Method for producing mash gas from municipal sludge through dry method anaerobic fermentation

Abstract

The invention relates to a method for producing mash gas from municipal sludge through dry method anaerobic fermentation, which belongs to the field of solid waste reclamation, and can overcome the difficulties difficult mass transfer, difficult gas overflow and the like caused by dewatered sludge which has high viscosity, no fluidity, no gaps and the like. The method comprises the following steps of: performing biological pre-drying on the dewatered sludge, and stacking the dewatered sludge in an aerobic environment for 2 to 3 days; adding the material after the biological pre-drying into anaerobic granular sludge or biogas residues to perform inoculation, and performing static starting for 6 to 8 days; performing acidogenic fermentation on the material under an aerobic or anaerobic condition, performing spiral band type or anchor type stirring, and adjusting the pH if necessary; performing methanogenesis fermentation on the material after acid production under an anaerobic condition, performing extruding type stirring, keeping the temperature of the material to be 35+ / -1 DEG C, and keeping the pH between 6.6 and 7.5; and performing refluxing inoculation on part of the biogas residues, and performing aerobic compost stabilization on the rest of the biogas residues. The method can be used for beneficial utilization of the municipal sludge and the recovery of biomass energy sources, and compared with wet fermentation, the method can save equipment investment and land occupation.

Description

technical field [0001] The invention belongs to the field of solid waste recycling, and in particular relates to a method for producing biogas by dry anaerobic fermentation of urban sludge. Background technique [0002] The amount of dewatered sludge produced by urban sewage treatment plants due to the purification of domestic sewage is huge. At present, the annual collection capacity is about 26 million tons. The treatment and disposal of sludge in sewage treatment plants mostly use concentration and dehydration followed by landfill. This method not only occupies limited land resources, but also easily causes secondary pollution. In addition, the resource utilization rate of landfill is low, which does not conform to the principle of sustainable development in my country. In recent years, the global energy structure is undergoing a transition from fossil energy-based to the coexistence of multiple energy sources, and issues such as food security and environmental degradati...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the difficulty of mass transfer due to the characteristics of high viscosity, no fluidity, and no porosity in the process of urban sludge dry fermentation, as well as difficulties such as difficult gas overflow, and provide a kind of urban sludge dry anaerobic fermentation process. Method for producing biogas by fermentation