Abstract:
Abstract: The treatment and disposal technology of rural solid waste (RSW) through anaerobic digestion has become a hot research at home and abroad. However, the generation of foul odors, especially H2S, seriously affects the utilization rate of biogas and the service life of equipment, and causes environmental pollution during the anaerobic digestion process. This paper made an in-depth study on the anaerobic digestion of rural solid waste and the inhibition of H2S production. Completely stirred tank anaerobic reactors were used to carry out anaerobic digestion experiments on rural solid waste. The effects of different organic loading rate (OLR) on the degradation performance, gas production and stability of the anaerobic digestion system were studied, to find the optimum organic loading rate of anaerobic digestion of rural solid waste. At the same time, in order to reduce the H2S content of the malodorous gas produced by the anaerobic digestion process, the batch anaerobic digestion experiment with different proportions of solid waste and concentrated sludge (CS) was designed to observe the changes of H2S content in biogas. The results show that when the organic loading rate is 3 to 6 g/(L?d), the anaerobic digestion of the solid waste in the reactor can be stably operated, and the balance between the acid-producing phase and the methanogenic phase can be achieved. When the organic loading rate is 7 g/(L?d), the methane production rate is reduced to 325 mL/g and the volatiles solid degradation rate is 62.55%. At this time, the VFAS/TA is maintained between 0.4 and 0.8, and acidification may occur not very stable. Until the organic loading rate increased to 8 g/(L?d), the pH value decreased significantly, volatile fatty acid increased sharply, and the system started to run rancid and could not be operated stably. When the organic loading rate is 4 g/(L?d), the microbial degradation of the added solid waste is relatively sufficient, and the utilization rate of microorganisms is relatively high. Therefore, the increase of methane production is the most significant, the system is stable and the utilization rate of organic loading rate is higher when the organic loading rate is 4 g/(L?d). With the increase of the concentration of concentrated sludge, the content of H2S decreases obviously. When the concentration of VSRSW∶VSCS were 1:0.25, 1:0.5, 1:0.75, the degradation rate of H2S were 85.15% and 88.18%, 96.20%, respectively. The addition of sludge has a strong inhibitory effect on the production of H2S in the system, which has a significant effect on the utilization of biogas during the anaerobic digestion of domestic waste. Combined with the analysis of the composition of rural solid waste and concentrated sludge, the metal contents of the two materials are not obvious difference, but the humus content in the concentrated sludge was more than that of the rural solid waste, therefore, the humus content in the sludge may affect the production of H2S in the anaerobic digestion system.