Biogas Improvement by Adding Australian Zeolite During the Anaerobic Digestion of C:N Ratio Adjusted Swine Manure

Abstract

Maintenance of the ideal carbon: nitrogen (C:N) ratio with a minimum level of TAN is a key challenge for achieving maximum potential CH4 production through the anaerobic digestion process of agricultural waste such as swine manure. Biogas production can be enhanced by adding zeolite into the anaerobic digestion medium. However, the effects of zeolite addition to C:N ratio adjusted feedstock, on the digester performance is unknown. The objectives of this study were to investigate the effect of Australian zeolite on anaerobic digestion of swine manure with a C:N ratio adjusted to 30 and to determine the optimal zeolite application rate to achieve the best performance. The Australian zeolite significantly enhanced CH4 production and reduced the lag phase of anaerobic digestion in batch production. The optimal addition rate of zeolite was appeared to be around 40 g/L. The better digester performance was attributed by the reduction of dissolved ammonium from the digestate. This study indicates that Australian zeolite is an effective treatment to address problems associated with co-digestion of swine manure with different carbon sources.