Study On Characteristics Of Mixed Fermentation Of Cow Dung As Multiple Materials

With the improvement of living standards,rural and agricultural waste discharge of rural residents living garbage is constantly increasing.A large amount of rural waste improper handling not only caused a large number of biomass energy waste to the countryside environment caused great destruction,but also for the rural environment caused great damage.Anaerobic fermentation technology can effectively handle the scattered rural waste.Rural waste produced mainly livestock excrement and urine,eat hutch garbage and sewage.Based on the above three kinds of wastes as raw materials for the anaerobic fermentation of three kinds of material mixed fermentation technology was studied.First study pure cow dung in different temperature,different concentration of fermentation under the condition of nature,then the mixed fermentation parameters of cow dung and eat hutch garbage,cow dung and sewage mixed fermentation process parameters of experimental research,finally through the orthogonal experiment method to obtain cow dung,eat hutch garbage and sewage mixed fermentation,the optimal process parameters.The experimental results showed that:(1)The liquid of cow dung separation fermentation process started relatively quickly,the daily gas production is relatively stable,compared with pure cow dung group daily gas production is low,total gas production of short duration,the highest cumulative TS methane production 242ml/g,the cumulative vs methanogenic 282ml/g,were higher than pure cow dung group.The anaerobic fermentation of pure cow dung started slowly.Generally,there are two obvious peak of gas production and fermentation liquid concentration is low,fermentation to start sooner,the gas generation peaks sooner.TS=4% group accumulated TS methane production highest 223ml/g,TS=6% cumulative TS methanogenic quantity highest 184ml/g,TS=8% cumulative TS methanogenic quantity highest 204ml/g;group TS=4% cumulative vs methanogenic quantity highest 260ml/g,TS=6% cumulative vs methanogenic quantity highest 216ml/g,TS=8% cumulative vs methanogenic amount is the highest in the 238ml/g.There is a matching relationship between fermentation of dairy manure fermentation temperature and feed concentration and low concentration of material at room temperature using fermentation can achieve ideal effect,and high concentrations of material used in mesophilic or thermophilic fermentation to make methane conversion rate higher,cow dung liquid separation because of the TS concentration is too low,suitable for room temperature or high temperature fermentation.Under different conditions of dairy manure fermentation test of actual production of methane potential highest is in TS=4%,mesophilic fermentation,methane production potential for 260 mL/ g VS,reached 48% of the theoretical potential gas production.(2)Cow dung anaerobic fermentation process,fermentation broth of TS and specific heat volume with significant correlation,the correlation between TS and density in general,poor correlation between the density and specific heat capacity,decided to dairy manure fermentation liquid than the heat capacity of the main factors is the water content of the fermentation broth.(3)Food waste and cattle manure with appropriate ratio of mixed fermentation can effectively avoid excessive acidification of food waste.Compared with food waste and cattle manure mixed fermentation and fermentation can improve the gas production of single cow dung.Under the same experimental conditions during the fermentation temperature of pure cow dung to 35? VS the highest methane yield is 260ml/g and mixed fermentation of vs methane content is the highest in group 2(cow manure and kitchen waste ratio of 3:1,TS is 6%,the coverage rate of 20% to 293ml/g.In the proportion of food waste and cattle manure in between 1:3~1:7,restaurant kitchen garbage proportion bigger,unit of TS cumulative methane production amount is large,gas production potential of restaurant kitchen garbage than cattle manure biogas potential.Various factors of restaurant kitchen garbage and cow dung mixed fermentation gas production characteristics of from big to small is as follows: TS of fermentation liquid,ratio of raw materials,vaccination rates.The best combination of gas production is obtained by orthogonal experiments with cattle manure and kitchen waste ratio of 3:1,TS is 8%,the vaccination rate was 20%.(4)Cow dung and sewage mixed fermentation but the realization of cow dung TS from high and low life sewage of high moisture content were complementary,cow dung and sewage mixed in different proportions of three groups of testing cumulative production volume are 12505 mL,13203 mL and 18395 mL,unit mass vs gas production rate is 208 mL/g,182 mL/g and 178ml/g.(5)Of cow dung,food waste and sewage mixed fermentation process,cow dung,food waste and sewage quality than 3:1:20 unit group VS production gas rate is the highest,reaching 251 mL/g;cow dung,kitchen garbage and sewage quality ratio of 3:1:12 cumulative production volume reached the highest 22017 mL.