Research On Pretreatment And Hydrolytic Acidification Of Wastewater Sludge For Methanation In Nucleotide Factory

With high-speed development of national economy, the amount of sewage in our countryhas increased dramatically. In the sewage treatment process, the byproducts increase sharply.Anaerobic digestion technology is the most widely used in sludge stabilization technology,but it has some problems such as long processing cycle and methane low yield.The purpose ofmost research is to enhance methane production, the hydrolysis of sludge acidification iscrucial factor actually, which is the restrictive step for anaerobic digestion. Therefore it is ofgreat importance to accelerates the hydrolysis process and raise release of organic matter forthe rate of biological transformation,resource utilization and minimization.Consequently, application of response surface methodology is to optimize the operatingconditions of the acidified activated sludge and get the best parameters in our study. It isnecessary for the wastewater sludge to do the fermentation hydrolysis test in the optimumconditions and to explore pretreatment method, temperature and initial pH of the hydrolysis ofsludge acidification.The mesophilic anaerobic digestion is adopted for the sludge in the study. Firstly, Thewastewater′s decomposition was studied by the influence of the comparative analysisof heat hydrolysis, alkali, ultrasonic separately, alkali and heat hydrolysis bases withultrasound combination.The results showed that the accumulation of biogas increased2.08times after treatment with alkali-thermal coupling,the concentrations of SCOD increased14.62times; solubility protein increased85.72times; VS removal rate increased2.02times.Based on the results, the way of the heat-the alkali coupled processing is chosen.Then We studied the effect of initial pH and hydrolysis temperature during the sludgehydrolysis process. The results showed that,the VS removal rate with the temperature55℃isbetter than others。Therefore,We limited the range of the hydrolysis temperature from45to65℃. While We also knew that,after24hours,the VS removal rate with the initial pH5is betterthan others。So We limited the range of the tinitial pH from4to6. Based on the analysis of the response surface plots and their corresponding contour plots,the effects of temperature, pH were explored.Results showed that the optimal hydrolysisiconditions of the temperature is54.97℃,and the pH value is4.52. In this case, the optimalhydrolysisi condition of VS removal rate was39.224%.Based on the optimization results ofrespose surface methodology, waste activated sludge was pretreated under the optimizedoperation parameters to investigate the acidification effect under anaerobicfermentation.Results showed that soluble protein concentration, SCOD concentration weremuch higher than that of the unpretreated sludge,respectively,the soluble protein is more than68.71times,the SCOD is more than18.45times.The results show that, in this condition,it canmake the sludge recycling and reduction come true to a greater extend。...