The Environment Agency conducts continuous emissions monitoring and regular independent checks.
We use a variety of control and treatment processes to ensure gases created during the burning process are cleaned and filtered.
As well as enabling us to send these items on for recycling, it also ensures that waste is mixed. This is helpful in providing a consistent fuel for the EfW process and maximising efficiency.
We also keep the temperature below 1300°C and control oxygen levels to reduce the levels of nitrogen oxide.
Urea is injected to break down the nitrogen oxides produced during good combustion and convert them to nitrogen and water
Hydrated lime is injected to neutralise oxides of sulphur and hydrogen chloride and to reduce acidity
Activated carbon is injected to trap heavy metals and any remaining dioxins
Particulate Matter is the term used to describe tiny particles in the air which are made up of a mixture of soot, organic and inorganic materials. These are smaller than or equal to 10 microns or 100th of a millimetre in diameter.
There are many man-made and natural sources of particulate matter including road transport, industry, volcanoes and dust storms.
Gases created during the combustion process are filtered through a bag filter system consisting of 350 ‘bags’ which trap the fine dust.
TOC is part of a large group of liquids and gases known as Volatile Organic Compounds (VOC). These are gaseous and can vaporise at room temperature. They can also react with other gases such as Nitric Oxide to form ozone at low atmospheric levels – high concentrations of this can be harmful to humans.
Paints, natural gas, petrol, road transport and industrial processes are the major sources of these compounds. However, some are also produced by natural biological processes.
Organic chemicals are widely used as ingredients in household products. Paint, varnish and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while you are using them and, to some degree, when they are stored.
By ensuring that waste is burned for two seconds at 850°C.
CO occurs naturally and is also manufactured during industrial processes. It is a colourless, odourless, poisonous gas.
CO is released by vehicle exhausts and small amounts are released through the burning of fossil fuels in power stations and EfW facilities.
Our combustion controls ensure that waste is burned at 850°C for two seconds. Getting the right combination of heat and oxygen reduces CO concentrations.
HCl occurs naturally and can be manufactured. It is an acidic, corrosive, colourless gas with a pungent smell.
The main sources of HCl are coal-fired power stations; small amounts are released from EfW facilities.
Our flue gas cleaning system injects hydrated lime and activated carbon to eliminate HCl.
SO2 is a colourless gas with a strong smell; it can occur naturally or be created.
SO2 is produced by burning coal and oil, typically by power stations and oil refineries. It is also created by any open fire and can also be released naturally from forest fires and volcanoes.
Hydrated lime and activated carbon are injected into the flue gas network to neutralise it.
Dioxins and furans are related types of complex chemicals containing chlorine. There are several hundred dioxin substances. They are crystalline when solid and dissolve in solvents, fats and oils but not in water.
They can be released as by-products from the burning of fuels, including waste. Some industrial processes including metal processing and paper manufacturing also create them. They are found in cigarette smoke and are released naturally from volcanoes and forest fires.
We minimise the formation of dioxins and furans by burning waste for at least two seconds at 850°C. Any remaining small amounts are absorbed into the activated carbon that is injected into the flue gas network of pipes.
The reaction product is a dry solid material known as Air Pollution Control Residue (APCR). This is separated by means of the fabric filter from the gas stream and disposed of off-site at a suitable treatment facility.
