beneficial on fescue-dominated turf52. Examples of WRAP trials where there has been effective application of BSI PAS 100 compost for sports turf establishment and improvement are shown in Table 12. For more information on WRAP trials go to www.wrap.org.uk/farming_growing_and_landscaping/.

http://www.wrap.org.uk/farming_growing_and_landscaping/


Table 12: WRAP trials on the use of BSI PAS 100 compost in sports turf application.

Application type WRAP trial example

STRI, West Yorkshire Football turf establishment and maintenance

An application of no more than 6 litres/m2 was reported as the most effective, and a recommendation of no more than two applications per annum. Application levels higher than this may lead to reduced surface playability. It is also recommended that compost particle size is <10mm52.

Carnoustie Golf Club Golf course fairway maintenance

Sand and 6mm grade BSI PAS 100 compost were mixed at a ratio of 3:1 (sand: compost). This mix was then added to grass seed and a seaweed meal. The seaweed meal provided an additional source of micro nutrients which encourage root growth55.

STRI, West Yorkshire Golf course root zone manufacture

The main aim of this trial was to compare the rate of turf establishment on a sand based rootzone in which a BSI PAS 100 green compost and food-derived compost had been used as organic amendments. This was carried out for both football-type (perennial ryegrass) and golf green-type turf (fescue-bent mixture). In this case the optimum inclusion rate would have been between 10 and 20% by volume58. However, the actual optimum will be dependent on the individual compost material used.

Castle Stuart Golf Course, Inverness and STRI, West Yorkshire Golf course top dressing

Research is being conducted to understand the potential for BSI PAS 100 green and food-derived composts within root zone products for use as top dressings on golf courses. Trials are ongoing with monitoring results and conclusions to be published by WRAP in 2011.

Monifieth Golf Links Golf course and closely mown turf fertilising

Compost as a fertiliser on golf courses and closely mown turf sites is most effective when applied on areas with poor growth or on locations that are prone to drought conditions. Compost can be used on a more regular basis on tees and walk-off areas in order to encourage wear recovery without encouraging weeds or disease. The preferred compost particle size is <10mm57.

K-Club Northern Ireland These trials investigated the use of BSI PAS 100 food derived compost products in golf course maintenance across Ireland.

Case studies


Morecombe

Compost mix helps restore football club's ground

A root zone product containing lignite, sand and green compost was used to aid turf establishment at Morecambe Football Club which had been experiencing problems with an uneven surface and patchy grass.

Marsden Park Golf Course, Lancashire

Path stability

This trial assesses the utility of composts as a medium in robust, aesthetically appropriate paving surfaces on the Marsden Park golf course in Lancashire. It examines the use of both green and food derived BSI PAS 100 composts as a gravel filler substitute in pathway construction and for supporting grass growth.

Polkemmet-Heartlands project

From coal mine to golf course

The Polkemmet-Heartlands Project near Whitburn, West Lothian is a major land regeneration scheme that is transforming 120 ha of derelict land that was previously used for open cast mining, into two championship golf courses, hotel and leisure facilities and 2,000 new homes. Manufactured topsoil made from BSI PAS 100 compost and crushed colliery spoil has been developed and tested to assess its suitability for application within golf course establishment and mixed used developments.


9. Landscape maintenance


Compost mulch was added as a 50mm layer to an area of at least 250mm beyond the edge of the planting pit at a rate of 0.03m³ per tree during a 12-month municipal tree planting trial in North Somerset. Compost was also added as a soil amendment at a rate of 1:5 of excavated soil or 0.15m³ per tree. The rates were based on commonly used application rates and the trees were irrigated on a weekly basis61. Compost offers benefits when compared to the application of ordinary tree bark, as it is rich in nitrogen3, and is also less likely to be blown or washed away.

Figure 19: Compost as mulch in flower beds

For landscape applications, BSI PAS 100 quality green and food derived compost are usually applied as mulch or for soil improvement. Quality compost can enhance plant establishment and growth and help to suppress weed growth through the effective provision of nutrients and improvement of a soil’s water holding capacity. There is a lot of evidence that demonstrates the suitability of organic materials such as BSI PAS 100 compost for soil improvement applications. BSI PAS 100 compost is used in many public and private gardens and tourist attractions. Benefits

Compost application can improve water retention. This is particularly important for young transplanted plants and trees as water loss and shortage can have an adverse effect on their appearance and can delay their establishment. Compost has been shown to act as a soil conditioner which, when applied, produces flower beds with few weeds and plants with a much higher establishment success rate than experienced when compost is not applied59. When used as a soil improver, nutrients within compost enrich the soil and aid root establishment. Plants grow quicker, bigger, and flower for longer with the compost’s nutrients feeding them60. Compost also reduces the need for maintenance, improves a soil’s weather resistance, and produces aesthetically pleasing landscapes. When applied as mulch on a tree planting scheme for North Somerset Council, compost kept weed cover at about 30%, and represented a 50% reduction in weed cover when compared to untreated plots61. On the same trial, compost applied as mulch led to increased tree lateral shoot extension. On sections of the site treated with compost, new shoots measured 9.97cm compared to 6.09cm for untreated areas three months after application. After nine months, the shoots in the mulched area were 10.75cm compared to 7.99cm in the untreated plot61.

www.wrap.org.uk/gpgmaintenance

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/landscape_maintenance/


Quality green compost can be produced from kerbside collected garden waste and applied in public areas. This has been shown through a compost application trial carried out by North Lanarkshire Council where derelict land was transformed into an award-winning open space that boasts hundreds of healthy trees62. Organic matter within compost improved the soil’s crumb structure and tilth, making it more workable, and enhancing water infiltration and drainage rates, which can be a particular problem with clay soils that are prone to water logging. When applied in layers at the base of trees to reduce soil erosion problems, compost also encourages worms to come to the surface which helps reduce soil compaction and increase aeration63. Financial benefits

Quality compost offers a financially competitive and effective alternative to the importing of topsoil and the use of herbicides and other inorganic fertilisers as the material can be used to encourage the improvement of existing low quality soils or be combined on site with soil-forming materials to make topsoil. The cost of compost application as a mulch or fertiliser is unlikely to be less than that of herbicide or peat application over the long term due to associated management requirements (including irrigation and pest and disease control). However, the cost of compost is typically less than that of herbicide. For example, a saving of £5.98/m3 was realised from the use of BSI PAS 100 compost when compared to peat application on a large-scale ornamental tree growing trial at Barcham (Table 13). This represents a 24% saving64.

Table 13: Cost comparison of compost on the Barcham Trees project (2007)

Component

Total mix cost (£/m3)

% d

iffe

renc

e in

cos

t

Total saving

Peat, bark and crushed brick

Green compost and bark £ / m3 Percent

Substrate 17.33 13.12 75.72 4.21 24.28

Nutrients 7.61 5.84 76.74 1.77 23.26

Total mix 24.94 18.96 76.03 5.98 23.97

A 33% by volume (v/v) quality green compost was mixed with 67% v/v composted bark and applied at a rate of 4kg/m3 during a large-scale ornamental tree growing trial at Barcham Trees. The mix matched the nursery’s standard growing medium (comprising peat, bark and crushed brick) in terms of commercial performance and handling properties64. As compost can be locally sourced and produced, it provides a cost-effective and environmentally attractive alternative to plastic mulches or herbicides.

Compost helps gardens bloom at Cotswold Wildlife Park

Cotswold Wildlife Park's soil has significant clay content. In order to make this soil more workable and a more effective growing medium, compost produced from garden trimmings such as grass cuttings, prunings and leaves was used regularly as a soil improver to add organic matter to the soil.

Figure 20: Compost being applied by hand at Cotswold wildlife park Compost helps Gardenscape to flower in Cove Bay

To improve the soil condition at a 400 house development in Cove Bay, 300m2 of compost has been used on the site’s 8,000 square-metres of shrub and flower beds. A 5mm application was used during an extensive planting scheme, once the plants were established an additional 10mm mulch was laid on top60. Site investigation and sampling

Water and nutrient availability, light and temperature are key determinants that should be assessed to maximise plant establishment and long-term effectiveness. Areas with low soil moisture availability and very wet soils are best avoided, since plants rooted into excessively dry or waterlogged soils are unlikely to root and grow successfully.


Case studies Case study Description

North Somerset


A 12-month trial was carried out on a municipal tree planting scheme in North Somerset. Quality compost was applied as a mulch, as a soil amendment and as a combination of the two.

Isle of Wight

Island paradise blooms brighter with compost

Quality compost made from recycled garden material was used as a soil conditioner for commercial-scale landscaping projects in the Isle of Wight. Disposing of green waste for composting cost half that of importing topsoil, peat and new compost.

Cotswold Wildlife Park

Compost helps gardens bloom

Cotswold Wildlife Park's soil has significant clay content. In order to make this soil more workable and a more effective growing medium, compost produced from garden trimmings such as grass cuttings, prunings and leaves has been used regularly as a soil improver to add organic matter to the soil.

Abbey House Gardens

Use of compost to create enchanting display

The five acre Abbey House Gardens site in Malmesbury was treated with BSI PAS 100 compost produced from garden waste to form formal flower beds which are home to more than 2,000 different varieties of plant.

North London

Compost helps to preserve arboretum for future generations

BSI PAS 100 compost made from kerbside collected kitchen and garden waste was used to protect a range of rare and unusual trees in a North London arboretum. Compost was applied as mulch to the roots of the trees to prevent soil compaction and provide nourishment and as a soil conditioner for flower beds and shrubs on the site.

Northampton

Jack Moody Ltd uses compost to create haven for commuters

BSI PAS 100 compost was used to landscape a massive new housing estate in the M1 commuter belt in Northampton. 2,000m2 of compost was used within the planting schemes and seeding throughout the site, which led to very successful growth, particularly in the hedgerows.

Ely, Cambridgeshire

Container production of trees in growing medium based on green compost – Barcham Trees

In a large-scale ornamental tree growing trial, using a representative range of twelve popular ornamental tree subjects, a peat-free growing medium based on BSI PAS 100 green compost and bark was shown to provide an effective growing medium in terms of commercial performance and handling properties.

Monitoring and aftercare

Adequate aftercare to a project must be provided to ensure good long-term performance7. Minimal maintenance should be required for well-planned and constructed sites. However, it is recommended that an aftercare programme is put in place which may include the application of weed control substances until the plants become established, or the application of additional compost at regular intervals to boost the soil’s fertility. The programme of aftercare will depend on the individual site. On some sites, nutrients in the compost may need to be supplemented with inorganic fertiliser, to further enhance growing potential. Ongoing monitoring and aftercare will allow early identification and remediation of problems.


There are different size grades of compost available on the market, each of which is suitable for different landscape applications. For example, finer grades of compost can be applied as a soil improver or a top dressing. Coarser, woodier compost types are most effectively applied to provide stable, effective and long-lasting mulch. Compost can be handled with similar ease to peat mixes. One consideration when handling compost is increased bulk density, which can raise concerns regarding the movement of freshly potted stock64. The amount of compost that is appropriate for a site will depend on the properties of the compost to be applied, the quality of the soil forming material available on site, or imported, and the intended land end use. However, WRAP trials have shown compost to be effective when applied as either mulch, as a soil improver or in soil manufacture in landscape applications.


10. Bioremediation Past industrial use has led to many brownfield sites across the UK being contaminated with hydrocarbons and toxic metals65 66. Legislation, along with sustainable and financial drivers to reduce material sent for landfill disposal make remediating site materials an environmental and economically preferable option. What is bioremediation?

Bioremediation is a process which uses micro-organisms or enzymes to remove contaminants making the soil suitable for vegetation establishment. Quality composts are suitable materials for use within bioremediation projects as they are able to support large varieties of micro-organisms and have the potential for degrading many contaminants65. Ex situ bioremediation of contaminated soils and water using organic materials such as compost is well established. Excavated soil is typically arranged into a biopile or windrow, and aerated with a passive or active system. Inorganic nutrients or microbial cultures can be added to improve the process. Alternatively, contaminated soil can be mixed with composts in situ to reduce contaminant levels and improve soil structure and fertility65. Benefits and Considerations

There are numerous benefits to the application of BSI PAS 100 compost, as detailed in the Introduction of this Guide. Additionally, BSI PAS 100 compost application provides specific benefits to bioremediation projects. Organic materials such as BSI PAS 100 composts have the potential to remediate contaminated waters through processes including68: adsorption; reduction by biomaterials; and reduction by micro-organisms (either already present in the

material or colonising from the surrounding environment). When organic material is added to contaminated soils or water, porosity, pH and oxygen diffusion capacity increase65. As BSI PAS 100 compost is generally rich in nutrients such as phosphorus, nitrogen and carbohydrates, it promotes the growth of organic pollutant degraders and, as it provides a slow-release of these nutrients, leaching is lower than in the case of inorganic nutrient (fertiliser) application.

Removal of contaminants from in situ smouldering off gases, Bishopbriggs, Scotland

An analysis of the effectiveness of green and food derived composts at reducing the levels of contamination within emissions produced during the self sustaining remediation of contaminated soil has been conducted. Results show that composts demonstrate effective remediation of the emissions with removal rates reaching up to 70% over the duration of the remediation process. New Cut canal restoration Project, Warrington

A section of contaminated silted up canal is being restored to create an Urban Ecology Park. Compost socks and compost-filled gabions are being used to enhance biodiversity and their effectiveness will be compared to traditional gabion designs that incorporate rock fill and coir matting. Contamination pathways within both the content of the compost-filled gabions and through the compost amended substrates covering contaminated canal dredgings will be assessed.

Figure 21: New Cut canal restoration Project, Warrington

www.wrap.org.uk/gpgbioremediation

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/good_practice_guide/bioremediation/


Remediating Ebbw Vale

A trial at Ebbw Vale assessed the treatment of soil contaminated with polyaromatic hydrocarbon (PAH) and total petroleum hydrocarbon (TPH) using ex situ bioremediation. BSI PAS 100 green compost and contaminated soil were mixed at a ratio of 3:1 (contaminated soil to compost) and placed in a biopile67. The biopile was covered with a geo-synthetic membrane and the remediation process was monitored for 11 weeks67. The trial also demonstrated the cost effectiveness of BSI PAS 100 compost. Two separate biopiles were trialled, one amended with horse manure and the other with <20mm BSI PAS 100 green compost (both at 10% v/v). The cost per tonne of BSI PAS 100 compost was £7.06 and the cost for the horse manure was £6.10 per tonne65. However, sourcing and arranging loading/delivery of horse manure took considerably more time and effort resulting in a greater cost per tonne than for the same amount of BSI PAS 100 material.

Figure 22: Ebbw Vale - Bioremediation

BSI PAS 100 green and food derived composts have demonstrated that they offer an effective method for remediating contaminated soil and water in low flow-through (passive) systems68. Similarly, BSI PAS 100 composts have been found to be an effective filter media during the treatment of contaminated gas streams from in situ soil smouldering69. An analysis of the effectiveness of green and food derived composts at reducing the levels of contamination within emissions produced during the self sustaining remediation of contaminated soil and water has shown that composts can remove up to 70% of the toxic substances over the duration of the remediation process69. WRAP research has shown that food derived compost can have a greater effect on the bioremediation of contaminated soils and water than green compost, due the higher nutritional levels (specifically nitrogen). High levels of nitrogen are beneficial to bioremediation systems dependant on microbial reduction mechanisms. Further work is currently being conducted by WRAP to determine how closely compost based systems can compete with chemical reducing agents. Financial benefits

The application of BSI PAS 100 compost within bioremediation projects has demonstrated financial benefits when compared to ex situ chemical treatments and other methods of soil remediation. The remediation of groundwater contaminated by hexavalent chromium using BSI PAS 100 accredited composts, derived from green and food derived sources, utilised treatment columns consisting of 2.5kg BSI PAS 100 compost and 2.5kg gravel. These were able to treat 1.45m3 of contaminated groundwater for less than a tenth of the cost of the ex situ chemical treatment system used68. Site investigation and sampling guidance

Once compost has been established as suitable for part of the bioremediation process, a more detailed site investigation should be undertaken. Samples should be analysed to determine the concentration of toxic substances using published standard analytical methods in an accredited laboratory. A checklist for site investigation and sampling can be found in the Tools Section. Metal mine water remediation, Newcastle

This laboratory trial examines the use of BSI PAS 100 compost to remediate metal (zinc, lead, cadmium and copper) contaminated mine water. Findings so far show promising results in terms of the potential for BSI PAS 100 compost to attenuate metals and will feed into field trials once completed.



The rate of application of BSI PAS 100 compost is influenced by the type and concentration of contaminants and the pH7. The end use of the site also influences the appropriate rate of compost application. Particularly high application rates must be justified with evidence as to why these rates are required. If high application rates are required, care must be taken to minimise the risk of pollution7. The majority of projects where BSI PAS 100 compost has been applied within the bioremediation process are currently still in the trial stage and so advice on mixing ratios is limited. Maximum permissible concentrations of toxic substances in soil following the application of compost at different levels of acidity should be referred to7. However, it is acknowledged that in some cases the application of compost may increase the mobility of some contaminants, thereby creating a pathway. In these cases, those responsible for the project should check there is not a receptor in the vicinity that is susceptible to the available contamination and justify the application of compost to the relevant regulatory authority. Adequate aftercare to a project must be provided to ensure good long-term performance7. The programme of aftercare will depend on the individual site. On some sites, nutrients in compost may need to be supplemented with inorganic fertiliser to further enhance growing potential. On other sites, the addition of chemical substances may be required to further reduce toxic substance concentration. Ongoing monitoring and aftercare will allow for problems to be identified and remediated early.

Use of BSI PAS 100 compost in contaminated groundwater

Contamination of groundwater by hexavalent chromium Cr(VI) is of concern due to it being toxic, carcinogenic and mutagenic in nature, as well as highly mobile in soil and aquatic systems. This study assesses the potential of BSI PAS 100 accredited composts, derived from green and green/food waste sources, for the remediation of Cr(VI) contaminated groundwater. A series of batch and column experiments were conducted, followed by a pilot trial on a contaminated site.


Use of BSI PAS 100 compost in contaminated groundwater

Contamination of groundwater by hexavalent chromium Cr(VI) is of concern due to it being toxic, carcinogenic and mutagenic in nature, as well as highly mobile in soil and aquatic systems. This study assesses the potential of BSI PAS 100 accredited composts, derived from green and green/food waste sources, for the remediation of Cr(VI) contaminated groundwater. A series of batch and column experiments were conducted, followed by a pilot trial at a chromium groundwater remediation plant in Falkirk.

New Cut canal restoration Project, Warrington

A section of contaminated silted up canal is being restored to create an Urban Ecology Park. Compost socks and compost-filled gabions are being used to enhance biodiversity and their effectiveness will be compared to traditional gabion designs that incorporate rock fill and coir matting. Contamination pathways within both the content of the compost-filled gabions and through the compost amended substrates covering contaminated canal dredgings will be assessed.

Metal mine water remediation, Newcastle

This laboratory trial examines the use of BSI PAS 100 compost to remediate mine water from metal contamination from zinc, lead, cadmium and copper. Findings so far show promising results in terms of the potential for the BSI PAS 100 compost to attenuate metals and will feed into field trials once completed

Remediating Ebbw Vale

A trial at Ebbw Vale assessed the treatment of soil contaminated with polyaromatic hydrocarbon (PAH) and total petroleum hydrocarbon (TPH) using ex situ bioremediation. BSI PAS 100 green compost and contaminated soil were mixed at a ratio of 3:1 (contaminated soil to compost) and placed in a biopile. The biopile was covered with a geo-synthetic membrane and the remediation process was monitored for 11 weeks.


Appendix – Mixing Ratios The mixing ratios reported herein are compiled from a range of site trials commissioned to assess different aspects and uses of compost and are therefore case specific. For further information regarding the effectiveness and potential suitability of these mix ratios please refer to the related project report.

Case study Compost application

Land end use Mixing ratio

Soil manufacture and habitat creation

Lambton, County Durham

Establishment of woodland in former coke works using BSI PAS 100 compost and paper mill crumb

Soil manufacture Woodland and grassland development

1:1:5 - GC: paper mill crumb: colliery shale (for subsoil)

Cross Lane

Former landfill restored into a new community woodland

Soil manufacture Woodland and grassland development. Carbon Sequestration.

5:7:5 - silt: sand: GC. For woodland tree planting = 1m depth; for shrub species = 0.75m; for meadow grassland = 0.5m

Cronton Colliery, Knowsley

Restoring a former colliery site to a wildlife rich habitat

Soil improvement Wildflower grassland development

30mm layer of GC into the top 120mm of spoil

Ayrshire

Woodland establishment on restored land using PAS100 and recycled minerals

Soil improvement and mulching

Woodland development

8:1 - GC: rock dust mixes were backfilled to each planting in one trial and applied as mulch in another trial

Greenoakhill, Scotland

Woodland establishment of a restored landfill site

Soil manufacture Woodland and grassland development

GC incorporation with site materials at rates of 12.5%, 25% and 50% by volume.

Dunbar, SE Scotland

The effect of green compost on the establishment of rough grazing, arable grazing & amenity trees on a restored limestone quarry

Soil improvement Woodland and grassland development

GC incorporation with site materials at rates of 5% and 10% by volume

Royal Ordnance, Chorley

Former munitions factory transformed into the public open space

Soil manufacture Grassland 2:1 (GC: existing subsoil)

North Somerset


Surface treatment Tree planting GC mulch was added as a 50mm layer to an area of at least 250mm beyond the edge of the planting pit at a rate of 0.03m³ per tree. GC was also added as a soil amendment at a rate of 1/5 of excavated soil or 0.15m³ per tree.


Establishment of amenity grass on shale subsoil

Soil improvement Grassland GC applied at rates of 625t/ha and 1,250t/ha




Damside, Scotland

Soil amelioration on former open cast coal sites

Soil improvement Grassland GC applied at rates of 750t/ha and 1,500t/ha

Housing and mixed use development

Chorley

Royal Ordnance Munitions Factory, transformed into the village of Buckshaw

Soil manufacture Housing development 2:1 (GC: existing subsoil)

North Lanarkshire

Going ‘green’ with compost reaps rewards for Scottish housing developer

Soil manufacture Housing development Topsoil produced using compost and sandy loam at a ratio of 2:1 and spread at a thickness of 150mm across the site.

Ebbw Vale


Soil manufacture Mixed use development - new education, healthcare, employment and rail infrastructure

GC mixed with the colliery shale at ratios of up to 4:10 (compost to soil) to produce suitable topsoil for use on the site.

Energy crops on brownfield land

Lumley, Teesside

Energy crops on a former landfill site

Soil improvement and surface treatment

Energy crop production – SRC willow

4.5, 9 or 18 t/ha of GC

Kinglassie, Fife

Biofuel crop production on a former coal washing site

Soil manufacture Energy crop production - various

Mix 1: 20% GC, 80% coal washings/recycled aggregate [made up from 60% CW*2 + 40% RA*3] by weight Mix 2: 30% GC, 70% CW/RA [made up from 60% CW + 40% RA] by weight

Applied at depths of 30, 50 and 70cm

Teesside

Biomass crop production on five brownfield sites

Soil improvement Energy crop production - various

0, 250, 500 and 750 tonnes of GC per hectare were applied in the trial. Results show that 500 t/ha is most effective.

Westfield, Fife

The use of food derived compost as a top dressing for Short Rotation Coppice willow

Soil improvement Energy crop production - SRC willow

Applied at rates of 5t/ha, 10 t/ha, 20 t/ha - FC*4

Applied at rates of 19 t/ha, 38t/ha, 76 t/ha - GC

Northumberland

The use of food derived compost as fertiliser in willow biomass crop production on reclaimed land


GC - applied at the maximum permitted rate equivalent to 500 kg total nitrogen per hectare. Additionally a half rate (250 kg/ha) FC treatment was included, as well as a control with no fertiliser added.

Bickershaw Colliery



35 tonnes of FC compost per 20m x 30m plot (equivalent to 500 tonnes per ha) and 70 tonnes per plot (equivalent to 1000 tonnes per ha)




Frodsham Dredging Grounds, Manchester



Mixtures of FC and GC applied at a rate of 76 tonnes per plot (equivalent to 1000t per ha.) and at a rate of 38 tonnes per plot (equivalent to 500t per ha.).

St Ninians, Fife

Establishment of SRC willow on restored soils at the Open Cast Coal Mine


3 rates of GC addition; nil, 300 t/ha and 600 t/ha

Skinningrove, Teesside

Using quality compost blankets to restore steelworks land for biomass, control fugitive dust and improve biodiversity

Soil improvement Energy crop production – reed canary grass

GC at rates of 250 t/ha, 500 t/ha and 750 t/ha


Establishment of amenity grass on shale subsoil

Soil improvement Grassland GC applied at rates of 625 t/ha and 1250 t/ha

Sustainable urban drainage systems (SUDS)

London

BSI PAS100 compost as a component of the substrate in extensive green roofs

Green roofs Green roof substrate Mixtures of crushed brick to compost at 90:10 and crushed brick to compost at 80:20

Slope stabilisation and erosion control

Centenary Riverside

Compost helped to create an awarding winning wetland nature reserve in Rotherham

Erosion control and bank stabilisation - Compost blanket and socks

Wetlands Mixture of BSI PAS 100 compost, subsoil free of bricks and leaf mould in a ratio of 8:9:1 (compost: subsoil: leaf mould) applied on central banks.

Nafferton Farm, Northumberland

Application of compost to reduce erosion on an engineered slope different soil types


Embankment construction

Two replicated plots received a surface treatment of BSI PAS 100 GC of 5 or 10cm depth; two more plots received a 5 or 10cm depth treatment of BSI PAS 100 GC incorporated into the soil; fifth treatment included the use of geotextile.

SCRI, Dundee

Compost use for geotechnical stability of engineered slopes, erosion control, and restoration of riparian habitats


Embankment construction

BSI PAS 100 GC is incorporated at two rates of 35 and 300t/ha

Recreation and sports turf

Carnoustie Golf Club

Golf course fairway maintenance

Surface treatment Golf course 6mm grade GC mixed at a ratio of 3 to 1 (sand:compost) to form divot mix. Grass seed was then added alongside a seaweed meal.

STRI, West Yorkshire

Comparison of BSI PAS 100 green and food derived composts for turf – root zone manufacture

Soil manufacture Football and golf courses

80:20 (sand: compost) mixing rate. Three rates of nitrogen fertiliser were applied: 3.2 g/m2, 6.4 g/m2 and 9.6 g/m2




Polkemmet-Heartlands project

From coal mine to golf course

Soil manufacture Golf course GC sieved to 10-20 mm and crushed colliery waste successfully applied at rates of 75:25 and 70:30 (colliery spoil:compost).

Landscape maintenance

Cove Bay

Compost helps Gardenscape to flower in Cove Bay

Soil improvement and mulching

Housing development - public and private parks and gardens

5cm of GC mixed into the soil during development. When the plants are established, a 10cm mulch is then laid on top.

Ely, Cambridgeshire Barcham Trees

Soil manufacture Ornamental tree development

33% by volume GC (<10mm grade) and 67% by volume composted bark.

Bioremediation

Ebbw Vale

Bioremediation of hydrocarbons in soils

Bioremediation of hydrocarbons

Housing and mixed use development

Soil contaminated with TPH was treated using ex situ bioremediation in biopiles. <20 mm GC*1 applied at 10% by volume.

Ebbw Vale


Soil manufacture and bioremediation

Mixed use development - new education, healthcare, employment and rail infrastructure

GC mixed at a ratio of 3:1 (contaminated soil to compost) In bioremediation biopiles

*1 GC: Green compost

*2 CW: Coal washings

*3 RA: Recycled aggregates

*4 FC: Food-derived compost


Glossary Aggregation: refers to the way in which sand, silt and clay particles come together to form a soil structure Ameliorant: substance added to soil to improve growing conditions for plants Attrition: as part of soil remediation technology, removes fine particles and contaminants from the surface of primary material (soil) Biomass: refers to the mass of biological organisms in an area or ecosystem at any given time Bioremediation: is a process which uses micro-organisms or enzymes to breakdown or remove contaminants Biowaste: source-segregated biodegradable waste Brownfield: refers to both known contaminated sites and any land or premises which have previously been used or developed and not currently fully in use (this excludes agricultural land) Bulk density: the mass of a unit volume of soil, generally expressed in g/cm3. Light and porous soils have low bulk densities, whereas heavy and compacted soils have high bulk densities Carbon sequestration: long-term storage of carbon dioxide or other forms of carbon to mitigate global warming Cation exchange capacity (CEC): the total amount of exchangeable cations that a particular soil, or soil forming material can adsorb at a given pH. Light textured soils (in the sandy categories) possess low cation exchange capacities (CEC) and adding compost raises the CEC of these soils. This enables the soil to better hold onto nutrients, such as potash and nitrogen, which would otherwise leach beyond the rooting depth. Compost: solid particulate material that is the result of composting, that has been sanitised and stabilised and that confers beneficial effects when added to soil, used as a component of a growing medium, or is used in another way in conjunction with plants. This definition refers to BSI PAS 100 compost for the purposes of this document Composting: process of controlled biological decomposition of biodegradable materials under managed conditions that are predominantly aerobic and that allow the development of thermophilic temperatures as a result of biologically produced heat Domestic use: compost use by members of the public in their own gardens, communal or shared gardens, and allotments Electrical conductivity: measurement relating to the concentration of soluble ionic constituents, particularly ammonium, calcium, chloride, magnesium, nitrate, phosphate, potassium, sodium and sulfate Food derived compost: Compost that has been made from suitable low-risk food wastes such as household and commercial kitchen wastes. Facilities producing such composts are authorised by Animal Health to ensure that they achieve appropriate conditions to ensure their safety Fertiliser: soil amendment containing nutrients (macronutrients and micronutrients), added to promote plant growth Green compost: The feedstock used to produce green compost is source segregated material collected independently from other waste streams from sources such as domestic gardens, municipal parks and recreational areas Green waste: Arboreal and other botanical residues such as grass clippings and other plant residues derived from parks, gardens, nurseries and amenity areas and sometimes waste from vegetable or fruit processing activities Growing medium: material, other than soils in situ, in which plants are grown Land reclamation: the recovery of land from a brownfield or underutilised state to make it suitable for reuse achieved through stabilisation, contouring, maintenance, conditioning, reconstruction and vegetation establishment.


Land remediation: the process of making a site fit-for-purpose through the removal or containment of contaminants. Environmental damage is reversed or treated through the management, removal, sealing or treatment of dangerous substances or stabilisation in order to render the site safe for a specific use, but not necessarily for all possible uses. Land restoration: the process of making a site fit-for-purpose through (among activities carried out), amelioration of the site’s soil or soil forming materials1 Micro-organisms: include bacteria, algae, fungi and protozoa. They recycle nutrients and actively decompose organic matter Mulch: substance spread and allowed to remain on the soil surface to conserve soil moisture, suppress weeds and shield soil particles from the erosive forces of raindrops, run-off and wind Oxygen diffusion capacity: the capacity of the soil to transfer oxygen to plant roots PAS: Publicly Available Specification Rotavator: a machine designed to break up soil using rotating blades Sewage sludge cake: dewatered, organic-rich sewage sludge that is an output from the sewage treatment process Soil improver: material added to soil in situ primarily to maintain or improve its physical properties, and which may improve its chemical and/or biological properties or activity Stable, stabilised: degree of processing and biodegradation at which the rate of biological activity under conditions favourable for aerobic biodegradation has slowed and microbial respiration will not significantly resurge under altered conditions, such as manipulation of moisture and oxygen levels, or temperature or the addition of a source of water soluble nitrogen Subsoil/substrata: the layer of soil below the layer of topsoil Sustainable Urban Drainage Systems (SUDS): Surface water drainage systems developed in line with the ideals of sustainable development are collectively referred to as Sustainable Urban Drainage Systems (SUDS) Topsoil manufacture: Blending of soils available on site and potentially other organic or inorganic materials with BSI PAS100 compost to produce a soil that suits the requirements of the site and which provides the same function as topsoil Tilth: State of aggregation of soil and its condition for supporting plant growth Topsoil: the uppermost layer of soil, where the majority of biological soil activity, concerning micro-organisms and organic matter, occurs Water holding capacity: the ability of soil to retain water and thus making it available for a longer period of time in dry conditions. Wetlands: an area where the soil is saturated with moisture either permanently or seasonally


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44 WRAP (2009), Compost use for geotechnical stability of engineered slopes, erosion control, and restoration of riparian habitats in Scotland. 45 WRAP (2010), Ecological survey: Centenary Riverside Central Bank. Centenary Riverside, River Don. 46 WRAP (2010), Compost socks safeguard water quality in East Lothian. 47 WRAP (2010), Slope stabilisation. Application of compost using a compost blower. 48 WRAP (2009), Use of Filtrexx compost socks for bank stabilisation and erosion control in the restored Cultrig Burn corridor at the Polkemmet-Heartlands site, Whitburn, Scotland. 49 WRAP (2010), Compost, gravel and geo-stabilised amenity paving on Marsden Golf Course. 50 AggRegain.wrap.org.uk/geosystems/index 51 WRAP (2009), Demonstration project on the use of PAS 100 green compost for vegetating gabion structures. 52 WRAP (2006), Demonstration trials of the utilisation of composted materials in the maintenance of sports and amenity turfgrass. 53 WRAP (2010), Sports turf applications. 54 WRAP (2009), Polkemmet-Heartlands Topsoil Recycling Scheme. 55 WRAP (2009), Quality compost use at Carnoustie Golf Club. 56 WRAP (2008), Monifieth golf links – Landscape and regeneration case study. 57 WRAP (2008), Compost is top performer in unique UK golf course trial. 58 WRAP (2009), Comparison of PAS100 green and food derived composts for turf – rootzone manufacture. 59 WRAP (2006), Island paradise blooms brighter with compost – Case study. 60 WRAP (2004), Compost helps Gardenscape to flower in Cove Bay – Case study. 61 WRAP (2008), North Somerset Council - Compost mulch proves its worth in council tree planting scheme – Case study. 62 WRAP (2007), Compost helps new trees flourish on North Lanarkshire housing estate – Case study. 63 WRAP (2008), Compost helps to preserve arboretum for future generations – Case study. 64 WRAP (2007), Container production of trees in growing medium based on green compost – Barcham Trees. 65 WRAP (2009), Use of PAS 100 compost as an amendment for the bioremediation of hydrocarbons – Trailblazer case study. 66 CL:AIRE, Contaminated Land In Real Environments. 67 WRAP (2009), Ebbw Vale Steelworks Reclamation – Soil use and management for the creation of urban green space with particular emphasis on the contribution of green compost to the landscape scheme and WRAP involvement. 68 WRAP (2010), PAS100 compost for remediation of chromium contaminated groundwater. 69 WRAP (2010), Effectiveness of Green and Food derived Compost at Removing Contaminants from In situ Smouldering Off Gases.

http://www.wrap.org.uk/downloads/Case_study_-_drylaw.8297b4e6.9590.pdf

http://www.wrap.org.uk/construction/how_do_i_reduce_waste/landscaping/slope_stabilisation.html

http://aggregain.wrap.org.uk/geosystems/index.html

http://www.wrap.org.uk/downloads/WRAP_Compost_Sports_Amenity_Turf_R_130106.4a4daa0b.2408.pdf

http://www.wrap.org.uk/farming_growing_and_landscaping/landscape_and_design/why_use_compost_and_digestate/sports_turf.html?utm_source=short-url&utm_medium=brochures&utm_campaign=sports-turf

http://www.wrap.org.uk/downloads/ORG33-020_-_Ecosse_report_-_Final.4ede3a26.3480.pdf

http://www.wrap.org.uk/downloads/case_study_-_carnoustie.d9b25877.8013.pdf

http://www.wrap.org.uk/downloads/Case_study_-_Monifieth.4768d3fd.5828.pdf

http://www.wrap.org.uk/downloads/Case_study_-_Monifieth.a3721abc.5828.pdf

http://www.wrap.org.uk/downloads/Wyevale.2cb89050.3011.pdf

http://www.wrap.org.uk/downloads/GardenscapeCaseStudy.0e1328ec.438.pdf

http://www.wrap.org.uk/downloads/Case_Study_North_Somerset_Council.27d98973.6228.pdf

http://www.wrap.org.uk/downloads/Organics_case_study_-_North_lanarkshire.e1daaaf6.7501.pdf

http://www.wrap.org.uk/downloads/Case_study_-_London_Waste.b636a898.5840.pdf

http://www.wrap.org.uk/downloads/ORG33-015_-_barcham_final_report_-_approved.dbeeee69.4556.pdf

http://www.wrap.org.uk/downloads/Approved_-_ERS_2008_report.ba2cff80.6773.pdf

Waste & Resources Action Programme

The Old Academy 21 Horse Fair Banbury, Oxon OX16 0AH

Tel: 01295 819 900 Fax: 01295 819 911 E-mail: [email protected]

Helpline freephone 0808 100 2040

www.wrap.org.uk/organics

This document was developed by:

With the assistance of:

The green roof centre Recycle-To-Land Research Limited Envar

Front cover photography: Land restoration Ebbw Vale

WRAP and URS/Scott Wilson believe the content of this report to be correct as at the date of writing. However, factors such as prices, levels of recycled content and regulatory requirements are subject to change and users of the report should check with their suppliers to confirm the current situation. In addition, care should be taken in using any of the cost information provided as it is based upon numerous project-specific assumptions (such as scale, location, tender context, etc.). The report does not claim to be exhaustive, nor does it claim to cover all relevant products and specifications available on the market. While steps have been taken to ensure accuracy, WRAP cannot accept responsibility or be held liable to any person for any loss or damage arising out of or in connection with this information being inaccurate, incomplete or misleading. It is the responsibility of the potential user of a material or product to consult with the supplier or manufacturer and ascertain whether a particular product will satisfy their specific requirements. The listing or featuring of a particular product or company does not constitute an endorsement by WRAP and WRAP cannot guarantee the performance of individual products or materials. This material is copyrighted. It may be reproduced free of charge subject to the material being accurate and not used in a misleading context. The source of the material must be identified and the copyright status acknowledged. This material must not be used to endorse or used to suggest WRAP’s endorsement of a commercial product or service. For more detail, please refer to WRAP’s Terms & Conditions on its web site: www.wrap.org.uk