Experimental Study On Co-Bio-drying Of Sewage Sludge And Kitchen Waste

With the rapid increase of the sewage sludge and the continuous growth of the urban kitchen waste, the treatment and disposal to make them harmless resources is extremely urgent. The characteristic of the sludge is high moisture content, abundant microbes. The main purpose is to reduce and stabilize, therefore, the drying dehydration of the sludge is a major research direction. And the characteristic of the kitchen waste is high moisture content, high content of organic matter, easy biodegradation, which makes harmless disposal be a major research content. Compared with the traditional thermal drying processing, bio-drying method as a new processing technology has the characteristics of energy conservation and environmental protection, is getting more and more attention. The traditional treatment method of the sludge and the kitchen waste is to dispose separately; however, this study used combined bio-drying method to dispose the sludge and the kitchen waste. On the one hand, it can make use of the easily degradable organic matter of the kitchen waste to provide nutrients for sludge microorganisms; on the other hand, large amounts of microbes of the sludge can inoculate for the biodegradation activities of the kitchen waste. Through the coupling effect of the both, it can produce a large number of biological heat in a short time. In the end it not only removed a lot of water in the sludge, but also degradated the perishable organic matter of the kitchen waste, which also reached the purpose of sludge decrement and kitchen waste harmless. Through the combined bio-drying of the sludge and the kitchen waste, it not only greatly improved the drying effect, and simplified the process, but also achieved the purpose of energy conservation and environmental protection. This research work mainly included:①esigned the associated bio-drying test apparatus, installed and debugged;②esigned experiments to analyze the combined drying effect of different sludge added quantity, determined the optimal sludge content;③esigned experiments to analyze the combined drying effect of different initial moisture content, determined the optimal initial water content;④esigned experiments to optimize in the original material of the combined bio-drying, obtained the optimization parameters, including the types of the conditioner and particle size, and analyzed the test mechanism;⑤esigned experiments to optimize in the operation process of the combined bio-drying, obtained the optimization parameters, including ventilation of gas, ventilation rate and turning, and analyzed the test mechanism. Through the combined bio-drying experiments of the sludge and the kitchen waste, the results were as follows:①hrough designing and debugging the reactor, improved the condensate collection system and thermal insulation measures;②hrough the sludge amount contrast test, the results showed that the heating rate of500g sludge test group was fastest, the peak temperature was highest, and the moisture content of the material decreased by3.40%;③hrough the initial moisture content contrast test, the results showed that the warming effect of the initial moisture content of71.7%test group was best, the peak temperature was highest, and the moisture content of the material decreased by4.25%;④hrough the optimization of the initial material, drew the conclusion:straw is better conditioner, which heating rate is the fastest and the highest temperature is54.8℃. And the removal effect of moisture is obvious, the moisture content of the material decreased by13.05%; Compared with the material of6-10mm particle size, the temperature effect of the2-6mm particle size material is better, which moisture removal is faster;⑤hrough the optimization of the running process, we concluded that:compared with the normal ventilation, using preheated air ventilation, which temperature rose faster and high temperature duration was longer, can make the material moisture content fell more; adjusting the ventilation rate appropriately according to the temperature changed during the running process, helped to significantly strengthen the moisture removal efficiency; turning process can adjust the pore structure of the material, and then strengthened warming and water removal, but strengthening effect was not obvious.