engineered solutions international rethinking the ‘waste hierarchy’ euring ian m. arbon msc,...

Engineered Solutions International

Rethinkingthe

‘Waste Hierarchy’

EurIng Ian M. Arbon MSc, MBA, CEng

FIMechE, FASME, FEI, FInstR

“Materials for a Greener Environment”01 November 2005IMechE HQ, London


EurIng Ian M. Arbon MSc, MBA, CEng, PE

FIMechE, FASME, FEI, FInstR

Rethinking the Waste Hierarchy

30+ years experience in delivering Energy from Waste Chairman – Energy, Environment & Sustainability Group – IMechE Chairman – Engineering Forum for Energy – ICE, IMechE, IEE, IChemE, CIBSE, EI Chairman – Renewable Power Committee, Power Industries Division – IMechE Distinguished Lecturer on “Renewable Energy & Sustainability” - ASME


Some Definitions


“’When I use a word’, Humpty Dumpty said in rather a scornful tone, ‘it means just what I choose it to mean – neither more nor less.’”

- Through the Looking Glass (1872)

In this presentation we shall also look at the meaning of some words: ‘waste’, ‘recycle’, ‘incineration’, etc.


Dictionary Definitions of Waste

‘Refuse from places of human or animal habitation’

‘Anything rejected as useless, worthless, or in excess of what is

required’

‘Anything unused or not used to full advantage’



Other Definitions of Waste


“Any subject or object in the categories set out in Annex 1 of the Waste Framework Directive (91/156/EEC), which the holder discards or intends or is required to discard”

- European Union

“a resource that is not safely recycled back into the environment or the marketplace.”

- ZeroWasteAmerica


Waste Arisings - UK



Historical Analysis of Household Waste in UK


Million tonnes / year 1905 1955 2005

Coal Ash 4.8 4.6 0.4

Food Waste 0.3 0.5 2.6

Glass 0.1 0.3 2.7

Paper/Card/Rags 0.1 0.7 8.5

Plastics 0.0 0.0 2.8

Metals 0.1 0.4 2.6

Garden Waste 0.0 1.0 8.5

Other 2.4 3.3 7.3

Total 7.8 10.8 35.4

Waste per capita per year

181kg 211kg 592kg

Population 43.0m 51.9m 59.8m


Definition of the ‘Waste Hierarchy’

1 – Reduce–

2 – Re-use–

3 – Recycle–

4 – Recover–

5 – Reject



Definition of the ‘Waste Hierarchy’

1 – Reduce (do not generate waste items)

–2 – Re-use (find another use for the

same item)–

3 – Recycle (turn into a different item)–

4 – Recover (usually heat and power)–

5 – Reject (usually dispose to landfill)Rethinking the Waste Hierarchy


Analysis of the ‘Waste Hierarchy’

1 – Reduce• It would seem to be axiomatic that the best way of dealing with ‘waste’ is not to generate it in the first place!• Despite the ‘hierarchy’ having been with us for many years now, waste arisings in the UK continue to grow at around 3% per annum, so it is clearly not achieving its primary objective of reducing wastage.



Analysis of the ‘Waste Hierarchy’2 – Re-use

• The second priority, i.e. re-using items rather than throwing them away, is also highly commendable.

• Differs from “recycle” in that it finds another use for the same item, rather than changing it into a different item.

• “Re-use” is far easier to achieve in less developed economies than it is in a sophisticated, consumer-orientated society. We live in a “throw away, disposable” society and it may take several generations to change our thinking in this area.




3 – Recycle• The third priority, “recycling” waste products, is not as straightforward as it might appear.• Recycling involves the transformation (usually requiring energy input) of the waste product into another, different, product, e.g. the transformation of waste plastic cups into pens and pencils.



Analysis of the ‘Waste Hierarchy’3 – Recycle (cont.)

• In some cases, the energy required in the recycling process (especially when separation, collection and transport are taken into consideration) is greater than the energy required to make the product from raw materials. This appears to be particularly true in the case of recycling paper:“It was disclosed last year that more than a third of Britain’s waste paper and plastic went to China for recycling.” – Daily Telegraph 18.07.05Rethinking the Waste Hierarchy



4 – Recover• “recover” is regarded by many environmentalists as a ‘bad thing’ and the option of disposing to landfill will shortly no longer be available to us!

• On the other hand, many waste products can be excellent fuels for EfW plants where some of the energy that was expended in manufacturing the product in the first place is converted to electric power.




5 – Reject (disposal to landfill)

Landfill sites consist of depositing waste in holes in the ground which is compacted and covered with earth. Different waste fractions decompose over different time periods and in the process produce carbon dioxide, methane and numerous other trace gases. If these gases are not collected and removed, they will either leak into the atmosphere or, in some circumstances, create explosive conditions in the landfill site. Dangerous liquids may also be discharged into the surrounding water table.Rethinking the Waste Hierarchy



5 – Reject (disposal to landfill)

The UK is reluctantly phasing-out landfill sites, partly because it is running out of suitable landfill sites and partly because of the European Landfill Directive (2002) which will require the organic fraction of landfilled waste to be reduced by 25% by 2010, 50% by 2013 and 65% (all below 1995 levels) by 2020.



How is the UK doing?



Is the ‘Waste Hierarchy’ working?

As we have seen, the ‘Waste Hierarchy’ has some basic flaws:

The first priority (Reduce) has to be contrasted with an annual growth in waste arisings of c.3% per annum.

The second priority (Re-use) has had only limited success in a ‘throw-away’ society.

The third priority (Recycle) has been given an artificial importance by recent legislation:Rethinking the Waste Hierarchy


CO2 Impact for Glass

CO2 Saving

kg/t

Reduce c.843

Re-use 550

Re-cycle (closed-loop) – UK 314Re-cycle (closed-loop) – Export 290Re-cycle (open-loop) – Bricks 66Re-cycle (open-loop) – Gl. Fibre 275Re-cycle (open-loop) – Shot Blast 19Re-cycle (open-loop) – Filtration -43Re-cycle (open-loop) – Aggregates -2

Landfill Disposal 0


‘Waste’

Priority

Source: Oakdene Hollins and Enviros


Is the ‘Waste Hierarchy’ working?

It is evident that blindly following current recycling legislation can lead to a situation which is absurd.

Every example of ‘recycling’ needs to be analysed to ensure that the process is genuinely solving the problem (e.g. reducing CO2 emissions) and not exacerbating it.

In any case, why should we continue to regard ‘waste’ as a problem; why not a ‘resource’?Rethinking the Waste Hierarchy


CO2 Impact for Glass

CO2 Saving

kg/t

Reduce c.843

Re-use 550

Re-cycle (closed-loop) – UK 314Re-cycle (closed-loop) – Export 290Re-cycle (open-loop) – Bricks 66Re-cycle (open-loop) – Gl. Fibre 275Re-cycle (open-loop) – Shot Blast 19Re-cycle (open-loop) – Filtration -43Re-cycle (open-loop) – Aggregates -2

Landfill Disposal 0


‘Waste’

Priority

Source: Oakdene Hollins and Enviros

‘Resource’Priority


‘Waste’ or ‘Resource’?


“The past 12 months have continued to show the denial and disconnected thinking with which the Government, businesses and the public approach the subject of waste. In this country, waste is seen as an end – a dead end – rather than a means. That view has to change.”

“State of the Nation” Report - ICE (October 2005)




“Waste is a combination of materials – our resources for tomorrow. If we extract reusable materials, what’s left is residual waste – solid material containing energy that can be released to light rooms, heat buildings and drive businesses.”





“A report published by ICE and the Renewable Power Association measuring the potential energy from residual waste estimated that, by 2020, 17% of all electricity could, theoretically, come from waste. A more realistic but still very significant contribution would be 10%.”



In some cases, the energy required in the recycling process (especially when separation, collection and transport are taken into consideration) is greater than the energy required to make the product from raw materials. This appears to be particularly true in the case of recycling paper, for example. On the other hand, many waste products can be excellent fuels for EfW plants where some of the energy that was expended in manufacturing the product in the first place is converted to electric power. In each waste case, an energy balance should be made to calculate the net benefits of recycling or recovery.

Isn’t it always better to ‘recycle’ than ‘burn’?



Definition of ‘Incineration’

Having looked at the abuse in the UK of the English words ‘waste’ and

‘recycle’, let’s now look at the most misused word of all in this field:

‘Incineration’

All ‘Energy-from-Waste’ plants in the UK now, by law, regardless of the

actual technology, must comply with the absurdly named ‘Waste

Incineration Directive’!Rethinking the Waste Hierarchy


Most people in the UK do not know the difference between ‘incineration’ and ‘combustion’. The term ‘incineration’ stems from the outdated method of

burning municipal solid waste (MSW) in order to destroy it. This thinking, in turn, derives from seeing waste as a

‘problem’ rather than as a ‘resource’; there is a particular issue here, in that

the UK Government is itself very unclear on this subject! DEFRA constantly refers

to EfW plants as ‘incinerators’ and despite public ‘consultation’ on this issue appears to have ignored the

feedback!

Is EfW a euphemism for Incineration? - 1



• Incineration is the process of ”burning up completely” or “reducing to ashes” - i.e. the emphasis is on destruction of the material, or at least the organic fraction;

• Combustion is “the process of burning” or “any process in which a substance reacts to produce a significant rise in temperature and the emission of light” or “a process in which a compound reacts slowly with oxygen” – i.e. the emphasis is on the (chemical) reaction taking place in the process.

Collins Concise Dictionary, Fourth Edition, Harper Collins,1999




• Incineration is “a volumetric waste reduction process that relies on combustion under suitable controlled conditions to reduce the volume and/or mass of [waste] material for disposal” – i.e. the emphasis is on the disposal.

• Combustion is “a chemical reaction in which fuel combines with oxygen with the evolution of heat” – i.e. the emphasis is on the chemical reaction.

Prof Andrew Porteous, Dictionary of Environmental Science and Technology, Third Edition, John Wiley &

Sons, 2000




Examples of modern Energy-

from-Waste (EfW) Plants.

Stoke on TrentStoke on Trent

BillinghamBillingham

If these areIncinerators…



…then please describe this

as a Coal Incinerator!

Drax Coal-FiredPower Station,

North Yorkshire –3,400 MW from

largely importedfossil fuels.



Peterborough Gas-Fired CCGT Station –Peterborough Gas-Fired CCGT Station –380 MW from increasingly imported fossil 380 MW from increasingly imported fossil

fuels.fuels.

… … and this as a Gas Incinerator!and this as a Gas Incinerator!



1) Direct Combustion

Most developed countries recognise the important contribution which can be made to EfW by the simplest, cheapest and, often, most efficient method of energy conversion, i.e. Direct Combustion.

Modern combustion plants have overcome most of the problems associated with older ‘incinerators’ and it is strange indeed that it is not included among the Advanced Conversion Technologies (ACT)! From a technical standpoint, this makes no sense whatsoever and this situation should be urgently reviewed.

State-of-the-art in energy conversion - 1



Heat

Feed Steam turbine

Boiler

Direct combustion Solid organic fuel Components: boiler, steam turbine Proven technology Highly reliable




San Ouen, ParisSan Ouen, Paris

Rotterdam

Some European examples of Direct Combustion:




2) Pyrolysis

Pyrolysis is the thermal degradation of organic waste in the absence of oxygen to produce a carbonaceous char, oils and combustible gases. Although pyrolysis is an age-old technology its application to biomass and waste materials is relatively recent. An alternative term for pyrolysis is thermolysis, which is technically more accurate for waste energy processes because these systems are usually starved-air rather than the total absence of oxygen. Although the future for pyrolysis is extremely promising, there is as yet little direct operating experience with this method.




Pyrolysis

Feed

Liquid Solid Gas

Bio-oil (medium temp/short time)

75 12 13

Charcoal (Low temp/long time)

30 35 35

Fuel gas (high temp./medium time)

5 10 85

• solid organic fuel• absence of oxygen• thermal degradation





Compact

Power

Pyrolysis/

Gasification

System

3 High TemperatureOxidation

1 Pyrolysis

4 Energy Recovery

2 Gasification



3) Gasification

Gasification differs from pyrolysis in that oxygen in the form of air, steam or pure oxygen is reacted at high temperature with carbon in waste to produce a gas, ash or slag and a tar product. Although gasification is very recent in its application to waste, coal gasification of coal, is well proven. Major benefit of gasification is that product gas is used directly to fuel a gas turbine generator which forms part of a CHP or CCGT system, improving overall thermal efficiency. Main disadvantage is high capital investment and lengthy pay-back periods.




Gasification

Gas turbine

Gas engine

Syngas

Feed

• Solid organic fuel / gas from pyrolysis

• Partial oxidation

• Fuel gas: CO / CO2 / CH4 / H20

• Reduced NOx / dioxin formation

Gasifier


Heat




GlobalOlivineHigh

Temperature

Combustion/

GasificationSystem

CombustorUHTC



3) (Anaerobic) Digestion (AD)

AD is commonly used with liquid and semi-liquid slurries such as animal waste; it is also used for obtaining gas from human sewage but is now being applied to certain biomass wastes. Digestion utilises the same biological processes as a landfill but under controlled conditions in a digester system, which is a warmed, sealed, airless container where bacteria ferment organic material in oxygen-free conditions to produce biogas. Amount of biogas is limited by the size of the digester tank so is used as fuel in a gas boiler or in an engine to generate electricity.




Digestion

Digester

Gas turbineBiogas

Feed

• Liquid organic fuel

• Anaerobic

• CH4/CO2 fuel gas

Gas engine


Heat



Typical DigesterSystems

Large-scale Digester Gas Storage Tank

Small-scaleFlexible Liner Digester




The growing problem of The growing problem of Waste which cannot be Waste which cannot be

landfilled.landfilled.PREP can handle all of these!PREP can handle all of these!

Proposed Peterborough Renewable Energy Plant



Typical Fuel Input for PREP (1 million t/y):

Industrial/Commercial Waste410,000 t/yMunicipal Solid Waste (MSW)300,000 t/ySewage Sludge 90,000 t/yVehicle Tyres 30,000 t/yOil/Thinners (after recycling) 20,000 t/yLocally-grown Biomass150,000 t/y




Normal Annual Outputs: 126 MW Electric Power NETT! (>1.0 TWh) Up to 58,000 m3 Concrete 145,000 t Aggregates – block products 2,500 t Non-ferrous metal ingots 30,000 t Iron & Steel 50,000 t Glass Products (tiles, filtration,

enamel etc) 12,000 t Hydrochloric Acid Up to 4000 tonnes Pure Sulphur Up to 2 tonnes Pure Mercury 725,000 MWh Renewable Obligation

Credits 1,300,000 tonnes Carbon Credits ZERO output to landfill!




Will PREP ever be built?

After 5 years of immensely hard work, we seem to have made hardly

any progress.Often we feel like giving up but we are encouraged by the thoughts of

Mahatma Gandhi:

“First they ignore you,Then they laugh at you,

Then they fight you,Then you win!”



Rethinkingthe

‘Waste Hierarchy’

Thank you for your attention during this presentation.


“Materials for a Greener Environment”01 November 2005IMechE HQ, London

engineered solutions international rethinking the ‘waste hierarchy’ euring ian m. arbon msc,...

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