Study On Parameters And Engineering Design Of Printing And Dyeing Wastewater Treatment By Anaerobic-A/O Process

Printing and dyeing wastewater has the characteristics of high organic content,high salt content,poor biodegradability and high chroma.In this study,the printing and dyeing wastewater produced by Hebei Sanli Wool Textile Co..The effects of HRT,filler type and reflux ratio on the treatment effect of anaerobic-A/O process reactor were studied by using simulated printing and dyeing wastewater.The effect of anaerobic-A/O process reactor was monitored by COD,TN,NH₄⁺-N,chroma,aniline and other indicators.Then,we use the actual printing and dyeing wastewater to verify the treatment effect of the anaerobic-A/O process reactor,and the abundance and diversity of the microbial community in the reactor were studied after the operation was stable.In the end,we design the anaerobic-A/O process according to the parameters of the pilot test.The start-up of the anaerobic-A/O process reactor was divided into three stages.After stabilization,COD of influent water is 1600 mg/L,while the COD of effluent water is 63 mg/L,COD removal rate reached 96%,chroma removal rate is 79%.After the start-up,we optimized the parameters such as the hydraulic retention time,packing and reflux ratio.When HRT was 48 hours,the best removal efficiency was obtained.The removal efficiency of COD,NH₄⁺-N and chroma were 95%,82%and 79%,respectively.The amount of aniline produced was 0.52 mg/L.Under the optimal HRT condition,the effect of packing on the reactor was studied.The results showed that the removal efficiency of COD,NH₄⁺-N and chroma was 98%,94%and 85%,respectively,and the amount of aniline was 0.48 mg/L.Then the effect of reflux ratio on the reactor was studied under the optimal HRT and packing conditions.The results showed that when the reflux ratio was 1,the removal efficiency of COD,TN,NH₄⁺-N and chroma were 92%,68%,94%and 80%,respectively,and the amount of aniline was 0.42 mg/L.After the study of simulated wastewater,under the optimal conditions,the effect was verified by the actual printing and dyeing wastewater.The removal efficiency of COD,TN,NH₄⁺-N and chroma were 87%,67%,96%and 67%,respectively,and the amount of aniline was 0.78 mg/L.High throughput sequencing showed that the richness of the microbial community in the middle of the anaerobic pool was lower than that in the bottom,while that in the anoxic pool was the lowest,and that in the aerobic pool was significantly higher than that in the anoxic pool.The diversity of microbial community in the bottom of anaerobic tank was greater than that in the middle of anaerobic tank.The diversity of microbial community in aerobic tank was greater than that in anoxic tank.At the gate level,the main species of the reactor are Proteobacteria,Bacteroidetes,Chloroflexi,Firmicutes,Actinobacteria.Proteobacteria and Bacteroidetes have nitrification.Bacteroidetes is the main class of hydrolytic acidification and denitrification.At the genus level,the main species of the reactor are Enterobacter,Candidatus＿Microthrix,Lactivibrio and Desulfovibrio.Enterobacter can be decolorized and hydrolyzed.In general,the anaerobic-A/O process reactor can effectively reduce the index of printing and dyeing wastewater produced by the factory.The anaerobic-A/O process is suitable for the treatment of printing and dyeing wastewater produced by Hebei Sanli Wool Textile Co.,Ltd.