Envirocare were commissioned to undertake Environmental Permitting Regulations (EPR) compliance emission monitoring at a Wastewater Treatment Works in South Wales.
At the wastewater treatment works, part of the process on-site involves producing biogas from sewage sludge using Anaerobic Digestion. The biogas produced is combusted in up to three spark ignition engines (nominally 4.6MW combined output). The engines are used to provide power to the site, with any excess exported to the grid and to raise steam (using supplementary waste heat boilers) used in the digestion process.
As the facility is regulated by the Environment Agency under EPR, the operator contracted Envirocare to undertake emissions monitoring from the exhaust stacks serving the engines. Emissions of combustion gases and VOCs are strictly regulated as the combustion process has the potential for significant releases of air pollution from poorly set-up systems.
Using real-time data analysis Envirocare was able to inform the operator of pollutant emission concentrations on-site. This allowed site engineers to make alterations to the system to be made there and then to minimise the pollutant emissions to atmosphere.
As well as demonstrating compliance, having real-time data allowed tweaks to be made to improve the engines set-up. For a process that operates continuously 24 hours a day, 365 days a year, even a very modest improvement in emission concentration can lead to a significant reduction in pollutant mass emission over a year.
Envirocare calculated that the amount of exhaust gas released by the three engines over a one year period was approximately 148,000,000m3. By providing data to allow engineers to optimise the engines, the operator was able to reduce the concentration of Oxides of Nitrogen by over 200mg/m3 (accumulated across three engines). This reduced the mass emission of Oxides of Nitrogen from the plant by almost 10Tonnes per year.
Envirocare is an accredited Stack Testing and Occupational Hygiene services provider with a team of expert consultants.