Process for improving methane yield of anaerobic digestion of excess sludge through pretreatment of papermaking white mud

Abstract

The invention relates to a process for improving the methane yield of anaerobic digestion of excess sludge through pretreatment of papermaking white mud. The process comprises the following steps: S1, concentrating the excess sludge to obtain concentrated sludge with reduced water content; S2, mixing the concentrated sludge and the papermaking white mud in an alkaline hydrolysis tank, adjusting a first dosing pump and a second dosing pump, controlling the pH value in the alkaline hydrolysis tank to be 11+ / -0.5, stirring and staying for 60 min, and thus obtaining alkalized sludge; S3, carrying out hydrolysis fermentation on the alkalized sludge obtained in the step S2 in a low-temperature hydrolysis tank at the temperature of 60+ / -1 DEG C to obtain pretreated sludge; and S4, reducing the temperature of the pretreated sludge to 35 DEG C through a muddy water heat exchanger, mixing the pretreated sludge with cooked sludge subjected to anaerobic digestion, and feeding the mixture into an anaerobic digester through a screw pump for anaerobic fermentation to generate biogas. According to the invention, resource utilization of the papermaking white mud which is a dangerous solid waste is realized, and a new treatment method is provided for treatment of the papermaking white mud.

Description

technical field [0001] The invention belongs to the technical field of sludge pretreatment equipment or devices, and in particular relates to a process for improving the anaerobic digestion methane yield of excess sludge through pretreatment of papermaking white mud. Background technique [0002] Excess sludge is the product of biochemical treatment in urban sewage treatment plants, and its output is about 0.3% to 0.5% of the treated water. In 2013, my country's sludge (water content 80%) output exceeded 40 million tons. According to the planned sewage treatment capacity in 2020, the sludge output will reach 60-90 million tons by 2020. The secondary pollution problem is that the sludge output is rapid The obvious results brought about by the growth. In addition, due to the cost of sludge treatment, the cost of sludge treatment can account for about 30%-50% of the operating cost. In developed countries, the cost of sludge treatment can even reach half of the total investment o...

AI Technical Summary

Problems solved by technology

In 2013, my country's sludge (water content 80%) output exceeded 40 million tons. According to the planned sewage treatment capacity in 2020, the sludge output will reach 60-90 million tons by 2020. The secondary pollution problem is that the sludge output is rapid The obvious results brought about by the growth. In addition, due to the cost of sludge treatment, the cost of sludge treatment can account for about 30%-50% of the operating cost. In developed countries, the cost of sludge treatment can even reach half of the total investment of sewage plants. Above, the problem of sludge disposal has become a major burden for the normal operation of sewage plants

However, the traditional anaerobic digestion of sludge has the disadvantages of slow degradation rate and long reaction cycle.

Images