Pretreatment optimization, process control, mass and energy balances and economics of anaerobic co-digestion of Arachis hypogaea (Peanut) hull and poultry manure

•Biogas was produced from the co-digestion of peanut hull and poultry manure.•Thermo-alkaline pretreatment enhanced enormous biogas yield from the substrates.•Over 70.47% gas yield was obtained with pretreatment over the untreated substrates.•The optimal condition for maximal biogas yield were established.•A negative energy balance was obtained which can be increased with higher loading. The study explored biogas production from the co-digestion of Arachis hypogaea hull and poultry droppings. Mechanical and thermo-alkaline pretreatments were applied to a sample of the mixture. Another sample was treated mechanically but without thermo-alkaline methods. Optimization was done using the Response Surface Methodology (RSM) and the Artificial Neural Networks (ANNs). The optimal values for each of the five major parameters optimized are Temperature of 32.00°C, pH of 7.62, Retention time of 30.00 day, Total solids of 12.00g/kg and Volatile solids of 10.00g/kg and the predicted biogas yield for RSM was 3903.1510−3m3/kg TSfed and 3338.310−3m3/kg TSfed for ANNs in the thermo-alkaline pretreated experiment. Gas chromatography show the CH4 and CO2 content of biogas generated to be 65.5±1.5%; 26±1% and 53±1%; 26±2% respectively. The co-digestion of peanut hull with poultry droppings and other energy-yielding substrates is further encouraged.