Advanced dry anaerobic digestion method based on sludge modification pretreatment

Abstract

The invention relates to an advanced dry anaerobic digestion method based on sludge modification pretreatment. The method comprises the following steps: pre-treating dehydrated sludge for 10-60 minutes at a certain temperature and pressure, and cooling to a certain temperature value at the fermentation temperature of 35-42 DEG C or 50-60 DEG C so as to obtain modified sludge; fully mixing the modified sludge with inoculated sludge at a volume ratio of (1:10)-(1:1), putting the mixed sludge in an anaerobic fermentation tank, and starting a temperature control device so that the material temperature is controlled at the fermentation temperature to stand for 3-10 days; then carrying out continuous feed and discharge, controlling feed and discharge amount each day so as to gradually improve operation load, carrying out feed by using the modified sludge with the feed amount of 0.5-1m<3> / d, maintaining the operation for 12-30 days under the load level when the load is improved once, improving the load again after a digestion parameter discharge VS and daily gas production amount are stable until a planned load is reached; after starting the anaerobic digestion process, performing a stable operation stage; carrying out continuous feed and discharge, and controlling material retention period to 12-20 days so that the digestion load is maintained at a set level; and treating biogas residue. By using the method, the viscosity of the sludge can be reduced, dry digestion speed and gas production amount are improved; and compared with the wet fermentation, equipment investment and occupied soil are saved.

Description

technical field [0001] The invention belongs to the field of solid waste recycling, and in particular relates to an advanced dry anaerobic digestion method based on sludge modification pretreatment. 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 ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the problems of slow hydrolysis and acidification process, insufficient methanogenic substrate, and slow fermentation process due to the large amount of refractory substances and microbial residues in the material in the dry digestion process of municipal sludge. Advanced dry anaerobic digestion method for sludge modification pretreatment