| Coking wastewater comes from the process of gas purification, coke making or coking product collection. Due to the different procedures and methods of coking products manufacture, the composition of coking wastewater is very complex and it is also difficult to handle the coking wastewater. The main composition of coking wastewater are phenol, m-cresol, quinoline, and another heterocyclic compounds, the concentration of them are very high. All of them are difficult to be used in biochemistry and harmful to humans and environment. The biodegrability of Coking wastewater is goodish, it has been a severe problem in the field of wastewater treatment. In this study, in the aim of innocuous treatment of coking wastewater with high cost effective, a novel treatment process based on bioaugmentation was developed.Two high concentrated phenol-degrading strains, JH6 and JH8, were isolated from activated sludge and identified as Paecilomyces variotii JH6 and Candida tropicalis JH8 based on standard morphological and phylogenetic analysis of ITS1-5.8S rRNA gene-ITS2 DNA and 26S rDNA D1/D2 sequence.The effects of various abiotic factors, such as temperature, pH and added glucose concentration were evaluated on the biodegradation performance of phenol by strain JH6 and strain JH8. In our work, it was presumed that the aeration provided by shaking the flasks was able to keep the oxygen concentration sufficient, the kinetics of phenol removal was investigated in a batch reactor. The kinetics was described using the Haldane-type kinetic models, with model constants ofμmax=0.345/h, Ks=180.4 mg·L-1, Ki=286.78 mg·L-1 for strain JH6 andμmax=0.318/h, Ks=95 mg·-1, Ki= 480 mg-L-1 for strain JH8.The phenol degradation by strain JH6 and JH8 was also tested in the presence of m-cresol, quinoline and Cr+6 as these toxicants are usually present along with phenol in industrial wastewaters. In the presence of 600 mg·L-1 phenol,200 mg·L-1 m-cresol was removed completely by strain JH6 within 72 h, and the degradation ratio of 200 mg·L-1 quinoline was as high as 80.4%. The presence of m-cresol and quinoline did not inhibit the biodegradation of phenol by C. tropicalis JH8. But only 73% m-cresol was removed after 32 h, whereas quinoline was not degraded even after 40 h. This paper demonstrates that phenol can be used as single carbon source for Cr(VI) reduced to Cr(III) under aerobic cnditions by strain JH6 and JH8.The bioaugmentation system coupled specially efficent microorganism with activated carbon fiber- aerated biofilm reactor was constructed through inoculating Paecilomyces variotii JH6. After startup, the phenol load increased gradually. For the analysis of experimental results, different mathematical models, including second-order kinetic model and Stover-kincannon model were applied to the reactor at different phenol concentration of influent and HRT. The kinetic constants of Stover-kincannon model were determined as follows:Umax=47.85 g·L-1·d-1, Kb= 48.11 g·L-1·d-1. The activated carbon fiber- aerated biofilm reactor, which inoculating Paecilomyces variotii JH6, was used to treat coking wastewater. The results shows it is feasible in technique. It further indicated that under the optimal operational conditions, the phenol, m-cresol, quinoline and COD were removed effectively. The indexes of effluent were lower than the discharge standard of water pollutants for iron and steel industry (GB 13456-92).In conclusion, the combined process contained activated carbon fiber- aerated biofilm reactor, which is based on the application of bioaugmentation, is promising for the economic, effective and innocuous remediation of coking wastewater.
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