Method for deactivating pathogen in mud of city waste water factory

Abstract

The method of deactivating pathogen in mud of city waste water treating yard belongs to the field of mud resource utilizing technology. Material refluxing method is adopted to realize the circulation of dominant fermentation colony, marketable VT bacteria is used as inducing bacteria in initial fermentation, and the ratio between the thrown amendment and refluxed material is regulated based on the property of mud. In the dynamic aerobic fermentation reactor, dynamic aerobic fermentation is performed for about 10 days to deactivate pathogen under certain ventilation and stirring conditions. The method can raise the temperature of the material to over 55 deg.c and maintain the temperature for over one week without needing outer heat source in deactivating pathogen. The method makes mud become harmless in low cost and high efficiency.

Description

technical field [0001] The invention relates to a sludge resource utilization technology of an urban sewage plant, in particular to a treatment method for inactivating pathogens in the sludge. Background technique [0002] With the development of my country's economy and the progress of urbanization, the sludge produced by urban sewage plants will also increase significantly. According to statistics, the amount of dry sludge produced in my country every year is about 5 million tons, and Shanghai alone produces more than 50,000 tons of sludge with a moisture content of 99% every day, and it is on the rise; on the other hand, the amount of dry sludge that can be used for planting Soil resources are very scarce. Therefore, land use of sludge is one of the cost-effective disposal methods to solve the sludge outlet. However, pathogens and other potential ecological risk factors must be eliminated before sludge land use. At present, the commonly used pa...

AI Technical Summary

Problems solved by technology

[0003] High-temperature drying has been done a lot of research at home and abroad. The drying methods include hot air drying, gas infrared drying, and electric heating drying. The time required is related to the drying temperature, but this method has great defects: first, it requires high temperature resistance of equipment materials, and the energy consumption of heating and stirring is large; at the same time, the volatile sludge in the sludge during the drying process Sexual organic substances escape together with water vapor, which is likely to cause secondary pollution

The results of actual operation show that alkali stabilization can quickly inactivate pathogens in sludge (about 2 hours), but this method itself also has defects: the pH of sludge after alkali stabilization is too high, and its properties are unstable. Follow-up treatment is required, otherwise the land cannot be used; the physical and chemical properties of lime-stabilized sludge will change, and when it is applied to the land for utilization, it will cause soil compaction, and because there is no reduction, it will instead increase the area of ​​sludge piles and transportation costs; the cost of ammonia gas is relatively high, and the remaining ammonia gas also needs to be disposed of, and ammonia gas leakage is likely to cause accidents

Because the sludge is rich in organic matter, these composting processes have common defects: A) the composting is not uniform, and the pathogens on the surface of the compost will proliferate, which cannot guarantee the inactivation of the pathogens; B) the viability of the dominant microbial population is relatively low. Weak, relatively affected by the ambient temperature, the treatment period in summer is not less than 20 days, and the treatment period in winter is not less than 30 days; C) The composting process has poor odor suppression effect, and it is easy to emit malodorous gases; D) Static composting The temperature rises slowly, which cannot meet the requirements of pathogen inactivation; the dynamic composting equipment is complex, and there are certain problems in the oxygen supply conditions, such as the use of perforated tubes at the bottom for oxygen supply, uneven mass transfer, easy to block, and may cause secondary pollution caused by leachate

Although anaerobic digestion and ultrasonic treatment also have certain bactericidal effects, they all have shortcomings such as incomplete sterilization or poor operability.