Performance of anaerobic rotating biological contact reactors using wood and plastic support media

Abstract

Anaerobic digestion of screened dairy manure in anaerobic rotating biological contact reactors at 35°C was investigated. Reactors using discs made of cedar wood and acrylic plastic were used. The reactor with cedar wood discs had a shorter start-up period than one utilizing acrylic plastic discs. Within an operational period of 3 months, the highest methane production rate of 1.67 l CH₄ l⁻¹day⁻¹ was obtained at 1 day hydraulic retention time for the reactor with wood media. Anaerobic rotating biological reactors using plastic media gave the highest methane production rate of 1.89 l CH₄ l⁻¹day⁻¹ at 1 day hydraulic retention time after an operational period of 10 months. The results have demonstrated that anaerobic bacteria readily adhere to and develop into a bacterial film on rotating discs made of cedar.