Pilot Study on Anaerobic Digestion of Lake Sediment

Anaerobic digestion of lake sediment were investigated by using four factors and three levels orthogonal experimental design method. The results showed that the influences of different parameters on the anaerobic digestion in descending order were digestion temperature (T), raw material carbon-nitrogen ratio (C/N), total solid concentration(TS) and inoculum-substrate ratio(ISR). The former two had obvious impact on the anaerobic digestion and the latter two hadn't. Optimum process conditions were T 55 degrees C, C/N 20: 1, TS 10%, and ISR 1. T 55 degrees C, C/N 20: 1 and ISR 0.5 were suggested to actual dreged sediment, dosing ratio should be determined from follow-up experiment. If dreging depth of Nanhu is 40cm, 35 millions m(3) biogas and 44.85 million Kw.h net electric generation in which power consumption of anaerobic digestion setup had been deducted can be got. If all polluted lake were dredged and the dredging depth is 20cm, then 70 billions m3 biogas and 90 billion Kw.h net electric generation can be got. After digestion the nutrient was still rich in sediment and heavy metal content could meet the standard of landuse of sludge, therefore the sediment can be landuse.