Proceedings

In previous years we have presented HYBACS (hybrid activated sludge) as a method to double the capacity of an existing activated sludge plant, and we have presented various case studies to illustrate the key points. This year we propose to present some data and a case study for a novel application: enhancing biological nutrient removal.

Both denitrification and biological phosphorus removal require sufficient readily-degradable carbon for effective nutrient removal. The HYBACS (hybrid activated sludge) process enhances the rate of hydrolysis, liberating more readily-degradable carbon and boosting N and P removal performance. Data from a pilot trial successfully showed enhanced P removal at low carbon:P ratios and Severn Trent are now proposing to implement the method at full scale to improve biological phosphorus removal at one of their AMP7 schemes.