Research On High Efficiency Dewatering And Disposal Of Sludge

In recent years,a large number of sewage treatment plants are built and how to treat sludge produced in plants has become an increasingly outstanding issue.Sludge disposal is being focused gradually.The relevant policies and standards have been introduced,and the market scale is gradually promoting.Sludge not only contains organic matter with potential values,such as N,P,K and various trace elements,but also contains pathogens,heavy metals,dioxin and other toxic substances.Therefore,the process of sludge disposal should be selected according to the content of hazardous substances.As pretreatment,dewatering and drying technology is the premise and foundation of sludge disposal.This paper aimed to study sludge safe disposal and resource utilization,and explore sludge dewatering and drying process first,the main contents included: the improvement of sludge dewatering efficiency by using high efficiency filter aid,and the drying effect under different conditions were studied;Then,sludge-derived fuel was prepared by using the low-cost dewatering and drying results,and the performance test and mixed incineration were also carried out;finally,the effect of sludge aerobic biological treatment,application amount of sludge nutrient soil and improved formula were studied.Through the above research,our results indicate that the use of high efficiency filter aid could effectively improve the dewatering performance of sludge.The dewatering time was shortened by 1/4~1/3,and the water content of sludge cake could reach about 50%.The performance of sludge-derived fuel was the best when the material ratio was 1: 2,the ratio of diameter to height of the hole was 0.44,the particle size of straw was 5cm,and the addition of desulfurizer was 1%.The use of sludge-derived fuel in waste incineration under the conditions of oxygen-rich could effectively improve the combustion temperature and degree,reducing the emissions of gaseous pollutants,but the better mixture of oxygen and material was needed.Operation results of demonstration project showed that the sufficient sludge-derived fuel could increase power generation capacity by 10.9%,and lower dioxin and other pollutants.The adding of complex bacteria and amendments in municipal sludge aerobic treatment could help to increase the temperature of aerobic treatment,increase the rate of water loss and accelerate the degradation of organic matter.Critical amount(volume ratio)of sludge nutrition soil in garden greening was 20%;When the material ratio of sludge nutrition soil: desulfurization gypsum: peat was 50% to 60%: 30% to 40%: 5% to 15%,salt of saline alkali soil could be reduced,sludge nutrition soil played a key role in the process of improving coastal saline soil and the sludge in the gulf.