The experimental study of biogas production when digesting chicken manure with a biochar additive

Abstract

The research aims to evaluate the output of biogas and the concentration of CH4 and gaseous impurities such as CO2 and H2S in the process of digesting chicken manure without additives (experiment A) and with 10% of biochar additive (by mass of the dry load) (experiment B) under anaerobic and mesophilic conditions. It has been found that the average output of biogas from a particular amount of chicken manure (experiments A and B) obtained in the 45-day experimental research is similar in both cases and reaches 12.88 l d–1 and 12.36 l d–1, respectively. However, the biochar additive increases CH4 concentration in biogas and reduces the concentration of gaseous impurities (CO2 and H2S) in biogas. The maximum concentration of CH4 in biogas obtained from a load of manure with biochar additive is higher than that in biogas obtained by using a load without a biochar additive, and reaches 72.0% and 68.5%, respectively. The average CO2 concentration, reaching 33.09% and 47.5%, respectively, in biogas obtained from the load with 10% of biochar additive is lower than that in biogas obtained from the manure load without an additive. The average concentration of H2S in the biogas obtained in experiment B is lower than that in experiment A and reaches 95.9 mg m–3 and 195.5 mg m–3, respectively. The biochar additive adsorbs gaseous impurities (CO2 and H2S) from biogas without adsorbing CH4.