The Test Research Of Coking-Plant Wastewater Advanced Treatment By BAF

The components are very complex in coking-plant wastewater,in which contains refractory organic compounds such as tar,benzene,phenol,cyanide,quinoline and pyridine etc,and great changes usually happen to water quality and water flow.It is a typical industrial wastewater,in which contains a number of toxic and nocuous compounds.But most of the traditional treatment processes were conventional activated sludge method,through which the removal of COD_crand ammonia nitrogen is not favorable and the effluent concentration couldn't attain the wastewater drainage level,which will cause severe harm to our environment and human body.On the traditional foundation of the scorch factory,therefore,it is necessary to increase a reasonable depth handling to make useless water attain the wastewater drainage level,which is a kind of economic technology.Research shows that it is feasible that biological aerated filter is used to be the supplement of the scorch useless water of target hitting because of its advantages.According to the refractory character of coking-plant wastewater,the experiment disscusses the possibility that the oxidizing agent(H₂O₂)and domestic wastewater improve the degrading capability of coking-plant wastewater and the effects of the dosage of H₂O₂ to coking-plant wastewater advanced treatment by BAF and inspects the effects of gas-water ratio and reflux ratio to coking-plant wastewater advanced treatment.The results show that Oxidant hydrogen peroxide used for additional ways to improve the standards of the coke plant wastewater biodegradability is practicable and the optimal H₂O₂/COD_cr,gas-water ratio and reflux ratio are 3:1,2～3:1,0.5:1 respectively in the test of coking-plant wastewater advanced treatment by BAF.Under the optimal condition,that is to say,the results are the best when H₂O₂/COD_cr,gas-water ratio,reflux ratio are 3:1,2～3:1,0.5:1 respectively,then the average removal rate of COD_cr,ammonina nitrogen comes up to 49.35%, 91.32%respectively and the system is stable and reliable.According to the experiment of bed material height,The concentration of CODer in the effluent by different filter height in hypoxia reactor of BAF and the concentration of ammonia nitrogen in the effluent by different filter height in aerobic reactor of BAF both exist a regular,the regulars are[COD_cr]= 230.97e(-0.0042x),[NH₃-N]=5E-05x³-0.0063x²-0.0041x+20.565 respectively; Furthermore,there is an optimal relationship between the aerobic bed material height and the hypoxia bed material height,and the two is the optimal ratio of the aerobic bed material height to the hypoxia bed material height,then the syetem is the best.On the basis of the back-washing experiment,the removal capacity of COD_crand ammonia nitrogen needs some time to recover after the back-washing,and the time are 8h,10h respectively;the regular of recovery are [COD_cr]=-0.2558x²+7.4086x,[NH₃-N]=-0.4337x²+12.697x respectively.In this research,Not have to feeding carbon and alkali,the water quality of effluent from the system of BAF could meet the secondary national standard about wastewater discharge(GB8978-1996).The concentration of COD_crand ammonia nitrogen was less than 150mg/L and 25mg/L each.This craft is economic and feasible in technology.