- Waste generation
- Waste Hierarchy
- Landfill Regulations
- Recovering energy from waste

Waste generation

As noted in the Waste Strategy for England 2007, the English are living beyond their environmental means. WWF have calculated that if every country consumed as many natural resources as are consumed in England then three planets would be needed to support us. Couple this with the fact that most useful products at some stage become a waste item to be disposed of then we face a real challenge.

The UK Government notes that better management of waste can contribute to:

• Reducing greenhouse gases – notably methane from landfill sites but also carbon dioxide emissions (through re-use and recycling)
• Improving resource efficiency – saving energy and reducing material use through waste prevention, re-use, recycling and renewable energy recovery
• Protecting public health through safe management of potentially hazardous substances
• Protecting ecosystems (soils, groundwater, emissions to air)
• Safeguarding social amenity – by ensuring household waste is collected, reducing fly-tipping by households and businesses, and limiting local nuisances from waste facilities.
   

Waste Hierarchy

The diagram below shows ‘the waste hierarchy’. The hierarchy incorporates the concept that ‘Reduction’ (prevention/minimisation) is better than ‘Reuse’, which in turn is better than ‘Recycling’, which is in turn is better than recovering energy by incineration which, finally, is better than disposal to landfill.

The Waste Hierarchy

Landfill Regulations

The EU Landfill Directive (99/31/EC) was introduced in 1999 in response to the fact that some Member States still disposed to landfill more than 80% of their national waste. The Directive is intended to prevent or reduce the adverse effects of the landfill of waste on the environment, in particular on surface water, groundwater, soil, air and human health.

Among other targets, the EU Directive obliges Member States to progressively reduce the amount of organic waste going to landfill to 35% of 1995 levels by 2020.

The Waste Strategy for England 2007 considers that “reliance on landfill is already reducing and this should become the home of last resort for waste” (pg46). However, Government also recognise that landfill may continue to have a place for disposal of certain hazardous waste.

An important fiscal measure which is aimed at providing incentives for companies to reduce, reuse or recycle more is the landfill tax, and the associated tax escalator. The landfill tax is paid on every tonne or waste tipped into landfill sites – the revenues being spent by Government on waste reduction programmes. The escalator provides an acceleration of the tax to provide greater incentives for businesses to find alternatives to disposal.
 

Recovering energy from waste

There are several ways to recover energy from waste:

• Anaerobic digestion – A naturally occurring process of decomposition and decay, were organic matter is broken down to a simpler chemical component under anaerobic conditions (without oxygen). See our Anaerobic digestion factsheet
• Incineration (direct combustion) – The controlled burning of municipal solid waste to reduce waste volume and to produce energy
• Secondary recovered fuel – The recovering of energy from waste that cannot realistically be reused or recycled from mechanical and biological treatment processes
• Pyrolysis – The heating of waste to high temperatures to break down any carbon content, through an absence of air to a mixture of gaseous and liquid fuels and solid residue
• Gasification – The conversion of the carbonaceous content of a material through high temperature partial oxidation into a gas stream comprising essentially carbon monoxide, hydrogen and methane
• Plasma arc heating - Municipal solid waste is heated to very high temperatures (between 3,000-10,000°C) using a plasma arc. Energy is released by an electrical discharge in an inert atmosphere. This converts the organic waste into a hydrogen-rich gas and non-organic waste into an inert glassy residue

Each technology requires different feedstocks, has different carbon emissions, outputs and efficiencies (see link below for a summary guide on energy from waste technology’).

The Waste Strategy for England 2007 considers that “recovering energy from waste which cannot sensibly be reused or recycled is an essential component of a well-balanced energy policy, and most of our European competitors already pursue this vigorously. Denmark, for instance, derives 3.6% of its electricity supply from municipal waste” (pg 76).

Using waste as fuel can have important environmental benefits:

• It can provide a safe and cost-effective disposal option for wastes that would otherwise present significant disposal problems
• It can help reduce CO₂ emissions through the displacement of fossil fuels and also improve energy security
• Methane emissions from landfill can be avoided

In terms of what should be incinerated, different waste types have different calorific values (see Table). For example, power generated from mixed plastics waste represents a calorific value similar to coal.

Potential energy of different household waste compared with solid fuels

(SOURCE: Assure – Energy from Waste fact sheet)

The Association of Plastics Manufacturers in Europe (APME) estimates that if all the EU plastic waste which is not feasible to recycle were turned into energy, it would be equivalent to at least 17 million tonnes of coal. This would represent 15% of the total EU coal imports and approximately 5% of EU energy needs for power generation.

Whilst just 10% of pre-sorted EU municipal waste would cover 5% of EU energy needs, saving up to 14 million tonnes of oil per year. (Assurre – Energy from waste fact sheet 1)