Method for increasing yield of short chain fatty acid produced with excess sludge through enzyme and alkali combined pretreatment

Abstract

The invention belongs to the technical field of environment protection, and relates to a method for increasing the yield of short chain fatty acid produced with excess sludge through enzyme and alkali combined pretreatment. Precipitated concentrated sludge is obtained after excess sludge stands at 4 DEG Cfor 24 h, proteinase k is added into the concentrated sludge till the concentration of proteinase k ranges from 0.018 U / gVSS to 0.022U / gVSS, the concentrated sludge is hydrolyzed for 22 h to 26 h under 35 DEG Cto 37 DEG Cwith the stirring speed of 120 rpm, then, 10% of anaerobic granular sludge is inoculated, the pH of the sludge is adjusted to range from 9.5 to 10.5, fermentation is carried out for 4 days to 6 days in a reactor under 35 DEG Cto 37 DEG Cat the stirring speed of 120 rpm, short chain fatty acid mixed liquid which mainly contains acetic acid, propionic acid and butyric acid is obtained, and the mixed liquid can serve as a chemical material with high additive value and a methanogenesis matrix. The hydrolysis rate of sludge is increased because the proteinase k is added; the generation of short chain fatty acid is inhibited due to the alkaline condition, but because more than two pretreatment manners are combined, strict anaerobe, particularly clostridium, in acid production microorganisms is enriched, the proportion of facultative microorganisms is reduced, and the acid production rate and the acid production quantity of substrate are increased.

Description

technical field

[0001] The invention belongs to the technical field of environmental protection, and relates to a method for improving the production of short-chain fatty acids in excess sludge through combined enzyme-alkaline pretreatment. Background technique

[0002] As of 2013, there were more than 3,500 sewage treatment plants above the county level in my country, accompanied by a large amount of surplus sludge, and the total sludge production in the country reached 30 million tons (calculated with a moisture content of 80%). It is estimated that by 2020, the sewage Mud output will exceed 60 million tons. Because sludge contains a large amount of organic matter, the energy and resource utilization of sludge has been widely valued by researchers. Due to the social needs of sustainable development and the government's policy support, the focus of solid waste treatment has shifted from pollution control to resource utilization. With the engineering application of anaerobi...