Pilot-scale Study On Treatment Of Dewatering Liquid Of Sludge Carbonization By MBR And Forecast Of Effluent Quality By Neural Network

With the development of sludge treatment and disposal technology,a new sludge condition technology—sludge carbonization technology has already started pilot project in some place of China. The centrifuge of sludge carbonization technology can produce a large number of dewatering liquid.The dewatering liquid is a kind of new industrial waste water so there’s no treatment experience to it.To provide experiment data and experience to a sewage treatment plant in Shanxi where MBR process will be built to treat dewatering liquid,the experiments make comprehensive studies in technological process, process parameters, treatment effect, possible problems and the model of water quality prediction.The discharge schemes of effluent in this experiments are direct discharge and indirect discharge.The direct discharge scheme can refer to “Discharge standard of pollutants for municipal wastewater treatment plant(GB18918-2002,direct discharge standard for short)” and the indirect discharge scheme can refer to “Wastewater quality standards for discharge to municipal sewers(CJ343-2010, indirect discharge standard for short)”.In the study of dewatering liquid treatment process by flocculent settling-MBR-NaClO,the results show that in the carbonization sewage the pollutants exceed the standard seriously. The water quality of carbonization sewage changes in a large range.In the dewatering liquid, the pollutants exceed the standard seriously and the water quality of dewatering liquid changes in a large range. But the biodegradability of dewatering liquid is strong. Polyferric sulfate is elected to be flocculant after the flocculation test because of the economic factors.The results of a continuous flow test in flow of 160L/d show that the removal rate of COD is from 86.08% to 88.30%, and the removal effect of COD is stable.But the effluent in this experiments can’t be discharged because of the substandard water quality. The results of a continuous flow test in flow of 290L/d show that the removal effect of COD is stable but the removal rate of COD is from 39.19% to 51.30%.The effluent in this experiments can’t be discharged because of the substandard water quality. NaClO shows a certain degree of degradation of COD in the continuous flow test in flow of 160L/d. The maximum COD degradation amplitude can reach 220mg/L and the removal rate of COD is 28.35% when the dosage of NaClO reaches 25 ml. The effluent in NaClO treatment experiments can’t be discharged because of the substandard water quality.In the study of dewatering liquid treatment process by dilution-MBR-NaClO,the results show that when the dilution factor reaches K1 and K3,the COD concentration can achieve the Grade III standard of direct discharge standard.When the dilution factor reaches from K1 to K11,the COD concentration can achieve the Class A standard of indirect discharge standard for short.When the dilution factor reaches K5,K6,K7 and K10,the ammonia nitrogen concentration can achieve the Grade II standard of direct discharge standard. When the dilution factor reaches K5,K6,K7,K8,K10 and K11,the ammonia nitrogen concentration can achieve the Class A standard of indirect discharge standard for short. The fitting result of COD removal process is a zero order reaction kinetic equation and NaClO decolourizing process is a Two order kinetic equation. The regression equation of COD and chroma removal process is a three order equation.In the continuous influent test,when MLSS keeps from 2700mg/L to 4200mg/L, the removal rate of COD keeps at a high level(70%). In the premise of the COD concentration achieves the Class A standard of indirect discharge standard for short,the maximum COD volume load that the system can resist is 0.46kgCOD/m3 aeration tank ?d and the maximum COD sludge load the system can resist is 0.17kgCOD/kgMLSS?d. In addition,NaClO can make the concentration of COD, ammonia nitrogen and chroma of effluent achieve the two standards.According to the GC-MS analysis of influent and effluent, the organic compounds of dewatering liquid contain thiols, isothiocyanic acids, ethers, glycosides and ketoximes.Among them, methyl isothiocyanate and tert-Butyl methyl ether are two toxic compounds.After the treatment of dilution and MBR,the effluent of the system is safe and non-toxic.In the study of water quality forecast based on the AGNES-BP neural network,the results show that the AGNES-BP neural network whose parameters are oxygen concentrations in the water,MLSS,COD concentrations and COD volume loads can forecast the effluent quality in a high-precision level.The AGNES-BP neural network can be a auxiliary forecast mothed of Operation controlling and simulation in the future.According to the observation and analysis on the plankton in the experiments,the possible reasons of daphnia outbreak are the warm climate and the low COD sludge load. There are large differences in the morphology of daphnia and Black worm.But in the aspects of foods, oxygen demands and ambient temperatures,the two species have intersections.From the method of deinsectization, the common chlorinated lime can kill the two living beings.