Surplus Sludge Quickly Reduction And Stabilization

The remainder of the urban sewage sludge treatment and disposal hasbecome an urgent need to address environmental problems. Solving the poorsludge cannot be fundamentally improved water environment. This paperintroduces the development of thermal hydrolysis, principal and the latestresearch process. On the basis, the experiments used high temperature and highpressure reactor dealing with dewatering sludge, factors about temperature,pressure, reaction time, catalyst, source of sludge, heating mode and pretreatmentwere studied in dried sludge and liquid supernatant. Simultaneously, thestabilization method of heavy metals in the urban sewage surplus sludge has beensuccessfully constructed. The effect of curing agent, curing time and curing ratioon the performance of scraps of heavy metal state were investigated. Theexperiment was to lay a foundation for thermal hydrolysis treating sludge and findthe best working condition. The results were as follows:Thermal hydrolysis could quickly change sludge structure, and reduce themoisture content of sludge through the mechanical dewatering. The organicmatters experience dissolved and hydrolysis. The change trend of differentsources of sludge was consistent, the higher temperature, pressure and time, thelower of moisture content. Orthogonal experiments showed that the bestprocessing condition was temperature234℃, pressure3.0MPa, reaction time30min. The moisture content in steam heating condition was lower than that inelectrical heating condition, the lowest was48.01%, each index of liquidsupernatant was low. After pretreatment, the dewatering performance of sludgewas better, the lowest moisture content can be40.36%.Stabilization agents had effect on heavy metals in the sludge. Thestabilization effect of Pb was better than that of Cu, the lowest stability rate of Pbwas27.58%, the highest was58.71%, the lowest stability rate of Cu was9.96%,the highest was35.12%. The longer stabilization time, the more stabilization dose,the stabilization effect was better. The effect of lime was poorer than calcium slag,but with the increase of stabilization time, the effect of lime would be close to theeffect of calcium slag.The research results showed that using thermal hydrolysis can achieve the targets of rapid reduction and stabilization. And there were a variety of outlets fordry sludge. Thermal hydrolysis can quickly realize the reduction of sludge. Thefurther application of this technique would have a promising future.