| In recent years, the method of organic solid waste using anaerobic fermentation has been widely studied. On the one hand, through anaerobic fermentation, much of organic waste can be greatly removed; on the other hand, the fermentation process will produce a large amount of biogas, the gas can be directly injected into the natural gas pipeline or as vehicle fuel after purification, alleviating increasingly nervous of fossil fuel. Therefore, whether it is from the treatment of organic waste perspective or from the perspective of development of renewable energy, the method of anaerobic fermentation has certain advantages.Nine kinds of biomass materials commonly used as the raw materials of anaerobic fermentation were used to investigate the effect of organic nutrient composition on the performance of continuous anaerobic fermentation process using wet single-phase continuous anaerobic fermentation. In the experimental process, first of all, the physicochemical properties and organic nutrient composition of the nine kinds of biomass materials were detected. Then, through a continuous anaerobic fermentation for 110 days, observed and recorded the changes of the operation process in the reactor, such as gas yield, pH, NH4+-N and feed material concentration et al. After the test, the test results were analyzed using the data processing software SPSS 19.0. In this experiment, main research results are as follows:(1)In the correlation analysis among the nutrition compositions, the result showed that the content of crude protein and crude fat do not exist significant correlation with other nutrition compositions; there was a significant negative correlation between the content of total sugar and the content of hemi-celluloses and lignin; there are significant positive correlation between the content of crude fiber and cellulose and lignin content, the result of regression analysis showed that, the content of crude fiber can be effectively identified 95.59% by the content of cellulose and lignin in the biomass.(2)In the detection of alkali degree of biogas effluent, a concept of methane bacteria alkalinity(MBA) was put forward for the first time. As to the traditional determination of alkalinity in the process, MBA was the alkalinity when pH decreased to 6.5(the lowest line methane bacteria tolerance pH). MBA could more reflect the ability of the material liquid pH can be stabilized above 6.5 than the traditional total alkalinity. According to the result of correlation analysis between biomass organic nutrition composition and MBA, MBA only had significantly positive correlation with the content of crude protein.(3)In the analysis of NH4+-N concentration of fermentation broth, a concept of TS ammonia production rate based of total solid(TS) was firstly proposed. TS ammonia production rate can be calculated through the actual test results, it can predict the biomass capacity of produce NH4+-N in the process of anaerobic fermentation. It has important practical significance to avoid ammonia inhibition. Among the nine kinds of materials, the ammonia production rate of chicken manure is the strongest, and the value reached 86.87mg/g-TS. The result of correlation analysis between the organic nutrition composition of biomass and TS ammonia production rate showed that the TS ammonia production rate was only significant positive correlation with the content of crude protein in the biomass.(4)In the investigation on the removal rate of VS, found that the VS removal rate was significantly correlated with the total sugar content in raw material. The variance test results of linear regression equation was significant, the coefficient of determination R2=0.7911, showed that the total sugar content in biomass can effectively determine the removal rate of 79.11%.(5)A concept of effective C/N(EFF C/N) was firstly posed in this paper, namely as the traditional calculation of C/N to, the carbon content of crude fiber or acid detergent fiber need to be substracted from the total organic carbon. The EFF C/N can truly reflect the optimal ratio of carbon to nitrogen for anaerobic fermentation, and provide better guidance for the mixed fermentation used two or more kinds of different materials. By comparing the test of nine kinds of material in all aspects of the continuous anaerobic fermentation, the reactors fed with cattle manure and pig manure proformed stability, the two effective carbon nitrogen ratios in the range of 10-16.(6)According to the concept of EFF C/N, leads to the concept of effective organic loading rate(E-OLR). As the calculation of the traditional organic loading rate, the quality of its molecular fraction of volatile solid need be substracted the quality of volatile solid of crude fiber oracid detergent fiber. Finally, under the assumption of equal effective organic load, the possibilities to cause a rancidity were compared amond the materials had EFF C/N of above 16. The comparison results showed that cassava residues > corn stalk ≈ corn > food waste > soybean straw, namely the higher EFF C/N, the more easily cause a rancidity. |
