Experiences of recommissioning acid phase digestion at Claymills STF: PRESENTATION ONLY
Charlotte Went, Severn Trent Water, UK
(Free)
WHAT IS ACID PHASE DIGESTION
The bacteria responsible for the first two stages prefer an environment of pH5 and a short retention time.
Benefits include:
• Greater gas production from greater VS destruction.
• Improved log reduction in E.Coli.
• Improvements to the stackability of the cake.
ACID PHASE DIGESTION IN STW
• Four acid phase digestion sites (APD) sites across the Severn Trent (ST) fleet.
• Derby, Claymills, Wanlip and Worksop.
• Derby was the first ST APD site commissioned in 2009.
• Two concrete APD tanks that could be operated in series or parallel.
• The three other sites (Wanlip, Claymills and Worksop) share the concentric (Bagel) design.
• Concentric Design allows for optimum mixing and ensured the hydraulic retention time.
• Smaller footprint.