Health and emissions
This document describes the atmospheric emissions from a modern energy from waste (EfW) facility.
The document explains what the emissions are, how they are controlled and their impact on human health.
What are the emissions from the site?
By far the largest products from an energy from waste (EfW) process are carbon dioxide and water vapour. These are released to the atmosphere under controlled conditions and do not cause any harm.
Other products arising from the production of energy include ash and particulates, the acid forming gases (including nitrogen oxides, sulfur oxides and hydrogen chloride), as well as dioxins. Each of these emissions is strictly controlled, and the control methods are set out below.
How would the emissions from the site be controlled?
All facilities must operate within strict control limits set by the European Union and enforced by the Environment Agency.
Modern EfW plants must be designed and operated to minimise the production of pollutants. They must be built with substantial pollution monitoring and control systems. These prevent almost all of the potential harmful emissions from the facility.
The operating conditions and emissions from the process are monitored continuously all day, every day and are recorded
Fly ash containing the majority of potentially harmful chemicals is trapped in air filters and safely removed from the exhaust air before it is released to the atmosphere.
Particulates are tiny pieces of dust and are also trapped in the air filters.
Acid forming gases are removed by controlled chemical reactions in the pollution control system (flue gas treatment system).
Dioxins are largely prevented from forming by the design of the plant which is intended to ensure complete combustion. Any that are formed are trapped almost entirely in the air filters.
What does the stack do?
It is necessary to have a stack to ensure that the very small amounts of pollutants that are released to the atmosphere are dispersed as quickly and effectively as possible. This ensures that the emissions are soon indistinguishable from the background.
The minimum stack height is approved by the Environment Agency to ensure that effective dispersion of pollutants and the minimum health impact is achieved.
Do I need to worry about the health impacts?
Recent independent studies have found that the impact of modern waste to energy plants on human health cannot be measured.
Opponents of new facilities use examples of the measured emissions from before the year 2000 when the emissions standards were lower than now to show that energy from waste plants are harmful.
This is misleading as all the plants that were operational at that time have either closed or undergone significant upgrades to operate to a much higher standard.
Ramboll reports on Health Impact Study and Flue gas treatment technology.