Eliminating Microthrix at Denaby Activated Sludge Plant

Yorkshire Water’s 35,000 PE Denaby WWTP was built in 2008 and combined flows from Denaby, (population 6,500). Burcoft (population 11,400) and Mexborough (population 17,600). The treatment plant includes primary settlement, an anoxic tank, four activated sludge lanes and two final settling tanks.

The plant treats a flow to full treatment of up to 215 l/s and has final effluent consent requirements of 25 mg/l BOD (or 70% removal), 125 mg/l COD (or 75% removal) and 9 mg/l ammonia on a 95%ile spot sample basis, which is discharged to the River Don.

Since it was built the plant has suffered from microthrix growth and associated operational and performance issues for around six months of the year. In 2017 Aquability OPS Ltd was engaged by Yorkshire Water to determine the cause of the issues and identify and implement a solution. The changes made by Aquability have resulted in the plant achieving robust and reliable operation and performance, and to date the microthrix has not returned.

Microthrix in ASP
Microthrix eliminated following Aquability process optimisation