Emissions Management

Ensuring what comes out of the stacks (chimneys) is compliant

An essential part of turning non-recyclable waste into energy is combustion. When waste is combusted (burned), it produces gases (emissions) which, if left untreated, have the potential to be harmful to the environment and human health. That is why it’s not advisable to burn rubbish in your back garden. It’s also why one third of the ERF is dedicated to cleaning these gases to ensure that what’s released into the atmosphere (via the stack(s), or ‘chimney(s)’) is safe and will not harm the local environment or the health of local people.

Monitoring emissions

Emissions from the ERF are continuously monitored every 10 seconds, 7 days a week, 365 days a year. We record raw data that is used to create averages. Samples are taken from the gases in the flue stacks. The results are fed back to the ERF control room, so any potential issues are known about immediately and appropriate action can be taken.

Regulation

The emissions from the ERF are closely monitored by an environmental regulator that has been established by each of the devolved nations.  In England the environmental regulator is the Environment Agency (EA), in Wales it is Natural Resources Wales (NRW) and in Scotland it is the Scottish Environmental Protection Agency (SEPA).

Prior to operating an ERF, the environmental regulator issues an Environmental Permit to the site that prescribes limits for different types of releases to air, water and land. If any of these limits are breached, Viridor must notify the EA/NRW/SEPA within 24 hours of the event.

The Environmental Permit held by Viridor also requires the ERF to submit quarterly emissions monitoring reports to the regulator. In the event of issues or problems, the regulator has a range of powers at its disposal, ranging from advice and guidance to prosecution and revocation of the sites Environmental Permit that would prevent it from operating.

The ERF has been designed to operate at the very highest international standards.

Providing local people with reassurance

Viridor and our local authority partners recognise that the safe operation of the ERF is a very important issue for people who live in the surrounding areas.

To provide reassurance that the ERF is operating safely and does not pose a threat to human health or the local environment, environmental reports are made available on the Public Register held and administered by each environmental regulator.

Which emissions are monitored?

The following emissions are monitored on a continuous basis at the ERF as they are all a product of the combustion process:

• Dust (Particulates) - Particulate Matter is generally categorised on the basis of the size of the particles. It is made up of a wide range of materials and can arise from a variety of sources. Particulate Matter derives from both human-made and natural sources, such as sea spray, Saharan dust and volcanic eruptions. In the UK one of the biggest human-made sources of particulate matter is transport.
• Total Organic Carbon - Total Organic Carbon (TOC) is a collective term for all the gaseous organic substances that may be present in the flue gas. These substances are also often referred to as volatile organic compounds (VOCs). VOCs have both natural and anthropogenic sources. Many industrial processes emit VOCs including printing, surface coating and painting, however, households and road transport also contribute a substantial fraction.
• Hydrogen Chloride (HCl) - At room temperature, Hydrogen Chloride exists as either a colourless or slightly yellow gas. It is formed when material containing chlorine, including table salt, is burned in air. The main source of Hydrogen Chloride is old coal burning power stations.
• Carbon Monoxide (CO) - Carbon Monoxide is formed from incomplete combustion of carbon-containing fuels. The largest source is from road transport; older vehicles which do not have catalytic convertors produce significant amounts with newer cars producing very little.
• Sulphur Dioxide (SO₂)- UK emissions are dominated by combustion of fuels containing Sulphur, such as coal and heavy oils by power stations and refineries. In some parts of the UK, notably Northern Ireland, coal for domestic use is a significant source.
• Oxides of Nitrogen - All high-temperature combustion processes in air produce oxides of nitrogen (NO_x). Nitrogen dioxide (NO₂) and nitric oxide (NO) are both oxides of nitrogen and together are referred to as NO_x Road transport is the main source, but this can also be formed in lightning storms and from natural breakdown processes in soil and water.

Reducing the amount of non-recyclable waste which comes to the ERF has a positive impact on the emissions the facility is required to treat. We can all play our part to ensure that no opportunities to reduce, reuse and recycle resources are missed.

Ensuring measurements are accurate

It is vital that the specialist equipment taking gas samples from the flue stacks of the ERF are operating correctly and taking accurate measurements. To make certain this is the case, the Environment Agency, Natural Resources Wales and the Scottish Environmental Protection Agency ensures the equipment is put through a rigorous three-stage testing and quality assurance process: the regulators Monitoring Certification Scheme (MCERTS).

The second level of quality assurance calibrates the instruments. An independent and accredited test house carries out a full calibration every three to five years. In addition, each year an independent accredited test house undertakes an Annual Surveillance Test to ensure that the calibration remains valid.

Finally, Viridor regularly calibrates the monitoring equipment to ensure compliance as required by the regulations.