Cow Dung Fermentation Production Of Bio-organic Fertilizer Process Optimization And Applied Research

With the rapid development of intensive livestock and poultry farms, the pollution of environment caused by the industry is getting more and more serious. Presently, aerobic fermentation is the main approach to make the livestock and poultry manure harmless and become useful resources, which could not only resolve the problem of pollution, but also plays a significant part in continuable development of agriculture. From the view of resource utilization, the isolation and mixture of strains as well as the optimization of technical conditions during the process of dairy manure fermentation were researched by the numbers, aiming at providing necessary parameters for sweeping treatments of manure and realizing the industrialization of bioorganic fertilizer. The results are as follows:1. In this paper, two strains of aerobic fungi with high cellulase activity were separated from yak manure. By identification, one is Trichoderma viride and the other is Aspergillus oryzae. Complex microbial community for the first fermentation was made by mixing the fungi and two strains of special bacteria (Bacillus subtilis and Pseudomonas sp.). The composting tests were carried out to look for a combination of microbial community with the highest activities, and the results indicated that the optimum ratio of the composition of compound microorganisms was Trichoderma viride: Aspergillus oryzae: Bacillus subtilis: Pseudomonas sp. = 2:2:1:1.2. The phosphate solubilizing microorganism, nitrogen fixation microorganism and potassium dissolving microorganism were screened by measuring their activities. Then they were mixed as 1:1 ratios to make complex microbial community for the second fermentation. The results proved that the activity of complex microbial community was more active than that of single strain due to the interaction between different strains.3. The primary technical parameters of the first fermentation were optimized. Based on single factor experiment, the optimum fermentation conditions were obtained through orthogonal experiments as follows: moisture content as 70%, C/N as 30:1, inoculation quantity as 3.5‰and turning frequency as one time every four days.4. The traditional second fermentation technics was ameliorated as follows: complex microbial community which contained phosphate solubilizing microorganism, nitrogen fixation microorganism and potassium dissolving microorganism, were added in the second fermentation with inoculation quantity of 1%. The results showed that the number of effective bacteria in bioorganic fertilizer amounted to 6.2×10~9(cfu)/g, outweighing that of national standard 2×10~8(cfu)/g.5. Medium-sized test in 50t scale were conducted to validate the optimized technical parameter achieved under the laboratory simulation conditions. The results revealed that materials could warm up fast and maintain for a long time at a high temperature, and that the bioorganic fertilizer had a high degree of maturity,a short fermentation cycle, as well as a low proportion of the residual moisture.6. Through 300t-scaled factory test, major technical parameters were finally determined as follows: in the first fermentation, moisture content as 70%, C/N as 30:1, inoculation quantity as 3.5‰and turning frequency as one time every four days, in the second fermentation, the complex microbial community which contained nitrogen fixation microorganism, phosphate solubilizing microorganism and potassium dissolving microorganism, were added with inoculation quantity of 1%. The first and second fermentation took each 15 days and 5 days. Consequently, all targets of bioorganic fertilizer were in line with national standard.