Study Of Anaerobic Fermentation Of Dairy Cattle Manure In Normal Temperature

The temperature of anaerobic fermentation is 35 ℃ mostly, but the air temperature of winter is low in the northern province, Hei Longjiang, so the expansion of anaerobic technique has been restricted tremendously in north. Hitherto, the scale of firedamp production is still placed in the mode of family. The biogas is produced slowly and the result of fermentation is bad. For developing the anaerobic technology quickly in Hei Longjiang province, the experiment of anaerobic fermentation was carried out at 20-30℃ with dairy manure under the condition of laboratory. The influence regulation of each factor to every guideline was analyzed in experimental process and the variety regulation of anaerobic fermentation was investigated in normal temperature in order to provide useful data for the further research of aftertime. The major contents and results included the following four aspects:(1) The three elements of influencing COD removal, the total production of biogas and the ratio of producing biogas were liquid density, temperature and the quantity of microbe. The range were 4~6%,20~30℃,0~40%. Using the orthogonal experiments of rotation assemblage of two times, the effect equations, curves, the optimum and so on. were gotten, and the results were tested, The results suggested that three factors had alternating effects each other; different temperature corresponded to different liquid density and the quantity of microbe; 20℃ corresponded to low quantity of microbe, and 30℃ corresponded to more quantity. The production of biogas was not increased with the raise of temperature, the results of fermentation prefered 20℃ to 25 ℃; and the result of 30℃ was optimal. Three elements of the best COD removal, total production of biogas and the ratio of producing biogas were (7%, 30℃,40%.), (11%, 30℃, 40%), (6%,30℃,40%) .(2) In experimental process, through the survey of VFA and PH, the situation of anaerobic fermentation was monitored. The mechanism of anaerobic fermentation and the regulations of variety were studied. The results showed that the change of VFA and PH was connected with each element tightly.(3) The experimental results of 30℃ and 35℃ were compared in condition of the same liquid density and the quantity of microbe. The liquid density and the quantity of microbe were 6% and 40%. The results showed that the production of biogas at 30 ℃ was high, but its COD removal was low.(4) Under the condition of the same temperature and the quantity of microbe, the experimental results of different liquid density were compared. The experimental material was themixture of.excrment and urine. The liqid density was 2%, 4% 6% and 8% respectively. This experiment studied that the fermentative mechanism of the mixture of manure and urine. The experimental results showed that the ammonia had a good ability of buffer and prevented a quantity of acid in the container of fermentation. The best liquid density was 6%, which was as the optimal results of the ratio of producing biogas.