What are the options?

Through the market testing exercise, the partnership has received a great deal of interest from a number of companies offering different technological solutions. These solutions can be broadly split into two sections, biological processes and heat treatment processes, though as the options below indicate these can be combined.

Advanced Thermal Treatment (ATT) – Pyrolysis and Gasification

Pyrolysis treats waste between 300-850 Degrees Celsius in the absence of oxygen to produce a ‘synagas’ that can be burned to generate electricity. A solid waste is produced, which is sometimes known as ‘Char’. This is ‘hazardous waste but could be used as coal replacement in certain combustion applications or as a gasifier feedstock material’ (Defra new Technologies Supporter Programme 2007).

Gasification operates at a higher temperature above 650 Degrees Celsius. Oxygen is added but the amounts are not sufficient for the fuel to completely oxidise for full combustion to occur. A ‘synagas’ is produced that can be burned to generate electricity, the other product produced is a solid residue (slag or ash). There is a potential market to recycle this product into aggregate for the construction industry.

For a full detailed brief on ATT, please visit: Defra.gov.uk

Anaerobic Digestion (AD) + Bio Gas Production

Is the process where biodegradable material is broken down without exposure to oxygen in a closed container. As the material breaks down, ‘biogas’ is produced which is recovered and then can be burnt to produce heat and (or) electricity. Depending on whether ‘dry’ or ‘wet’ anaerobic digestion is used the average temperature that this process operates is between 30-60 Degrees Celsius.

This process can only be used to process organic matter and not man made materials.

For a full detailed brief on ABT, please visit: Defra.gov.uk

Dry Anaerobic Digester

Energy from Waste (EfW) with combined heat and power

This is the combustion of waste over 850 Degrees Celsius with sufficient quantity of oxygen to fully oxidise the fuel. The standard approach for the recovery of energy from incineration is to utilise the combustion heat through a boiler to generate steam. The steam can be used for the generation of power via a steam turbine and used for heating and power.

There are two residues produced, the bottom ash (20 to 30% of the original weight of the waste put into the plant) can be recycled into aggregate and air pollution control residues (2 to 6% of the weight of the waste entering the plant) is classed as hazardous and needs to be to be disposed of at a hazardous landfill site.

‘A combined heat and power plant is the most efficient option overall for utilising recovered energy from waste via a steam boiler’ (Defra New Technologies Supporter Programme 2007).

‘In the UK all waste incineration plants must comply with the Waste Incineration Directive (WID). This directive sets the most stringent emissions controls for any thermal processes regulated in the European Union.’ (Defra New Technologies Supporter Programme 2007).

For a full detailed brief on Incineration, please visit: Defra.gov.uk

Portsmouth Exterier courtesy of Veolia Environmental Services, Hampshire

Astria in Bordeaux

Do you want to contact us?

Prosiect Gwyrdd
PO Box 3120
Cardiff
CF30 0DA

Tel: (029) 2071 7523
E-mail: info@prosiectgwyrdd.co.uk

Did you know?

The decomposition of waste in the absence of air, gives off methane. As a molecule, methane is 23 times more potent as a green house gas than carbon dioxide.
In the UK approximately 2.4 million tonnes of methane is release each year. Emissions from municipal solid waste landfill sites account for 27% of the national total.
Methane is recovered from landfill operations, but the collection rate at best is only 10%. This has to be compared to residual waste treatment plants where the collection rates are between 40-60%.

Landfill has historically been the chosen method to deal with waste. This cannot continue and a solution has to be found.

A third of all the food we buy ends up being thrown away.
In Wales we throw away 330 000 tonnes of food waste each year.
Organic waste, such as fruit, vegetables and tea bags make up to 38% of the contents of the average dustbin.
An estimated 6.7 million tonnes of household food waste is produced each year in the UK, most of which could be eaten.

Each of the local authorities in Prosiect Gwyrdd are committed to divert as much food waste as possible for composting and plans are underway to implement new schemes.

Every year in the UK, we throw away 28 million tonnes of rubbish from households. This weighs the same as three and a half million double decker buses.
Every day 80 million food and drink cans end up in landfill.
In the UK, we fill about 300 million square metres of land with rubbish each year.
We produce 20 times more plastic in the UK than we did 50 years ago.

Each of the local authorities in Prosiect Gwyrdd is committed to recycling and composting as much waste as practically possible. Residents have a duty to reduce and reuse as much waste as possible so that we can all improve the environment. Waste is everyone's problem.

Wyddech chi?

Mae gwastraff sy'n dadelfennu heb aer yn cynhyrchu methan. Fel moleciwl, mae methan yn gallu cynhyrchu 23 gwaith yn fwy o nwyon ty gwydr nag yw carbon deuocsid.
Yn y DU, rhyddheir oddeutu 2.4 miliwn o dunelli o fethan bob blwyddyn. Mae allyriadau o wastraff dinesig solid mewn safleoedd tirlenwi yn 27% o'r cyfanswm cenedlaethol.
Cesglir methan o weithredoedd tirlenwi, ond 10% ar y mwyaf yw'r gyfradd gasglu. Rhaid cymharu hwn â gwaith trin gwastraff gweddilliol lle mae'r cyfraddau casglu'n llawer uwch (gweler y tudalen dewisiadau).

Tirlenwi yw'r modd traddodiadol o ddelio â gwastraff. Ni all hyn barhau ac mae'n rhaid cael hyd i ateb arall.

Mae un rhain o dair o'r bwyd a brynwn yn cael ei daflu yn y pen draw.
Yng Nghymru, rydym yn taflu 330,000 tunnell o wastraff bwyd bob blwyddyn.
Gwastraff organig, megis ffrwythau, llysiau a bagiau te, yw hyd at 38% o gynnwys bin arferol.
Cynhyrchir oddeutu 6.7 miliwn o dunelli o wastraff bwyd cartref yn flynyddol yn y DU, a gellir bod wedi bwyta'r rhan fwyaf ohono.

Mae pob un o'r awdurdodau lleol sy'n rhan o Broject Gwyrdd wedi ymrwymo at ddargyfeirio cymaint o wastraff bwyd â phosibl i gael ei gompostio. Mae cyllid wedi'i glustnodi gan Lywodraeth y Cynulliad ar gyfer pob awdurdod.

Rydym yn taflu 28 miliwn o dunelli o sbwriel o gartrefi bob blwyddyn yn y DU. Mae hyn yn pwyso'r un faint â thua tair miliwn a hanner o fysus deulawr.
Mae 80 miliwn o dunelli o ganiau bwyd a diod yn mynd i safleoedd tirlenwi bob dydd.
Yn y DU rydym yn llenwi tua 300 miliwn o fetrau sgwâr o dir gyda sbwriel bob blwyddyn.
Rydym yn cynhyrchu 20 gwaith mwy o blastig yn y DU nag oeddem yn ei wneud hanner canrif yn ôl.

Mae pob un o'r awdurdodau lleol sy'n rhan o Project Gwyrdd wedi ymrwymo at ailgylchu a chompostio gymaint o wastraff ag sy'n bosibl. Mae dyletswydd ar breswylwyr i leihau ac ailddefnyddio gymaint o wastraff â phosibl er mwyn i ni gyd wella'r amgylchedd. Mae gwastraff yn broblem i bawb.

Manylion Cyswllt

Prosiect Gwyrdd
Blwch SP 3120
Caerdydd
CF3 0DA

Ffôn: (029) 2071 7523
E-bost: info@prosiectgwyrdd.co.uk

Mechanical Biological Treatment (MBT)

Involves mechanical sorting to take out waste that can be sorted for recycling and composting. This is done through a variety of screens and magnets. The remaining waste is then broken down through a composting process and dried out.

The product produced from this process is called ‘compost-like outputs’ (CLO). ‘The quality of the CLO produced will vary with different MBT technologies…As a waste, these materials require a waste management licence exemption in order to be used on land. Currently they can only be used on non-agricultural land and must be shown to be ecologically beneficial.’ (Defra New Technologies Supporter Programme 2007)

For a full detailed brief on MBT, please visit: Defra.gov.uk

Hanoever MBT Dorset Stack

Lubeck MBT

Mechanical Biological Treatment (MBT) with Energy from Waste

The product which is produced after the mechanical and biological processes of MBT can be made into a ‘refuse derived fuel’ and burnt through a thermal process to generate electricity.

For a full detailed brief on MBT with energy from waste, please visit: Defra.gov.uk

Mechanical Heat Treatment e.g. Steam Autoclaving

‘Mechanical Heat Treatment is a relatively new term. It is used to describe configurations of mechanical and thermal, including steam based technologies…The waste is subjected to steam under pressure… or externally applied heat, followed by mechanical sorting and separation of the sterilised waste.’ (Defra new Technologies Supporter Programme 2007).

‘Mechanical Heat Treatments have a limited track record worldwide…The technology is in common use for the sanitisation treatment of some clinical wastes and for certain rendering processes for animal waste, prior to sending to landfill. Its application to municipal solid waste is a recent innovation and there is limited commercial experience on this feedstock material.’ (Defra New Technologies Supporter Programme 2007)

For a full detailed brief on mechanical heat treatment, please visit: Defra.gov.uk

Auto Clave

How is a solution going to be found?