Study On Treatment Of Printing And Dying Wastewater With The Hydrolysis-Membrane Bioreactor

With the vigorous development of printing and dyeing industry in ourcountry, the amount of wastewater emitted from printing and dyeing excessesone billion and seven hundred million m3 per year. Printing and dyeingwastewater from the textile industry contains a variety of chemicals. Thewastewater is deep color and difficult to be treated. There are characteristics ofhigh concentration contaminants, complex composition and variation waterquality in dye-printing wastewater. Due to the harm to the environment andhuman, more and more attentions are being paid. The treatment of printing anddyeing wastewater has become one of the most important research fields ofenvironmental protection.Printing and dyeing wastewater has become one of wastewaters which arethe most important and difficult to treat for the high cost of physical-chemicalmethod and low efficiency of treating by only one biological method. We use anew method which treats dyeing wastewater by a new kind of process ofhydrolysis acidification-MBR in this dissertation. The first stage is Up-flowAnaerobic Sludge Blanket reactor (UASB) and the Anaerobic Baffled Reactor(ABR) of this experiment which can improve the property of biodegradation inwastewater and creates a favorable condition for the second stage in which theMBR aerobic oxidation happens. The parameters such as COD, BOD5, pH,chromaticity, SS, DO have been monitored, controlled and studied.The final purpose is to find a method which is high efficient and low costto treat dye -printing wastewater. I want to confirm the best situation byexperiment.The content of the experiment is depicted as follows: 1,Cultivate the anaerobic and aerobic sludge , then study the speedingstartup situation of UASB,ABR and MBR reactor.2,In the debugging stage, I confirmed the prime running conditions ofhydrolytic-acidification by changing the HRT, pH and temperature.3,Changing the value of DO, pH, temperature and HRT in the Membranebioreactor, to confirmed the perfect conditions for running.4,In the prime running situation of the experiment, I obtained the perfecteffect of treating dye -printing wastewater by measuring the COD , NH4+-N,BOD5 and the chromaticity of the inflow or outflow. Through comparingUASB-MBR to ABR-MBR, the experiment obtained the feasibility, primesituation and the effect.We can draw the following inclusions by study on treatment of printingand dyeing wastewater with the hydrolysis-membrane bioreactor.1,The UASB reactor has good effect in treating the printing and dyeingwastewater. While the temperature between 25~30℃, HRT between 6h~8h,and the water pH value adjusted at 6.5~7.5, the average COD value of theprinting and dyeing wastewater drops from 4105mg/L to 2950mg/L,averageremove rate of the UASB reactor is 26%, the property of biodegradation inwastewater is distinctly enhanced after the hydrolysis acidification function,the BOD5/COD value rises from 0.1 to 0.3, the chromaticity obviously reduces,dropping from 600 to 40, and the character of the effluent is quite stable.2,The ABR reactor has better treatment effect than the UASB reactor intreating the printing and dyeing wastewater. While the temperature between25℃~30℃, HRT between 12h~14h, and pH of the inflow adjustment in6.5~7.5, the average COD value of the printing and dyeing wastewaterdropping from 4105mg/L to 2670mg/L, the average remove rate is 32%,BOD5/COD value rises from 0.1 to 0.45, the chromaticity obviously reduces, drops from 600 to 20, and the character of effluent is quite stable. HRT, thetemperature, pH are the main factors which effect in treating printing anddyeing wastewater by UASB and ABR reactors.3,Through the research of the MBR's starting-up phase, the MBR notonly has the high organic matter removal rate, but also has the quickadjustment ability. The membrane bioreactor achieves more than 90% in theCOD removing efficiency. The effluent quality is good. The treatment mainlydepends upon the microorganism's adsorption degeneration function. The filmis quite small in the COD removal function, and it only occupies 10% of theentire removal.4,The prime situation of MBR is that pH is between 6.5~8.5, DO isbetween 3.5mg/L~4.5mg/L and the temperature is between 20~30℃. When theHRT is 8h the contamination can be well removed. The COD of the influent isabout 2600mg/L~3200mg/L and the COD of the effluent is below 300mg/L;the average removal rate is 90.2%;MBR can remove 60% chromaticity andNH4+-N in the influent and the effluent is 55~60mg/L and 4~8mg/ L, theremoval of the NH4+-N is above 90%, and the qualities of the effluent is alsovery stable.5,The whole system maintained a high removal rate of contamination.The whole system maintained a high removal rate of contamination. The CODof the experimental wastewater is 3500~4500mg/L. The COD of the effluentfrom UASB-MBR is 120~150 mg/L and the average removal rate is 90.5%,atthe same time the COD of the outflow from ABR-MBR is 80~100 mg/L andthe average removal rate is 96.4%. The treatment effect of NH4+-N is also good,the NH4+-N in the influent and effluent are 55~60mg/L and 4~8mg/L and theremoval rate is above 90%. The chrominance of the effluent from MBR isbelow 50 times. The qualities of effluent from two kinds of processes both meet first level of GB4287-92. So the application of hydrolysis-membranebioreactor to treat printing and dyeing wastewater is feasible, the running statusis all right and the ABR-MBR is better than the UASB-MBR process.