INCINERATION, LANDFILL… WHAT DOES MY GEOCONSCIENCE SAY?

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INCINERATION, LANDFILL… WHAT DOES MY GEOCONSCIENCE SAY? H. B. MOTTRAM Landfills Landfill sites are often seen as a threat to the environment. In truth, the UK has a good record when it comes to using landfill sites: a) if sites are well designed and well constructed then any risks can be managed and mitigated, b) we were, and still are, much better at “policing” landfill sites than our European colleagues, c) for each modern landfill there is a financial bond in place with the Environment Agency. The Environment Agency can therefore ensure that pollution or nuisance from gases and leachate can be dealt with for some 50 years after a site has closed.

Landfill sites produce methane during part of their lives. Methane is 21 times more damaging to the ozone layer than is carbon dioxide. However, a lot of this methane is captured and losses of methane are considered to account for only 3% of the UK’s total greenhouse gas emissions.

Nonetheless, the number of active landfills in the UK is continuing to fall.

Data for England & Wales: 1975 c. 4,150 1995 c. 3,000 2005 c. 1,260 2010 c. 400?

There are two causes for the dramatic change that is currently taking place: a) the European Groundwater Directive prevents new landfill sites and extensions of existing ones on major aquifers such as the Chalk. We are therefore running out of space. b) we are required to use other ways of managing wastes.

Seeing wastes in perspective Traditionally data has poor been throughout Europe. There has been a vast improvement in the last couple of years but there is still slowness in collation and release of data and in its accuracy and consistency. We also need to be wary when making comparisons as to whether the data relates to the UK, England & Wales or just England.

The total quantity of waste produced in the UK is c. 335 million Tonnes/yr (source DEFRA). Two thirds of this is what is referred to as Non-Controlled Waste (that doesn’t mean we can do what we like with it). One third is Controlled Waste which is highly regulated. It is important to note this split as the focus to date through recycling targets, packaging regulations etc. only applies to the Controlled Wastes. See Fig. 1.

In particular, most focus has been placed on household (domestic) waste yet this only represents 28% of Controlled Wastes (or 10% of Total Wastes).

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Uncontrolled Wastes 220 million Tonnes/yr

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Million Tonnes/yr

Controlled Wastes 115 million Tonnes/yr

Figure 1. Quantities of Wastes by Type There are about 24 million households in England & Wales each of which turns out an average of 22 kg/wk (just over 1 Tonne /yr). bioDegradeable ……………… inert

…….…. calorific value ………..

8% vegetable & putrescible (garden & kitchen) waste 28% paper & cardboard, 1% rags (textiles) 1% plastics 4% unclassified (difficult to sub-divide) 23% dust (household sweepings & fine ash) 11% metals 13% large cinders (still a lot of coal fires in use) 11% glass

Figure 2. Composition of Household Wastes c. 1970, Ipswich Area (Source – LGORU) biodegradeable

………………

Inert ………………. “difficult”

20% garden waste ……….. 17% kitchen waste calorific 2% nappies value 18% paper & cardboard 5% wood 3% textiles 9% household sweepings (fine, difficult to sub-divide) 8% plastics ……….. 7% metals 3% soil 7% glass 1% paint, asbestos, oil, fridges, other electricals

Figure 3. Composition of Household Wastes c. 2007, National data (adapted from WRAP)

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Managing Wastes – Waste Composition To find appropriate solutions to managing wastes we need to understand what it is that we have got to deal with. Again, most of the work has concentrated on household wastes. It is also interesting to note that what we produce has changed with time and may continue to do so. See Figs 2 and 3.

Knowing what waste types, i.e. feed-stocks, are available has allowed technologies to be adapted to handle these wastes.

Managing Wastes – The Waste Hierarchy The various methods of managing wastes have been investigated and assessed for their effect on the environment. This has included such issues as the generation of greenhouse gases, energy balance (consumption or gain), raw material balance etc. From this it has been possible to confirm and clearly list the most to the least preferable ways of managing waste. This is The Waste Hierarchy. It has appeared in several different formats but they all show a ranking of options from reduction (minimisation), the preferred option, down to landfill, the last resort. See Fig. 4.

1.

2.

3.

4.

5.

6.

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Reduce (minimise) Re-use items e.g. wash out and refill a milk bottle Recycle materials e.g. crush a wine bottle, melt and recast as a jam jar Compost vegetable/plant materials and work into the soil Use as source of energy (directly - combustion, heat treatment, indirectly – convert waste into fuel pellets) Combustion Landfill, recover energy from methane, inerts for land reclamation Landfill waste

NB Some technologies such as MBT (mechanical biological treatment) are hybrids of 2 or more of the above processes

Figure 4. The Waste Hierarchy It is with the lower placed options that there is most residual waste to be treated or disposed.

Residual Waste – Incineration, Thermal Degradation, Heat Treatment, Energy from Waste, Pyrolosis Incineration is an established treatment method in the UK. The basic process involves the burning of waste in air but several variants have evolved form this.

About 25 years ago, incinerators that destroyed chemicals were blamed for abnormal births in cattle and there was a general outcry against all incinerators. There are probably only about 12 large plants in England & Wales that take household and commercial wastes, 4 that destroy chemicals and 40 that destroy healthcare and clinical wastes. Today, emissions are extremely tightly regulated, even on crematoria.

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The volume of ash produced is much less than the volume of waste that is consumed. In terms of weight, the ash may be around 10% of the original weight of the waste. Unless the ash can be used in land reclamation or as a part concrete substitute then landfills will still be required for the ash.

Probably a more awkward problem is that of lime used to help clean the flue gases. Spent lime is now classified as hazardous waste and so can only go to a hazardous landfill site of which there are now less than 10 in England & Wales. The closest one to Ipswich is near Peterborough.

A large modern incinerator (say 350,000 Tonnes/yr input) would cost around £140 million to set up. Half of this cost would be for the flue gas cleaning equipment. The energy output of the plant would be around 20 Mwe which would supply 30,000 households (about the size of Felixstowe with the Trimleys).

Looking at the capital and operating costs of incineration it is easy to understand that even for long-term contracts it is still relatively expensive, maybe £50 to £70/Tonne.

£/TONNE

Drivers for Diverting from Landfill – Costs Costs are the primary driver in any business. Landfill costs have risen naturally as a result of more onerous regulations but landfill tax is having a vast impact. The landfill tax was introduced to deliberately make landfill more expensive so that other methods of managing wastes would become comparatively more cost effective.

L.F. TAX GATE FEE

1970

1980

1990

2000

2010

2020

YEAR Figure 5. The Rising Costs of Landfilling Household Waste Drivers for Diverting from Landfill – The EU Landfill Directive In order to work towards improving the ozone problem and other environmental risks, the EU has introduced step improvements in diverting bio-degradeable wastes away from landfill.

Limits (by volume) are: 2010, 75% of 1995 figure 2013, 50% of 1995 figure 2020, 35% of 1995 figure (in 2020 England’s target equates to a max of 5·2 million Tonnes)

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If we fail to meet the targets then the EU will fine our Government, perhaps £180milion/yr by 2020. So how has our Government responded ? It has introduced a system (so called LATS penalties) for fining Local Authorities by £150/Tonne in respect of household waste. In fairness it has to be said that our Government has provided funding for initiatives but it takes a few years for people’s changed habits to have impact or for a new treatment plant to come into use.

Recently in “Waste Strategy for England 2007” our Government has paved the way for financial penalties and incentives to be imposed on householders.

As this will be difficult to implement and central Government is too scared of upsetting the electorate it will be left to Local Authorities to decide if and how it is done.

Additional EU Waste Framework Proposals There is a need to halt the growth of waste and then to reduce levels. There are further targets: 2012, total quantity of waste to be no higher than in 2008.

2015, ban on landfilling of paper, glass, textiles, plastics and metal – should all be collected separately.

2020, ban on landfilling of all recyclables. By 2020, 50% of household waste to go for re-use and recycling.

2020, 70% of construction & demolition and industry and manufacturing to go for re-use and recycling.

Further Reading Biffa. 2002. Future perfect. Biffa Waste Services. (A thought provoking and challenging examination of waste management issues).

DEFRA. 2006. The Environment in your pocket. DEFRA Publications, London. (An excellent annually produced source of information. Copies are free but it is more sustainable to read it off their web-site).

DEFRA. 2007. Waste Strategy for England 2007. The Stationery Office. (It can be read on their web-site).

Local Government Operational Research Unit. 1971. Report No C86, Ipswich Area Refuse Disposal Study.

Mottram H. B. (2000). Waste Disposal, in: Dixon, R. G. (Ed) Geol. Soc Norfolk 50th Anniversary Jubilee Volume. p 92–94. (Traces landfill development over time).

The Chartered Institute of Wastes Management. 2005. Special Interest Group Report – Energy from Waste, Netherlands Study Tour. IWM Business Services.

Howard Mottram The Warren Duckamere Bramford Ipswich IP8 4AH

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