Feasibility Study of Anaerobic Co-digestion of Slaughterhouse Wastewater with Sugar Press mud for Biomethane Recovery

Abstract

Slaughterhouse wastewater (SHWW) is another most-explored proteinous substrate for biomethane recovery. However, inhibitory compounds associated with its anaerobic monodigestion (AMoD) limit its practical and industrial applications. In this regard, anaerobic codigestion (ACoD) is effectively applied to optimize system stability and methane (CH4) yield by allowing toxic compound dilution. Therefore, the current study investigated the influence of sugar press mud (SPM) as a co-substrate on the treatment performance of AD. The ACoD process was semi-continuously conducted in lab-scale continuous stirred tank reactors (CSTRs) at varied hydraulic retention times (HRTs) under mesophilic conditions (37.0±1.0°C). Subsequently, the proportions of SHWW and SPM to produce CH4 were optimized in batch experiments at different mixing ratios. The addition of SPM enhanced CH4 yield and VS removal by 69.1% and 62.4%, respectively, at an optimum mixing ratio of 80%SPM:20%SHWW and 15 days (d) HRT. Moreover, the addition of SPM improved the AD process stability, as verified by the decreased ammonium nitrogen (NH4+-N) concentration. Results suggested that ACoD can be used as an alternative method for the treatment of these organic agrowastes for bioCH4 recovery. Furthermore, repeating the study under thermophilic conditions to examine the stability of the AD process in practice would also be a fruitful area for further work. Keywords— Anaerobic Digestion, Co-Digestion, Co-substrate, Mesophilic Condition, Slaughterhouse Wastewater