Effect of Temperature Fluctuation on Performance of Thermophilic Anaerobic Digestion for Treating Organic Fractions of Municipal Solid Waste
温度波动对城市有机生活垃圾高温厌氧消化工艺影响

The laboratory-scale daily fed experiment study was carried out to assess the effect of temperature fluctuation on performance of the thermophilic reactors for organic fraction of municipal solid waste (OFMSW). The temperature of the reactor was lowered from 55 degrees C to 20 degrees C in case of heating failure and the duration in the low temperature were 1, 5, 12 and 24h respectively. The time of downward and upward temperature were within 2h. The organic loading rate was 8.0 g (L x d)(-1) in the steady-state and retention time was 15 d. The results show that the biogas production almost stop and total VFA, VFA such as acetate and propionate are rapidly accumulated when the temperature fluctuated, accompanied by the fall in pH. But the pH values would be in the normal range for the high buffering capacity in the digesters. The delay time of methane production restored was 3, 11, 56 and 72h respectively. It showed the longer the duration in low temperature, the more the decay of methanogenic archaea. Temperature fall not only affected the methanogensis but also the hydrolysis and acidification. Thermophilic microorganisms appeared to be highly resilient during temperature fluctuated process.