Anaerobic co-digestion of poultry droppings and briquetted wheat straw at mesophilic and thermophilic conditions: Influence of alkali pretreatment.

Anaerobic co-digestion of poultry droppings (PD) and briquetted wheat straw (BWS) with alkali additive in the form of KOH (BWS add ) or without any additive (BWS raw ) was conducted using continuously stirred tank reactors (CSTRs) under both mesophilic (35 °C) and thermophilic (53 °C) conditions. The aims of the study were to compare 1) co-digestion of PD and BWS versus mono-digestion of PD; 2) co-digestion of PD and BWS with or without additives; and 3) mesophilic and thermophilic anaerobic digestion (AD). Co-digestion of PD and BWS was superior to mono-digestion of PD in terms of gas production. Co-digestion of PD with BWS add at thermophilic temperatures resulted in a higher methane volumetric yield per kg substrate compared to mesophilic conditions. With and without additive, co-digestion with BWS produced 8% and 11% higher yields at thermophilic conditions than at mesophilic conditions. Co-digestion of PD with BWS add resulted in, respectively, 14% and 27% more methane produced at mesophilic and thermophilic conditions over mono-digestion of PD. When mono-digesting PD, the mesophilic temperature was superior to the thermophilic since methane yield was higher in the mesophilic temperature regime. [ABSTRACT FROM AUTHOR]