Study On Biochar Promoting Anaerobic Digestion Of Gas Production From Kitchen Waste

Biochar has large surface area,good adsorption performance and high stability,which all provide the possibility for biochar as an additive to promote the stability of anaerobic digestion process and increase biogas production.In this paper,four types of biochar were prepared at the same temperature.The influences of different biochars on the anaerobic digestion process of simulated wastewater and kitchen waste were studied.The biochar with the best promotion effect was selected,and the influence of biochar addition,initial pH and sludge inoculation rate on gas production of kitchen waste was discussed.Conclusions are as follows:?1?Four types of biochar were prepared from pine sawdust,bamboo,coconut shell and bagasse at the same temperature,and their basic physical and chemical properties and structural characteristics were analyzed.The results showed that the yield and ash content of coconut shell biochar in the four kinds of biochar were the highest,the yield of bagasse biochar and the content of ash was the lowest,the pH value was all alkaline,the alkalinity of bagasse biochar was the worst,and the content of?-OH?functional group on coconut shell biochar is the highest.The largest specific surface area is coconut shell biochar,and the smallest is bagasse biochar.?2?Four types of biochar were added to simulated wastewater for anaerobic digestion experiments to explore the effects of four types of biochar on anaerobic digestion of simulated wastewater.The results showed that all four kinds of biochar can reduce the acidification process of wastewater,reduce the stagnation period,increase the degradation of organic matter,increase the activity of methanogens,and increase the production of biogas.However,there is no significant impact on the change of NH₄⁺-N.The worst adjustment group is bagasse biochar B_G,the best degradation is group coconut shell biochar B_Y,the largest gas production group is wooden biochar B_M,and the highest methane content group is bamboo biochar B_Z.?3?Four types of biochar were added to the kitchen waste for anaerobic digestion experiments to study the effects of four types of biochar on anaerobic digestion of food waste.The results showed that all four kinds of biochar can alleviate the acidification process of anaerobic digestion of kitchen waste,reduce the stagnation period,increase the degradation of organic matter,increase the activity of methanogens,increase the biogas production,and have a certain impact on the changes of NH₄⁺-N.Among them,the poorest adjustment group is bagasse biochar C_G,and the best degradation group is coconut shell biochar C_Y;the largest gas production group is coconut shell biochar C_Y,and the highest methane content group is coconut shell biochar C_Y.?4?To investigate the effect of coconut shell biochar addition,initial pH and sludge inoculation rate on gas production from kitchen waste.The results showed that when the inoculum amount of sludge is 20.98%,the initial pH is 7.05,and the biochar is added at22.14g/L,the anaerobic digestion of kitchen wastes have the best gas yield with a methane yield of 331.66 L/Kg TS.