Use of Methanogenic Activity Tests to Characterize Anaerobic Sludges, Screen for Anaerobic Biodegradability and Determine Toxicity Thresholds against Individual Anaerobic Trophic Groups and Species

A variety of test procedures have been reported in the literature for determination of the specific methanogenic activity profile of anaerobic sludges and for screening synthetic organic chemicals for anaerobic biodegradability. This paper reviews the methods developed and presents data obtained in the authors' laboratory using test procedures based on pressure transducer measurement of gas pressures in sealed anaerobic vials. Data on the feasibility of freeze-drying granular sludge are also presented as part of a wider study concerning the development of a standard reference sludge for anaerobic biodegradability testing. The use of the methanogenic activity test method to assess the relative toxicity of compounds, known to inhibit methanogenesis, against individual trophic groups involved in the overall digestion process is also described.