The Sludge Fuel Technology For Municipal Sewage Treatment Plant Sludge

The production of municipal sewage sludge is huge and the component is complex,how to deal with them effectively has been drawn more and more attention currently. Theorganics in sludge contains huge energy, and the sludge fuel technology will be realizedby making full use of the energy, which can bring about notable economic andenvironmental benefits. The problems of present sludge fuel technology are the largeenergy consumption and high operation cost, it restricted the development of sludge fueltechnology. The purpose of this study is to provide a kind of sludge fuel new technology,which has low energy consumption, short treatment time and a low cost of the treatmentprocess, in order to solve the problems of secondary pollution, huge energy consumptionand high operating costs in the sludge treatment process of city sewage treatment plant.The major problem of restrict sludge fuel technology is the most energy consumptionin the production process used for sludge dehydration. In order to solve this problem,mechanical dehydration method is used to removal water as much as possible beforedrying the sludge. Because the water is difficult to be removed, sludge conditioning mustbe put into practice before mechanical dehydration, then the water is more easily to remove.This paper carries out joint conditioning experiment for dewatered sludge of municipalsewage treatment plants with many kinds of conditioning methods. The results show thatthe moisture content of sludge cake can be reduced to below60%after mechanicaldehydration. The best condition is that every kilogram of sludge adds cationicpolyacrylamide(CPAM)3.5~4.0g, cationic surfactant(cetyl trimethyl ammonium bromide,CTAB)4.0~4.5g, skeleton builders (sawdust)110~130g, the power of microwave is600W, microwave irradiation time is250~300s。Microwave heating technology was adopted in this study for heating and dryingsludge, the time of microwave drying is greatly shortened compared with conventionalheating, and the energy consumption is reduced significantly. The results of microwavedrying experiment show that the microwave energy utilization rate can be increasedfurthest by the appropriate of microwave power and microwave radiation time.The sludge fuel process determined by this study can get the finished sludge fuel in a relatively shorter time. The water content of the sludge fuel is5%~10%and the calorificvalue is4000~5000calories.This treatment process can save nearly400yuan every tonneof wet sludge compared with other sludge fuel process, the cost of sludge fuel process isgreatly reduced.