Recycling with AD,

Feedstock, Operator and Digestate Issues

By Dr Les Gornall

Recycling with AD

Biogas

Digestate

Fertiliser to

Agriculture

Feedstock

Food

Wastes

Energy

Crops

Farm

Manure

Operations/

Regulations

• CHP

• Gas to Grid

• Industrial

Boiler

• Drying Plant

• Vehicle fuel

CNG

£FIT

£RHI

Food, Fuel & Fibre crops

Recycling with AD

Reference: Waste Management World - Local Generation AD Plant, 2011

Feedstock Availability

CostStoragePreparation

Operating RegulationsTrainingRetention

Digestate Management

Feedstock - Available and Valuable

• 90-100 million tonnes of agricultural by-products like manure and slurry

• 16-18 million tonnes of food waste (from households and industry)

• 1.7 million tonnes of sewage sludge dry matter.

• Each £10/T in added value or saved cost = £1,000,000,000 per

year to the country – enough money to buy 2,000 primary

schools a year.

www.biogas-info.co.uk/faqs.html

Feedstock - Available and Valuable

Feedstock availability because:

Feedstock defines Regulations applied

Feedstock controls Acidosis/Alkosis

Feedstock controls Reaction Rate

Feedstock produces Biogas

Feedstock produces Compost Fibre

Feedstock produces Liquid Fertiliser

Feedstock determines Trucking costs

Feedstock determines Pre-treatment

Feedstock determines Digester selection

Feedstock determines Gate fees

Feedstock determines Landfill costs

Feedstock Availability = Access to Finance

• Feedstock Contract Duration = Term of the

Bank Loan

• A one year feedstock contract = a one year

bank loan and pro rata

• The availability of feedstock controls

access to finance for AD Plant Capital

Expenditure

“Are you getting enough feedstock?”

Surveyed some plants PROjEN had been involved in[May 2015]:

• “There’s no more available” (SS food waste, England)

• “Food waste includes wellington boots, lots of wellington

boots” (there is a quality issue as well as an availability issue- LKG)

• “Every council that collects food is only receiving 50% of the

food waste generated” (England, Food waste plant)

• (Recycling?) “the people that do, do and the people that

don’t, don’t” ( More education is required – LKG)

• “Use of special starch bags is a barrier… that has the

potential to be removed.”

• “There is not enough food waste to run at full output”

(England, manure and food waste plant)

“Are you getting enough feedstock?”Replies May 2015:

• “We cannot get enough feedstock locally – we are now

importing some from Scotland where there is a surplus

since the ban on landfilling food waste came into being”.

• “The plant (in Scotland) is being expanded to cope with the

large amount of surplus food waste since the landfill ban.”

• “The problem is access to food waste”

It would help AD Plants in England if there was a similar ban on

sending organic matter to landfill as there is in Scotland and

(Beginning in) Northern Ireland

(see NNfCC anaerobic digestion deployment in the UK – 2nd annual report)

Feedstock COST - Waste

• Feedstock used to come with big gate fees offset against

the landfill tax (currently Landfill Tax = £82.60/T)

• Split the difference with the source of the waste and the

AD plant developer had an income from gate fees of £20-

40/T

• On a 30kTPA plant = £1.2 Million per year

• Now, food wastes producing good gas are in short supply

and gate fees are falling towards zero

• New commercial operations have started to convert waste

into digester feedstock for purchase by AD plants for £30/T

• That is a shift of -£60/T on front end value

Feedstock COST – Energy Crops

• The issue FOOD VS FUEL

• All of the AD plants in development in the UK will only require

1% of UK arable crop land while Generating 1TWh electricity,

enough to supply around a quarter of a million UK homes;

• Feedstock cost is highly regional – Maize does not grow well in

the West and an agronomist is required to evaluate success in

crops on a field by field basis.

• See ‘Biogas from Crop Digestion’ Task 37 IEA Bioenergy’

Feedstock COST – Energy Crops

AD Can help the agricultural sector• Poor prices for agricultural produce

• £20 a tonne for potatoes just sold (below production

cost)

• Large scale dairies offering 19p a litre for milk (below

cost of production) - Grassland is becoming idle or

under-used

• Loss of the dairy industry in the UK accelerating under

global competition

• Bad years for farmers = good years for AD feedstock?

• The AD industry cannot plan on a prediction of bad years

ahead for farmers

There are good examples of AD-farm co-operation

Feedstock COST – Energy Crops

The relationship between agriculture and AD

Barkip – photo credit Luddon Construction Ltd.

Feedstock COST?

“ [The local Scottish farmer] had virtually stopped traditional mixed

farming due to the cost of fertilisers making cereals production

impossible. SEPA was asking for bunding on all slurry tanks - no

money to pay for the civils work required therefore no food

production from the farm and he had opened a farm shop as a retail

operation to stay on the land.

I offered to take his slurries, store them in big stores in bunded

enclosures and give him back nitrogen enhanced fertiliser . The

predicted NPK looked very attractive, so much so that the farmer was

able to design a new farming enterprise to grow cereals on marginal

land in the west of Scotland and return to mixed farming. ”

It’s not just marginal land in the UK: In the USA….

Digestate

fertiliser

CHP

Desert land $10 per

acre reclaimed for

Growing maize

Desert $10 per acre

Growing soya -

fixes nitrogen

Husbandry 2 people /1000 head

Milk

To the

nation,

Butter

and

cheese

to the

world

Bedding fibre

No power bills

manure

Maize

Feedstock Cost includes depacking, screening,

making “soup” from difficult waste

Magherafelt IVC

UK Gate fees currently

only cover the cost of the

processing of the organic

waste into a digester

feedstock

Much organic waste is

only addressable with

composting techniques

resulting in a loss of

available organics to AD

Cost of storage

Current cost of a

silage clamp for

10,000 tonnes of

silage is about

£250,000 or £25/T

Spread over 5 years

the cost of storing a

year’s feed is £5/T

Plus machinery,

operators and diesel

for handling.

Making soup means grinding contaminants

May 2015:

• “The food waste stopped my separator/ screening machine when it

was fed a wishbone”

Car suspension wishbone

Preparing Feedstock – Ligno-Cellulose?

Long Straw (over 5cm long) forms ‘ships ropes’ inside the digester

Large proportions of untreated garden/wood waste (in wet digesters)

BUT one problem is another opportunity – research efforts are

working towards conversion of this into chemical feedstock or

digester soup – there is a lot of this material available

Preparing means excluding from feedstock:

• Tri-butyl tin (wood preservative)

• Large amounts of disinfectants

• Potentially Toxic Elements (PTE’s) e.g. copper in

pig feed

• Oil and petrol products

• Glass and Sharps

• Plastic

• Iron bars and chains

Destroy Bacteria

Contaminate Digestate

Recycling with AD

Reference: Waste Management World - Local Generation AD Plant, 2011

Feedstock AvailabilityCostStoragePreparation

Operating Regulations

TrainingRetention

Digestate Management

DSEAR 2002

Responsibility for safety is with the owner

Assess and quantify risks

Reduce risks ALARPDefine Maintenance

and inspection requirements

ATEX

Run and Maintain plant in line with

design requirements

Planning

Planning consent requirement – AD plants

Design of plant will have constraints after acquiring consent

Important to check conditions e.g. height restrictions, lightening

protection, and noise and traffic during operation.

Gelliargwellt Farm in Gelligaer near Nelson

(South Wales) , Barton Willmore, 2013Biogas holder with lightning protection rods -

Wikipedia Article (Anaerobic Digestion), 2015

Odour Control – EA and Planning requirements

Active Odour control on storage tanks and waste storage areas is

considered to be the best technique by the Environment Agency.

The requirements should be assessed and if required the tanks and

buildings should have odour control measures.

The type of odour control unit will be dependent on the odorous

compounds within the air to be treated:

• VOC’s (aldehydes, ketones, organic acids)

• Sulphur compounds (Hydrogen sulphide, R – SH)

• Nitrogen compounds (NH3, R-NH2)

Bunds and Confined Spaces

Ref. CIRIA publications on Containment and Bunds

‘Google’ Confined Space Training for details of your local training facilities.

Feedstock and Regulations

Manure + Crops + farm spread digestate and ‘digestate not a waste’

ADD food waste and regulations for waste processing apply -‘digestate is a waste’.

You can avoid the worst of the legal waste handling processes by converting waste to a product. In this case the ‘product’ (digestate) needs to Meet PAS110/ADQP

Kemira, Digestate Treatment ,2015

• Energy Crops / Farm Manure

• Source Separated kitchen food waste

• Catering waste

• Abattoir waste

• Cooking Oil

• Glycerol

Acceptable Feedstock List - : Appendix B ADQP

<0.5% plastic in digestate

(after biosolids reduction to gas)

= <0.05% plastic in feedstock?

EN 13432 bio-degradable bags are allowed

PAS110 achievable ref. Plastic Contamination

Animal by-products (ABP's) = products of animal origin that are

not intended for human consumption.

Hides and skins Fallen stock Pet animals Zoo and circus

animals Hunt trophies Manure Ova Embryos and semen

Catering waste

Used cooking oil

Former foodstuffs

Butcher and slaughterhouse waste

Blood

Feathers

Wool

ABPR – Animal by-products regulations

Training and Retention• The number of operators required for a plant is determined by the

loading rate of the digester (see appendix)

• There are about 100 biogas plants a year being built, two a week requiring a minimum of 2 trained operators per week.

• “once you train an operator someone will offer more money”

• Rural areas seem to have more family loyalty and have a higher success rate in retaining good operators

• “Best operators I have trained – one was an industrial painter, one a truck driver.”

Recycling with AD

Reference: Waste Management World - Local Generation AD Plant, 2011

Feedstock AvailabilityCostStoragePreparation

Operating RegulationsTrainingRetention

Digestate Management

Digestate IssuesDigestate storage – restriction in deployment to land such as Nitrate Vulnerable Zones and Soil Phosphorus limits.

Digestate should meet standards set out in “Quality Protocol” and “PAS 110” which ensures the digestate can be sold as a high nutrient rich fertiliser.

The storage required is for a minimum of 5 months but for security more than 6 months is often built.

These are big tanks, 6 times bigger than the digesters.

“ the whole business case for AD hinges around digestate”

(large digester operator UK)

NVZ Zones – 12th February 2013

Digestate Issues – storage, cost, land banks

6 Months Storage of digestate

Digestate storage and spreading

May represent 50% of the operating

budget

of the plant

• Quality Meat Scotland recently

accepted PAS110 for cattle ground

• Northern Ireland is still evaluating

• England has more experience and

is positive about digestate.

Summary

• 185 AD plants built plus about 350 being built in the UK mainland and 150 in NI have only claimed access to about a tenth of organic waste & <1% of the arable crops.

• Access to organic wastes is the major policy issue – Scotland is leading the way but finance may demand at least temporary security from energy crops.

• We need more than two newly trained operators a week, but there are some great examples in the UK

• The industry is learning from design and operating errors – the regulations are evolving rapidly. Most are simply the existing UK industrial regulations for health, safety, build quality and operator responsibility.

• The pressure on feedstock prices, FIT and RHI digression is putting increasing financial pressure on AD plants with the smallest units the first casualty. The industry is still embryonic and still lobbying for continued support in a noble endeavour to convert waste to electricity and remove landfill and GHG.

• There is a need to improve financial yields and this conference may provide some measure of how the value of the outputs can be improved through new and innovative processes and novel products.

Appendices – Useful Tables

• The current Feed in Tariff and RHI for Biogas plants with useful hot

water (Note: pasteurisation heat is eligible for RHI)

• Northern Ireland rules for Landfilling organic waste April 2015

• Highlights of the NNfCC second report on AD deployment in the UK

• The Operating Regime required to manage a biogas plant at different

loading rates

• Catagories of treatment required for ABPR materials

Thank You!

Dr Les Gornall BSc.(Hons),D.Phil, C.Biol. FRSB

Process Consultant

PROjEN Ltd

Part of CAPITA

DD: 01928 752 568

Mob: 07921 388 422

Email: les.gornall@capita.co.uk

Version 2.1.1

Waste Management – Edinburgh AD Plant , 2015

Appendices – Useful Tables

• The current Feed in Tariff and RHI for Biogas plants with useful hot

water (Note: pasteurisation heat is eligible for RHI)

• Northern Ireland rules for Landfilling organic waste April 2015

• Are you getting enough feedstock? Highlights of the NNfCC second

report on AD deployment in the UK

• The Operating Regime required to manage a biogas plant at different

loading rates

• Catagories of treatment required for ABPR materials

April 2015 FIT

• Note this is the value of methane put to chp units and rhi

for the hot water from the engines. For biogas value

multiply by the fraction of methane in the biogas

<250kw <500 >500 Yield

Income p/kwh S M L kWhe S M L

FIT on generation 10.13 9.36 8.68 4 0.40 0.37 0.35

Export electricity G'tee 4.77 4.77 4.77 3 0.14 0.14 0.14

RHI sale 0 0 0 2 0.00 0.00 0.00

april 2015 RHI 7.62 5.99 2.24 Total 0.55 0.52 0.49

Income £/ m3 methane

“Are you getting enough feedstock?”

Northern Ireland

The Department of Environment (DOE) implemented a ban on

Landfilling SS Food Waste from 1st April 2015

• By 1 April 2016 food businesses that produce more than

50kg of food waste per week are to present that food waste for

separate collection.

• By 1 April 2017 food businesses that produce between

5kg and 50kg of food waste per week to present that food waste

for separate collection, and food businesses to ensure that food

waste is not deposited in a lateral drain or sewer.

• Hospitals will also be required to present food waste for

separate collection from 1 April 2017.

“Are you getting enough feedstock?”

The REA reports the key points from the NNfCC Anaerobic digestion deployment in the UK second annual report :

• There are currently 185 operational AD plants in the United Kingdom, 102 of which are farm-fed and 83 of which are waste-fed;

• AD plants currently operational in the United Kingdom require almost 2 million tonnes of food waste, 636,000 tonnes of manure or slurry, 1.2 million tonnes of crops, 229,000 tonnes of crop waste and 1.2 million tonnes of other waste each year;

• The estimated cropping area required by operational AD plants in the United Kingdom is 27,800 hectares; equivalent to around 0.5% of UK arable crop land;

• There are 500 AD projects under development in the United Kingdom; 343 of which are farm-fed and 157 of which are waste-fed;

• AD plants currently under development in the United Kingdom require over 4 million tonnes of food waste, 2 million tonnes of manure or slurry, 3 million tonnes of crops, 200,000 tonnes of crop waste and over 2 million tonnes of other waste each year.

“Are you getting enough feedstock?”• The estimated cropping area required by AD plants in development in the United

Kingdom is just over 60,000 hectares; equivalent to around 1% of UK arable crop land,

much of which could feasibly be used in rotation with crops destined for food

markets. This contribution would result in the generation of just over 1TWh electricity,

enough to supply around a quarter of a million UK homes;

• Small and medium scale developments (500kWe and below) have faced severe tariff

cuts over the past 12-months, as a result of the FIT cost control mechanism;

• Biomethane injection plants have increased more than fourfold over the past year as a

result of RHI support;

• The pipeline for biomethane injection facilities remains strong, but following the recent

tariff structure change and as a result of the RHI cost-control mechanism, activity is

expected to slow.

- See more at: http://www.nnfcc.co.uk/news/anaerobic-digestion-deployment-in-the-united-

kingdom-second-annual-report-published#sthash.diXkdTnX.dpuf

Full Report from:

- Lucy Hopwood

Lead Consultant – Bioenergy & Anaerobic Digestion

Tel:+44 (0)1904 435182 l.hopwood@nnfcc.co.uk

“Are you getting enough feedstock?”

• The UK produces over 100 million tonnes of organic material

that is suitable for treatment by AD. This includes:

• 90-100 million tonnes of agricultural by-products like manure

and slurry

• 16-18 million tonnes of food waste (from households and

industry)

• 1.7 million tonnes of dry sewage sludge.

www.biogas-info.co.uk/faqs.html

Electrical output at 85% VSR

Daily Organic

Loading Rate

kg-VS/m3

Digester VOLUME (m3)

6,000 4,000

MWe MWe

3.3 1.2 0.8

4 1.5 1.0

5 1.8 1.2

6+ 2.2 1.5

KEY – OPEX AND

MANAGEMENT

Simple Lab TVFA/NH4

Daily Lab TVFA/NH4

Intensive lab checks

Foam+NH4 issues

24 hour active

management with on

site chromatography

OPERATING REGIME VS LOADING RATE

ABPR CategoriesCat 1 – Highest risk (BSE) plus ‘international catering waste (from

ships etc.), zoo and circus animals’. Not for AD – Incinerate or

Render

Cat 2 – High risk. AD feedstock allowed if pressure cooked to the

EU Standard (133°C/3 bar/20 minutes).

EXCEPTIONS: Manure, Digestive Tract Content, Milk and

Colostrum can be digested with pasteurisation but without

pressure cooking.

ABPR CategoriesCat 3 – Low risk – intended for human consumption and can be

treated via AD.

• Raw meat intended for human consumption

• Waste from food manufacturers and retailers

• Eggs, and other by products that do not show signs of

transmissible disease

• All UK derived catering waste (i.e. from domestic and

commercial kitchens)

• PASTEURISATION FOR MAX 12mm Particle size is 1 hour at

70 Deg. C