Study On Separation Treatment Of Alkali Wastewater And Conventional Printing And Dyeing Wastewater

The printing and dyeing process is complicated,and the water quality of different processes is very different.Conventional printing and dyeing wastewater,such as dyeing wastewater,rinsing wastewater and mercerized wastewater,have high chromaticity,COD and salinity,the water volume is large and B/C is 0.2⁰.4 suitable for biochemical treatment.Alkali reduction wastewater is mainly produced by alkali reduction technology of strong alkaline hydrolysis polyester.The wastewater has high pH and high concentration of sodium terephthalate?DT?,small amount of water and low biodegradability.The traditional method is to combine alkali reduction wastewater with conventional printing and dyeing wastewater,but it often fails to reach the standard,corrode the equipment seriously,and improve the system load.In view of this,it is an inevitable trend to divide the alkali waste water with other processes during the process of printing and dyeing wastewater treatment.In this study,the dyeing wastewater of a printing and dyeing enterprise in Zhejiang was studied,the alkali deweighting of printing and dyeing wastewater are collectively referred to as traditional printing and dyeing wastewater.The enterprise adopts the traditional physicochemical-biological-float printing and dyeing wastewater treatment process.The regulation pool,the initial sink and the water quality of the final sedimentation tank were monitored by conventional indicators.The results suggested that before source separate the final pond effluent COD,NH₃-N,TP respectively is 227.849 mg/L,3.819 mg/L and 0.394 mg/L.The COD is difficult to meet the?GB 4287-2012?water quality discharge standards.In view of this,the alkali deweighting wastewater points with conventional printing and dyeing wastewater treatment,including separate collection,alkali deweighting wastewater using multistage materialized biological coupling technology for processing,and the conventional printing and dyeing wastewater mixed collection,unified the original wastewater treatment process were used to determine the processing,the points after processing of conventional dyeing and printing wastewater treatment system of effluent COD concentration decreased to82.5 mg/L,NH₃-N and TP concentration is 0.58 mg/L and 0.22 mg/L.It can achieve the standard discharge of wastewater.The results showed that soluble organic functional groups are mainly composed of carboxyl carbon in conventional printing and dyeing wastewater treatment,and microbes play a major role in the wastewater treatment process,aerobic microorganisms can be efficiently carboxyl carbon into the hydroxyl and carbonyl carbon.The removal rates of dissolved organic carbon?DOC?and aromatic organics were 82.9%and 76.7%respectively.The organic compounds in printing and dyeing wastewater mainly include tryptophan and the by-product of dissolute micro organisms.The molecular weight distribution is between 30 and 2000Da,and the hydrolysis acidification can effectively transform and degrade the macromolecules,providing a good basis for the aerobic phase.Some large molecular organic compounds can also be removed by coagulant coagulant.The results of GC-MS showed that 12 PAHs were detected in printing and dyeing wastewater.Multistage physiochemical and biological process was used to separately treat alkali reduction wastewater.The results showed that COD,UV₂₅₄and TOC could remove efficiently by this process,and the removal rate was 98.4%,84.45%and 92.9%,respectively.The major ingredient was terephthalic acid?TA?after hydrolysis,and the removal rate was 99.64%.From 3DEEM and molecular weight distribution we concluded that alkali reduction wastewater was mainly composed of protein and little humic acid,and the relative molecular mass mainly distributed in 400-600.The results of infrared and ultraviolet properties indicated that the organic functional groups in the waste water including esters,carboxylic acids,alcohols,aromatic and hydrocarbon.The anaerobic oxidation and advanced oxidation can change the DOM groups,skeleton structure and improve the water biochemical characteristic.The points after source separation,alkali deweighting wastewater and conventional processing,printing and dyeing wastewater are efficiently effluent can reach the textile dyeing and finishing industrial water pollutant discharge standard?GB 4287-2012?water quality discharge standards.Source separate with targeted strong,stable operation,flexible operation,system impact resistant ability,and it will provide similar wastewater treatment process with a certain reference value.