Impact Of Aerobic Pretreatment On Anaerobic Digestion Of Bioorganic Municipal Waste (BMW)

The effect of an aerobic pre-treatment of bioorganic municipal waste (BMW) on anaerobic digestion performance and biogas production is paied attention to by people, because during an aerobic pretreatment pathogens can be reduced and fast degradable bioorganic substances will be reduced, which lowers the potential for a low pH value through acidification. The effect of an aerobic pre-treatment of on biogas production is researched by anaerobic batch experiments at mesophlic(37℃) condition and anaerobic continuing experiments at mesophlic(37℃) and thermophilic (55℃) condition, applying the small anaerobic digestion setting and continuously operated completely stirred tank reactor (CSTR) respectively, the material is the BMW after source separation. The results show:The organic fraction in Chinese MSW amounts to about 74% (m/m) and the organic fraction in the BMW is about 87.9% (m/m). The non-bioorganic fraction amounts to about 68.4% (m/m) in the RMW collected after source separation by the citizens in the pilot area.In the batch mesophilic anaerobic digestion, the cumulated total biogas yield, the average bio-methane content (v/v), the total VOC degradation of the aerobic pretreated BMW material is in total lower than that from the un-pretreated material, but the specific biogas- production rate of pretreated material during the first 20 days is higher than that of the un-pretreated material. At the beginning of the anaerobic digestion, the pH value of the aerobically pretreated material is higher, respectively more beneficial for biogas-production, than the pH value of the un-pretreated material.In the continuing mesophilic anaerobic digestion, at a HRT of 22d, when the maximum specific gas production was achieved, the untreated material was producing 4.1 L/L·d-1 and the pretreated material 3.6 L/L·d-1. But at a HRT of 18.4d the biogas production of aerobic pretreated material is with 2.61 L/L·d-1 (OLR=11.61gVS/L·d-1) higher than the biogas production of 1.87 L/L·d-1 of the un-pretreated material with an organic loading rate of 12.98gVS/L·d-1. Under thermophilic anaerobic digestion conditions and at retention times higher than 42 days, the biogas production of the aerobic pretreated material is higher than that from un-pretreated material.