Co-digestion of cow manure, food waste and intermittent input of fat

Abstract

Pulses of fat were added to completely mixed reactors fed with dairy cow manure (CM) and food waste (FW). After achieving a stable performance at an organic loading rate (OLR) of 4.6± 0.1 gCOD/(Lreactor.day), an oily effluent (OE) from a canned fish processing industry was fed in the form of pulses, raising the lipids concentration up to 9, 12, 15 and 18 gCODfat/Lreactor. The highest fat concentration of 18gCODfat/Lreactor promoted a reversible inhibition in the methane production. All the other pulses had a positive effect in the methane production. From a practical point of view, this work demonstrates that controlled intermittent inputs of fat can enhance the methane production in the co-digestion of CM and FW.