Co-anaerobic digestion of chicken manure with the addition of Cymbopogan citratus, Mentha piperita and Citrus sinensis as fly deterrent agents: Biogas production and Kinetic study

Abstract

This paper describes the co-AD of chicken manure (CM) and the effect of additives such as serai wangi (SW), peppermint (PPM) and orange peel waste (OPW) on biogas production, kinetic study, and fly alleviation potential on the digestate. The results revealed that co-digestion of CM alone produced the highest biogas (62.43 mL/gvs) and methane yield (31.12 mL/gvs). OPW and PPM inhibit the AD process as they contain limonene, while high lignin content in SW slows down the overall AD process. Modified Gompertz and Cone model were applied to predict methane yield showed less than 10% error between measured and predicted methane yield. Modified Gompertz model is preferred as it shows a higher R2 value (0.962–0.999) and lower overall root mean square error (52.6%) compared to Cone model (0.953–0.999,63.27%). AD process alone could alleviate the fly issues as elimination of flies is shown towards the digestate due to low nitrogen content.