Understanding and Controlling Foam in Anaerobic Digesters: Three Full-Scale Case Studies

摘要

Anaerobic digester (AD) foaming is a common problem in wastewater treatment plants(WWTPs). This study attempts to understand the causes and control mechanisms of AD foamingby completing full-scale studies at three municipal WWTPs located in the Midwest. TheWWTPs chosen for this study are each unique in their process and foaming problems, howeverfacilities with non-biological foaming were targeted. The full-scale studies included a detailedevaluation of each plant and various targeted operational modifications. The followingoperational parameters were evaluated, among others, and adjustments implemented to mitigatenuisance foaming: mixing frequency and intensity, feed rate and duration, waste activated sludgeto primary sludge (WAS:PS) ratio, and foam suppression equipment.