High-solid thermophilic methane fermentation of food waste with an emphasis on Iron, Cobalt, Nickel requirements
The suitable requirements for iron, cobalt and nickel were examined in thermophilic methane fermentation of food waste. For this purpose, the effect of trace metals on the thermophilic methane fermentation of high-solid food waste was investigated using both batch and continuous experiments. The CSTR reactor was run with a working volume of 12L. The continuous experiment was comprised of three runs. During the first run, the HRT was stepwise decreased from 100 days to 30 days with an increase in the organic loading rate from 1.9 to 6.3 Kg-COD/m3.d. Stable methane fermentation was realized when the HRT was at both 100 days and 50 days. Four typical operation parameters : methane production rate, methane content, pH and total VFA concentration were stable in digester during both HRT 100 days and 50 days, indicating that the digester was start-up successfully. From the day 56 days (HRT 30days) a sudden drop in the gas production rate, pH and methane content was observed, corresponding with the accumulation of VFAs, which indicted that there maybe have some kind of inhibition caused the unstable in digestion. It was inferred that the inhibition factors may have been a lack of trace metals or a high ammonia concentration. The ammonia concentration, however, was not more than 1100mg/l, outside the ammonia inhibition range indicted by other researchers. As such, it was decided that the main reason for the gas inhibition must have been a lack of trace metals. According the results of the batch experiment, a combination of iron, cobalt, and nickle for 10, 1, lmg/1 respectively was added into the reactor once one and half months during the second run. Even though the gas production, methane content, and the pH had decreased, they were restored after adding the trace metals. During the third run, trace metals were added to the substrate to the effect that no inhibition was noted at all. Based on theoretical calculations and experimental results, it was found that the most suitable values for Fe/COD, Co/COD, Ni/COD are 276, 4.96 and 4.43 mg/Kg.COD, respectively, in the high-solid thermophilic methane fermentation of food waste.
fermentation high-solids mesophilic food waste
Hong Qiang YuYou-Li
College of Resources and Environment Northwest A&F University, Yangling 712100, China Graduate Schoo Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba,Aramaki, Aoba-ku, Senda
国际会议
天津
英文
109-119
2011-11-12（万方平台首次上网日期，不代表论文的发表时间）