Our In-Vessel Composting facilities

We operate two in–vessel Composting Plants at Etwall in Derbyshire and Ufton in Warwickshire, processing approximately 100,000 tonnes of co-mingled green waste per annum. The feedstock for these plants comes from kerbside collections for Warwickshire and East Staffordshire councils. We divert garden waste away from landfill to lift local recycling rates while converting the waste into compost and soil conditioners and using it to restore landfill sites. This naturally benefits the environment.

The In-Vessel Composting process

Our facilities are based around a reception building, feedstock preparation area, a number of concrete composting tunnels, a compost maturation pad, and air handling equipment. Here is a breakdown of the in-vessel composting process:

• Incoming wastes are sorted, shredded to achieve a maximum particle size, mixed to achieve the correct “recipe,” and then loaded into composting tunnels.
• Air is drawn through the feedstock with the rate of air flow being controlled to ensure an optimum treatment temperature.
• Following the completion of an initial composting period, the material is removed from the tunnel, remixed and returned to another tunnel for the composting process to be completed.

The treated material is then stored for a period of 4 to 8 weeks to enable final maturation to occur, whereupon the product is screened and sieved to remove any contamination. We are able to achieve a variety of material grades that depend on the final end-use.

Other Composting processes - Open Windrow Composting

The main differences between composting systems largely relate to scale and whether the process occurs in the open or is enclosed (in-vessel). Most small-scale domestic composting systems operate only for short periods at high temperatures, and then become cold quite quickly, with the overall process often taking many months to complete. Larger scale systems, where the material is mechanically turned to form a windrow, are more efficient, but are only suitable for green waste. Biffa also offer this service through our Open Windrow Composting facilities in Kilsby, Skelton Grange, and Meece.

They are, however, used extensively throughout the UK for the treatment of garden waste. In-vessel systems have the advantage of operating at optimal temperature and moisture conditions; because they are enclosed can accept for treatment a wider range of organic materials, including food waste, for treatment. An additional advantage is that air from the composting process, which can be malodorous, can be captured and treated.

If you’d like to learn more about the in-vessel composting services we offer, or you’d like advice and guidance on how this could help, please get in touch with our team.