Experimental Study Of Anaerobic Co-Digestion With Cow-Dung And Food Garbage

With the increase in population and the improvement of people’s living standards, kitchen waste and livestock manure emissions increasing, at the same time since the1990s, a large number of experimental studies have been carried out on the kitchen waste anaerobic fermentation technology by researchers at home and abroad. This will have a far-reaching social significance and economic benefits in Waste reduction, harmless and resources.Based on this, in this article based on the study of anaerobic digestion processing technology at home and abroad on the kitchen waste.The homemade CSTR reaction tank as anaerobic reactor and using semi-continuous type packing way to feed, Cow dung and kitchen waste by VS1:1for feeding, organic load VS from0.50gVS/(L·d) gradually increasing to2.75gVS/(L·d), maximum tolerable organic load of gradual increase in cow dung and kitchen waste was been studied.Each organic loading phase of stable running for two weeks and the trial lasted140days. pH, volatile fatty acids (VFA), alkalinity, ammonia, gas production and methane production volume is used as an indicator,under the condition of the medium temperature makes the study of the cow dung mixed with kitchen waste anaerobic digestion(named R1). The experimental results were compared with "anaerobic co-digestion of kitchen waste with pig manure as inoculum"(named R2)in hydrolysis acidification, gas production, methane yield, alkalinity and ammonia. The results of this experimental and compared show that:1. In the study of anaerobic co-digestion with cow-dung and food garbage,the entire process of anaerobic digestion, the pH value range of the reactor maintained at6.79-7.19; VFA concentration remains from72to360mg/L; the total alkalinity of digestion reaction system is from8075tol5366mg/L; ammonia nitrogen concentration has between1986and2047mg/L.2. In the study of anaerobic co-digestion with cow-dung and food garbage,gas production increases steadily, but the system was not easy to obtain a stable gas production when the concentration of organic load higher than2.50gVS/(L·d) and2.50gVS/(L·d) for the best gas organic loading. Methane-producing rate is relatively stable, from52.3%to59.5%.when experiments in the feed in the process of organic load concentration is0.50-2.75gVS/(L·d),anaerobic digestion system is able to run steadily.3. The overall average of VFA R1, R2, is respectively175.6mg/L and189.1mg/L, illustrating the hydrolysis effect of no significant difference, but the VFA of R1was more stable.4. With the same organic load,the gas production of R2was higher than R1’s.Both the methane production rate and stability of R1are higher than R2’s.5. The alkalinity difference of R1rector and R2rector is not big and R2is more stable. The ammonia values of R1and R2have been relatively stable, and R1ammonia level is higher than R2, R1ammonia is more stable.