Inoculum to substrate ratio: Calculating methods

Abstract

Anaerobic codigestion (AcoD) is a proven option to significantly boost biogas production while utilizing existing digesters and infrastructure. Co-digestion of food waste with sewage sludge (SS) is increasingly exploited to raise energy production and make anaerobic digestion more affordable; however, there is a lack of information on appropriate codigestion ratios of substrates and inoculum. The aim of the present research was to conduct an exhaustive study regarding amounts of mixed sewage sludge and organic fraction of municipal solid waste (OFMSW) or food waste (FW). The effect of inoculum to substrate ratio (ISR) on biogas/methane production rates and ultimate yields was evaluated for biochemical methane potential (BMP) assay in an anaerobic reactor. Comparative performance was made for differently calculated concentrations of substrate and inoculum based on terms of g volatile solids (VS) substrate/g VS inoculum. Different calculating approaches were investigated and general and common formulas are given as a result of research.