Research On The Treatment Of Mixing Dyeing Wastewater Using Hydrolytic Acidiifcation-Contact Oxidation-BAF Process

Dyeing wastewater is always with bio-toxicity and poor biodegradability, belong to therefractory industrial wastewater. Study on industrial wastewater treatment of printing anddyeing wastewater is currently hot issue. Current printing and dyeing wastewater treatmentprocesses are mostly hydrolytic acidification-contact oxidation process.However poorbiodegradability and with a certain amount of printing and dyeing molecule which havebiological toxicity, therefore single treatment of printing and dyeing wastewater is hard ableto meet the emission requirements. Focus on the actual situation of a number of dyeingindustrial enterprises which in towns and villages, according to the total metabolic theory, weconsidered that mixed the domestic sewage with dyeing wastewater by a certain percentage toimprove the biodegradability of dyeing wastewater and the water quality after the treatmentof dyeing wastewater by biological treatment systems.This article looks at how different scales of dyeing wastewater intake have influence onperformance of biological reaction system. And compare the effluent water quality oftraditional A/O process with hydrolytic acidification-contact oxidation process on treatingmixed wastewater. Experiments in a60d running in the process of gradually increase theproportion of dying wastewater in simulation of wastewater inlet. And the results showed that,when the elevated proportion of mixed dyeing wastewater in mixed wastewater at40%, anaverage concentration of NH₃-N was14.82mg/L, the concentration of CODcrwas117.71mg/L, and chroma was250times in traditional A/O reactor effluent. Under the sameconditions, hydrolytic acidification-contact oxidation reactor in the proportion of40%dyingwastewater, the concentration of NH₃-N was4.97mg/L, the concentration of CODcrwas48.65mg/L, and the color of water was120times times. Indicating that hydrolysisacidification-contact oxidation process performed much better than the traditional A/Oreactor when treating simulated mixing wastewater. When using hydrolytic-acidificationreactor treating the mixing wastewater which including50%of dyeing wastewater, theaverage concentration of NH₃-N was8.80mg/L, the concentrations of CODcrwas77mg/L,and the chroma was200times in effluent. Continue to improve the ratio of dying wastewater,the effluent water quality was getting worse.The experiments that using Biological Aerated Filter （BAF） followed water hydrolysis acidification-contact oxidation process for advanced treatment show that, after BAF treatment,the concentration of NH₃-N, CODcrand chroma of the hydrolytic-acidification-contactoxidation reactor effluent reduced respectively. When treated by BAF reactor，averagedinlet concentration by NH₃-N9.01mg/L was reduced to2.00mg/L; averaged concentration ofCODcrof78.01mg/L was reduced to about30.00mg/L; and chroma declined from200timesto20times in the water. Shows that using BAF as further treatment to enhance theperformance of hydrolytic acidification-contact oxidation treatment facilities, can improveeffluent water quality to make sure it comform to the Standard of P.R. China, SyntheticalDraining Standard of Sewage,GB8978-1996. And when compared the performance of thebiomembrane in Biological Aerated Filter and conventional activated sludge of the A/Oreactor to degradate the effluent of secondary treatment, while maintaining the same biomassand same circumstances, we can find that biomembrane in Biological Aerated Filter to showmore strong ability on the degradation of certain non-biodegradable dye molecules. Alsosuggested that there was microorganism which was suitable for degradation of dyeingwastewater at start-up and operation stages of BAF.In order to meet the different technical requirements of engineering applications, wealso study on the ability of ozone oxidation for further treatment to degradate the effluent ofhydrolytic acidification-contact oxidation process. Researched on the preparation of catalyticozone oxidation catalysts and the use of ozone oxidation process to treat the effluent ofhydrolytic acidification-contact oxidation process. Contrasted the effects of active Al₂O₃,CuO-Al₂O₃, Fe₂O₃-Al₂O₃and Ni-Al₂O₃under the same preparating conditions as catalyst forcatalytic ozonation to treat secondary effluent from biological treatment, we find that thestrength of catalytic properties is: NiO>Fe₂O₃>CuO> active Al₂O₃> without catalysts. Andoptimized preparation conditions of Ni-Al₂O₃catalyst by orthogonal experimental design.Orthogonal experimental results shows that the influence factors of major and minor order is:calcination temperature> impregnating solution concentration> calcination time>maceration time; and the optimal catalyst preparation conditions is: impregnating solutionconcentration is3%, immersion time is4h, the burning temperature is450°c, burning time is3h. Preparated Ni-Al₂O₃catalyst under the conditions defined by the experiment, using it forcatalytic ozonation secondary effluent from biological treatment, and the water qualitysignificantly improved after the reaction, the pollutant concentrations are dropped as the prolonged reaction time. When kept ozone oxidation15min, the original concentration ofCODcrfrom84.22mg/L got down to50mg/L, the NH₃-N concentration of raw water from the10.88mg/L decreased to5.01mg/L, and the chroma had69%removed. And the effluent waterquality completely meet the Standard of P.R. China, Synthetical Draining Standard ofSewage,GB8978-1996.