Case Studies » NVP Energy UK Ltd
A request was made by NVP Energy UK Ltd, to consider compliance with the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) for their Anaerobic Digester project at Bairds Malt, Arbroath Facilities. In 2020 the wastewater treatment plant were being upgraded, the new facilities and infrastructure needed to be risk assessed. The DSEAR focus was primarily upon arrangements for potentially hazardous Bio-gas flammable gas accumulations that may arise.
Anaerobic digestion (AD) process utilises natural bacteria to breakdown biodegradable materials in the absence of oxygen and forming methane-rich biogas which is captured as a source of fuel for power and heat. Operations at the site will therefore routinely generate material in significant quantities that may require DSEAR controls.
The Solution Provided
Thousands of tonnes per year of feedstock into the Bairds Malt AD project will produce large quantities of biogas which is generally made up of around two-thirds Methane and one-third Carbon Dioxide – with trace amounts of Ammonia or Hydrogen Suplhide. The exact Biogas composition varies with the type of feedstock but in any case the Methane concentration can be increased prior to combustion and use as a source of energy.
In DSEAR terms digestate by-product from the AD process is not hazardous but Methane is extremely hazardous and flammable or explosive atmospheres may occur without proper gas controls.
A detailed survey was undertaken of the site operations and operational procedures from which hazardous zoning was identified to management. The detailed report provided covered all aspects of control identified in the survey and a number of recommendations for improvements to the extensive safety controls employed on the site. Importantly the report covers all key parts of the DSEAR hierarchy of controls: reduction of quantities, minimisation of release, minimisation of hazardous areas through ventilation, minimisation of ignition sources, etc.