Study On Process For Printing And Dyeing Wastewater Based On Advanced Biological Carrier

With the most stringent green policies and the targeted emissions standards, textile industry is facing more difficult of the environmental protection pressure. Dyeing and printing industry are badly in need of highly efficient and stable wastewater treatment processes to ensure the sustainable development. New biological carrier was developed with basalt fiber which is a high performance material of environment friendly, including of the structures of carrier and preparation methods in this study. What’s more, the basis performance of this new carrier was studied experimentally. By means of setting up biological contact oxidation process with basalt fiber carriers, the effect of operation parameter on wastewater treatment was further studied. According to the emissions standards of actual printing and dyeing wastewater, the composed process of Fe-C micro electrolysis and high performance contact oxidation is applied to treat printing and dyeing wastewater. Study results are as follows:(1) The basalt fiber after activated would be twisted and clamped by hand into the fold of two single-core cable center in the middle of the rope, by reversing the cables to fix the basalt fibers into a spiral structural. With this design the seat carrier was indirectly fixed on the filler bracket to form a fixed packing bed, further to form integrated structure. Based on the carrier the contact process was built to treat printing and dyeing wastewater. In the experiment, the speed of biofilm formation and the influence of several factors on removal rate of COD and chroma from printing and dyeing wastewater such as HRT and pH were researched. The results showed, when the HRT was 34 h, the COD removal rate was not exceed 70%, while HRT= 39 h, the COD removal rate can be stable at more than 85%. The best suitable pH ranged from 7 to 7.5, at this scope, the COD removal rate was as high as 89.5%. However, the contact oxidation process based on the spiral of basalt fiber carrier to treat printing and dyeing wastewater, the chroma removal effect was poorer, which was not more than 50%.(2) The stacked high performance carrier would be made of individual pieces of fiber alternative arrangement in the center of steel wire rope. The results of experiment on mass transfer performance of the reaction tank installed stacked carrier showed that the most affected by the filing ratio was elastic filler, the basalt fiber was second. Contact oxidation tank containing basalt fiber carrier, compared with no packing, the maximum oxygen mass transfer coefficient increased by 137%, after the 150% of the elastic filler, superior to 122% of the combined packing. The stacked basalt fiber carrier had fast speed to form biofilm, and the membrane volume was high, the biofilm weight in 90-150 kg/m3, the life was quite rich.(3) Aiming at the characteristic of the quality of printing and dyeing wastewater, a composite process characteristics contact oxidation technology installed with stacked basalt fiber carriers as the core processing unit, the iron carbon micro electrolysis as the pretreatment process was built. In this paper, the operation processes of each processing unit parameters were studied. The results showed that the iron carbon micro electrolysis optimal operation parameters was micro oxygen aeration, water pH was 4.5, the reaction time wasl h. And contact oxidation process optimal operation parameters was the hydraulic retention time of 12 h, water pH was 7.5, the DO for 2-3 mg/L.(4) Under the best process parameters, the iron carbon micro electrolysis stacked basalt fiber contact oxidation process to treat printing and dyeing wastewater was operated dynamic operation. The test indicated that each processing unit to treat printing and dyeing wastewater had stability of the removal rate of pollutants and the combination process effluent meet the textile dyeing and finishing of industrial water pollution discharge standards (GB4287-2012) "the pollutant emissions limits.Anyhow, in practice, it proved that Fe-C micro electrolysis-contact oxidation process was simple flow and high treating efficiency to treat printing and dyeing wastewater. At the same time, this process is valuable to promote in printing and dyeing wastewater treatment.