Experimental Study On The Technologies Of Anaerobic Digesiton For Treating Manure From Chicken Farms

The manure from large-scale chicken farms, which was in high nitrogen content, wasnot easy to be treated by anaerobic digestion. The emissions and concentration of manureand wastewater for disposal was varied in chicken farms since the way of clearing farmmanure was different, so the selection of the anaerobic technology and parameter of post-treatment process were also not the same. Based on the investigation of chicken farms inSichuan this study focused on the some technical problems in anaerobic digestion of themanure for providing experimental data to support anaerobic digestion of chicken manure:1) Experimental study on operational parameter of aerobic post-treatment after anaerobicdigested low concentration manure,2) Experimental study on the performance of dry anaerobic digestion with batch test for high-solid chicken manure. The conclusions of wholepaper were as follow:（1） The data of experiment showed that poultry manure&sewage could be treated by anaerobicdigestion with renewable energy benefit. For meeting the requirements both for maximum biogasproduction in the anaerobic digestion period and digested effluent feasible treated in post aerobic-treatment period, the HRT of anaerobic digestion should be less than6days, while theBOD5/COD and C/N index of effluent could just suit the requirement of post-treatment. It wasshowed by making a comparison between our data with poultry manure and others with pig andcaw manure that the longer the HRT of anaerobic digestion, the worse of the result of aerobicpost-treatment. For farm wastewater with high nitrogen content, the HRT of anaerobic digestionas pre-treatment period should be comparably less.（2） Addition of straw was demonstrated an effective method to improve dry anaerobic digestion ofchicken manure and the straw needed to achieve a certain level. When the addition ratio of strawwas from14%to35%, the biogas yield increased with the ratio, the total biogas yield of fourtreatments in sixty days was32227ml、62817.5ml、67282.5ml、76785ml, respectively, meanwhile,methane content of biogas was all up to60%. The maximum volume gas productivity of35%addition was1.78L （L d）^-1.（3） Pig manure was the best performance of biogas yield in comparison of chicken manure andcow manure with14%straw addition in batch dry anaerobic digestion test, and even superior tothe chicken manure with35%straw addition. The methane content of all treatments of chickenmanure was not increased as fast as pig manure and cow manure, however, at the late thirty days,the methane content of chicken manure was all above70%, that was higher than pig manure andcow manure.