Effect Of Total Solid Concentration On Anaerobic Fermentation Biogas Production At Different Temperature

Biogas technology can not only solve the rural energy shortage problem, but also dispose agriculture wastes, effectively solve the growing prominence of environmental issues and provide organic fertilizer. The quality of rural soil, water and air will be improved. To increase rural household biogas gas production, maximize the potential of raw material; in this study the fermentation process was simulated in laboratory, and researched the effect of total solid concentration on properties of biogas (include biogas production rate, cumulative gas production and biogas production efficiency of TS). The optimum total solid concentration and temperature of different raw material was obtained by SAS software, which can provide theoretical guidance for household biogas feeding rate, and realize the effective use of rural waste.A simulation experiment using self-designed constant-temperature anaerobic fermentation equipment was conducted in indoor conditions. Rural wastes (straw, corn stalks, chicken manure and cow dung) was used as digestion material, the substrate of constant temperature fermentation pool used as the inoculation substances. The temperature ranged from 20 to 40℃and TS increased from 4% to 20%. Exploring the relationship between biogas production and total solids concentration was explored and the optimum total solid concentration and temperature of different raw material would be determined. The main results are as follows:At the intermediate temperature, biogas was produced in different concentration using straw, manure and mixture of them as fermentation material. The maximum biogas production increased with the raise of temperature and TS. Biogas production rate of TS was different at different temperature, but showed the similar change, which took on wave-like drop after reaching the biogas production peak, and 2～3 peak was found during the fermentation process.(1) Straw was used as fermentation material. The result showed that the maximum cumulative biogas production of wheat straw was observed at 16% and 40℃, 20% and 30℃for corn wheat. The maximum biogas production rate of wheat straw was found at 25.0℃and 15.6%, and for corn straw, biogas production rate at 16.9% increased with the rising of temperature ranging from 20 to 40℃.(2) Straw was used as fermentation material. The result showed that the maximum cumulative biogas production of chicken manure and cow dung was observed at 20%, 40℃. The maximum biogas production rate of chicken manure was found at 34.9℃, 7.3%, and for cow dung, it increased with the rising of temperature ranging from 20 to 40℃at 9.2%.(3) The mixture of straw and manure was used as fermentation material. The result showed that the maximum cumulative biogas production of chicken manure and wheat straw mixture was found at 16%, 40℃, 20%, 25℃for chicken manure and corn straw mixture, and 20%, 30℃for cow dung and wheat straw mixture as well as cow dung and corn straw mixture. The maximum biogas production rate of chicken manure and wheat straw mixture was observed at 11.8%, 36.4℃, and 14.6%, 32.8℃for chicken manure and corn straw mixture, 10.5%, 39.8℃. The maximum biogas production rate for cow dung and wheat straw mixture, the maximum biogas production rate increased with the rising of temperature at 8.9% when temperature was above 30℃(4) The optimum TS for biogas production was affected significantly by the characteristic of fermentation material such as C/N, cellulose content. Therefore, feeding rate should be adjusted based on material to obtain the optimum biogas production.