Anaerobic digestion of waste from a slaughterhouse

•Experimental investigation of anaerobic digestion of a slaughterhouse waste.•Development of a low cost anaerobic system.•Study of effect of process parameters on reduction of COD of waste.

This paper investigates the effects of variation in the inoculum to waste ratio on the anaerobic treatment of slaughterhouse waste, and proposes a low cost anaerobic treatment system. The work was carried out using a laboratory scale packed anaerobic digester with a gas collecting chamber. The inoculum used for seeding the reactors was septic tank sludge. The operating temperature ranged from 28 to 37 °C. The experimental results indicated chemical oxygen demand (COD) removal efficiencies ranged from 60 to 90% and increased with increasing inoculum to waste ratio beyond (1:1). The decrease in the temperature (from 37 to 28 °C) reduced the COD removal efficiency from 90 to 75%. The system did not show any sign of destabilization under intermittent mode of operation of the reactors.