Characteristics Of Methane Production By Coupling Aerobic And Anaerobic Fermentation Of Chinese Herb-extraction Residues

The Chinese Herb-extraction Residues is a kind of important organic waste with a annual output above 1000000 tons in china. The rapid development of Chinese herbal medicine industry contributed to the economic development and urbanization construction of our country, at the same time, the CHER what produced in Chinese herbal medicine production process brought pressure to the ecological environment was cannot be ignored. CHER was rich in carbohydrates, glycosides, anthrone, lignin, alkaloids and crude protein of organic compounds, it can cause a serious blow to the surrounding ecological environment if processing is undeserved. At present for the treatment of CHER is common sanitary landfill and incineration, however, these methods of disposal cause secondary pollution of the underground water, the surrounding soil and air. At the same time, CHER is a kind of biomass resources what can be degraded by anaerobic microorganisms for fermentation, but CHER contains about 50% neutral detergent fiber, owing to the physical shielding effect from lignin, hinder microbial cell extracellular enzyme contact cellulose and semi-cellulose, limit hydrolysis rate of cellulose and semicellulose, resulting in the anaerobic fermentation process is slow, VS methane production rate is low. Obviously, degradation of lignin is the primary step of hydrolysis acidification. Lignin initial cleavage required the presence of molecular oxygen, without aerobic treatment lignin hardly degraded by microbes in anaerobic environment. Therefore, conducted anaerobic fermentation of CHER into two phase, that was per mesophilic aerobic hydrolysis fermentation before the methanogenic fermentation, and comparison Single phase anaerobic methane fermentation process and aerobic and anaerobic twophase coupled methanogenic fermentation process of different types of CHER, the process parameters such as accumulative methane production, VS methane yield, and the degradation rate of TS were studied in depth. The results showed that:(1) Anaerobic aerobic coupling of two-phase fermentation model has significant effect on improve methane potential, increase the cumulative methane production and VS methane yield of anaerobic fermentation. The maximum growth rate of cumulative methane production was 35.7%, the maximum growth rate of VS methane yield was 31.1%, the maximum growth rate of methane daily yield was 52.4%.(2) Aerobic hydrolysis and acidification microbe can destroy physical shielding of lignin effective, causing microorganisms can directly attack the cellulose and semi-celluloses, to improve the degradation rate of TS.(3) Different aerobic hydrolysis fermentation time on two CHERS anaerobic methanogenic fermentation of various indexes of lifting has a significant difference. In the experiment on two kinds of CHERS are aerobic hydrolysis for 24 h. The cumulative methane production, VS methane yield and the maximum amount of methane daily yield of CHER-A has improved 30.9%, 23.6% and 25.5%, respectively. Substrate degradation rate of TS in the ascent raised to 37.9%. The cumulative methane production, VS methane yield and the maximum amount of methane daily yield of CHER-B has improved 35.7%, 31.1% and 52.4%, respectively. Substrate degradation rate of TS in the ascent raised to 40.0%. In summary, the optimal operating cycle of the aerobic hydrolysis phase is 24 hours in anaerobic aerobic coupling of two-phase fermentation model.