Preparation Of Low Environmental Impact Of Light Sludge Ceramsite

With the rapid development of China's economy,sludge has become one of the solid wastes to be solved urgently.In addition,the idea of“attaching more importance to sewage disposal than sludge treatment”in China's sewage treatment industry has made the capacity,technology and investment of sludge treatment lag behind the sewage treatment industry seriously.Sludge contains a lot of harmful compounds,which may cause serious damage to our surrounding environment if not handled properly.This paper uses sludge and fly ash of Nanchang Wastewater Treatment Plant,water plant,paper mill as the main raw materials for the experimental study of firing ceramsite.Through the determination of the inorganic components of raw materials and the principle of Riley three-phase diagram,it is believed that fly ash and three kinds of sludge can be used as raw materials theoretically for firing ceramsite.Moreover,through heavy metal determination and leaching toxicity experiments on three sludge raw materials,it is concluded that,as raw materials for burning ceramsite,the three types of sludge substantially do not have the risk of heavy metal pollution,which is in line with the concept of environmental protection in China.Through the theory and formula screening test,the optimal formula and optimal process conditions for firing ceramsite in the experimental range were obtained.The optimum ratio of ceramsite to fly ash is 38.4%,the sludge content of the water plant is 57.7%,and the sludge content of the paper mill is 3.9%,through which the ceramsite has the lowest water absorption,the highest true density,and the compressive pressure.The optimum firing temperature is set to be around 1150?,and the main mineral components of the fired ceramsite are quartz,anorthite and mullite,of which mullite plays a major role in the hardness of the ceramsite.In view of the high organic content in the sludge,sludge will produce a large amount of SO₂,dioxins and other toxic and harmful gases in the process of drying,and this stage is the most obvious stage of producing benzene series.The benzene series produced in the sludge-making process was studied in this paper.Firstly,the adsorption and desorption conditions of the benzene series were determined at 300?preheating temperature,the adsorption time was 20 min,the adsorption amount was150 mg,the desorption time was 30 min,and the desorption amount was 1mL.Through experiments,the release rate of benzene series of different raw materials was studied and concluded that the detection rate of benzene was 100%,the release amount was basically stable at 0.06⁰.12g/L,the detection rate of toluene was53.3%,and the release rate of Group 16 was the largest one,followed by Group 12,the release of toluene from other components was stable at 0⁰.04g/L;the detection rate of ethylbenzene was 93.3%,and the release amount was in the range of0⁰.016g/L;The detection rate of o-xylene was the lowest,33.3%.The health risk assessment of the produced benzene series shows that the carcinogenic risk value caused by the toluene released by benzene and some components exceeds the acceptable range of carcinogenic risk,so the preheating temperature of the sludge during the firing of the ceramsite should be more than 300?,which can greatly reduce the release of benzene and the health risks;Regardless of the carcinogenic risk value or non-carcinogenic risk value of benzene,the risk index of women is higher than that of men,so women should focus more on the protective measures in this environment.All non-carcinogenic risk indices caused by benzene derivatives released under these conditions do not exceed acceptable non-carcinogenic risk values.