A method for strengthening anaerobic dry fermentation of dewatered sludge to produce methane

Abstract

The invention provides a method for strengthening the anaerobic dry fermentation of dewatered sludge to produce methane. The method comprises the following steps: 1) placing the dewatered sludge in a steam explosion kettle, and adding 1-5% of the weight of the dewatered sludge Calcium oxide and stirred evenly, maintained at a temperature of 180-200 °C and a pressure of 1-1.5 MPa for 10-30 minutes, and then released the pressure instantaneously to collect the result; 2) Inoculate the result of step 1), the inoculum was The dewatered sludge that has not been treated in step 1) is subjected to acidogenic fermentation under facultative conditions; 3) adding dry fermentation inoculum and a nutrient solution composed of phosphate and trace elements to the result of step 2), stirring evenly , for anaerobic dry fermentation. The invention can greatly improve the biodegradability of the sludge and greatly increase the methane gas production, the process is simple, no pollution, and has very huge application prospects.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for strengthening anaerobic dry fermentation of dewatered sludge to produce methane. Background technique [0002] With the growth of population, the consumption of urban domestic water is gradually increasing, and the pressure of domestic sewage treatment is also increasing. The activated sludge method is the most efficient and efficient treatment method for sewage treatment plants, but a large amount of municipal sludge will be produced in the process. In order to facilitate post-treatment such as transportation and landfill, these sludges are dehydrated into dewatered sludge with a high solid content. As early as 2007, China's dewatered sludge production reached 4.54×10 6 tons, and this figure is growing at a rate of about 10% per year. Dewatered sludge not only contains a variety of bacterial cells, organic debris and other organic matter...

AI Technical Summary

Problems solved by technology

[0005] Although anaerobic digestion technology has the advantages of reduction, harmlessness, energy recovery and resource recycling for the treatment of municipal sludge, there are still some deficiencies in the treatment of municipal sludge in the prior art: 1. For organic components The utilization rate is not high; 2. It needs a long reaction time; 3. It can only bear a low organic load rate

[0009] However, some problems may arise during the anaerobic digestion process of anaerobic dry fermentation: 1. The pH value of the anaerobic digestion system is lowered due to the rapid acid production stage at the start-up stage, which exceeds the tolerance range of the anaerobic methanogenic bacteria and causes the system to collapse; 2. The tolerable ammonia nitrogen concentration is low, generally only 2500mg / L, such as (Feng Lei, Li Rundong. Journal of Agricultural and Environmental Sciences, 2011, 30(11): 2374-2378), the ammonia nitrogen concentration in the middle and late stages of anaerobic digestion If it is too high, the biological function of the anaerobic methanogenic flora of the system will be inhibited, and the amount of methane produced will decrease

The anaerobic dry fermentation technology of dewatered sludge has not yet been practically applied due to the high difficulty of system operation, difficulty in controlling the anaerobic process, and insufficient research.

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