Inhibition of methane formation from municipal refuse in laboratory scale lysimeters

Changes in chemical composition and population development of key groups of bacteria (hydrolytic, acetogenic, and methanogenic) were measured in a laboratory scale simulation of refuse decomposition from the time of initial incubation through the methane production phase. Inhibition of methane production appeared to be characteristic of refuse decomposition. It was observed in 20 of 32 leachate recycle containers and all 19 control containers. Inhibition was not owing to an absence of indigenous microorganisms, toxic concentrations of carboxylic acids or cations, or insufficient ammonia. Characteristics of inhibited and successful containers are compared.