Anaerobic Digester Foaming: Causes and Solutions

摘要

Anaerobic digester foaming has often plagued operators of wastewater treatment plants(WWTPs). Due to the complexity of the problem and the variables involved, it is often difficultto correctly identify the cause of the foaming. Foaming in conventional anaerobic digesters hasbeen attributed to a number of causes from inadequate mixing to Nocardia bacteria carried overfrom the secondary treatment process. However, causes identified in the literature can begrouped into three main categories. Each of which are discussed separately with their respectivesolutions.Foaming in advanced digestion processes has not been well studied, and is a complex problem atWWTPs and can be caused by a variety of factors or combination of factors. Informalinterviews were conducted with several municipalities regarding anaerobic digester foamingoccurrences and operational strategies to deal with the problem. No universal solutions werefound, but site- and system-specific solutions were common. The paper also includesrecommendations for designers of digestion systems and a decision-tree for operators dealingwith foaming problems.