Research On The Treatmental Of High Concentration Coke-plant Wastewater By Bio-chemical Treatment

The component of coke plant wastewater are very complex. There are large amount of refractory organics in it, and their concentrations are high. Coke-plant wastewater mostly is treated by Bio-treatments in many coke plant, which conventional activated sludge(CAS) system in the highest flight. Even though the influent concentration is under 2000mgCOD/L after diluted, The CAS system can not effectively remove COD from the coke plant wastewater. Therefore, the effluent COD is 200~ 400 mg/L, and it is difficult to meet the state discharge standards (GB8978-1996). To find a treatment to biodegrade the coke-plant wastewater successfully, the pilot scale test on treating coke-plant wastewater without dilution by A~2O process with throwing bacteria, the effluent was not meet the state discharge standards. To improve the effluent wastewater quality, several preponderant bacteria was screened from the effluent to augment the treatment efficiency. The bioaugmentation is brought forward to uplift the biodegradability of refractory organics in coke plant wastewaterIn this paper, the pilot scale test was studied based the wastewater quality in Shijiazhuang Coke & Chemical Group(SCCG). A~2O process was studied with throwing preponderant bacteria to aerobic phase, which were screened from active sludge in SCCG's wastewater treatment plant. The process treated high COD concentration coke-plant wastewater without dilution, and it can reach the CAS's treatment efficiency at present. This process can saving water resources and reduce the treatment costs. The highest treatment efficiency was appeared in the anoxic phase where the average degrade rate for COD and NH3-N concentration can reach 71.3%, 56.9% respectively. During the 20 days' steady performance term, the average influent and effluent concentration is 5527.1mgCOD/L, 156.5mg NH3-N /L; 320.6mgCOD/L, 15.3mg NH3-N /L respectively. Except COD, NH3-N and chroma (200), other items detected can reach the state discharge standards. During the period of test, the process performance stabilization and can endure a certain extent impaction.For the quality of effluent from the test can't meet the state discharge standards, several kinds of refractory organics was obtained by GC-MS analyse in the effluentwhere quinoline and naphthalene was in the majority. So 4 strains of quinoline degradable bacteria and 2 strains of naphthalene degradable bacteria have been isolated from activated sludge at SCCG By the biodegradation ability experimentation, 4 efficiency preponderant bacteria were chosen. Through the static experiments for those bacteria, the effect throw single kind of bacteria, throw admixture of bacteria, Fe3+ and addition of bacteria for the effluent from the A2O process have been studied. The kinetic analyses of the degradation process and degradation mechanism were preliminarily discussed.The result of static experiments showed that throwing bacteria, Fe3+ and addition of bacteria, reform active sludge can improve the degrade rate for the post-treated coke-plant wastewater from A2O process. Throwing the mixture of bacteria into the reform active sludge can obtain the highest degrade rate—reach 70% after 48 hours. It can degrade the coke-plant wastewater to meet the state discharge standards.The systematically experimental research on A2O process with screening and throwing bacteria to deal with the refractory organics in coke plant wastewater is rare so far in china, the experimental results obtained in this paper provide references for further research and utilization.