Application Research Of Electrocoagulation-biochemical Combination Process For Treating Coal Gasifier Wastewater

Coal gasification wastewater contains high concentrations of phenol and phenolic variety,composition is complex,belongs to a high concentration of refractory organic wastewater.Coal gasifier treatment of wastewater containing phenol,has always been a big problem in the field of wastewater treatment at home and abroad.In this paper,I want to deal with waste gas based on the combination electric flocculation-biochemical process,and to have an optimization design on the parameters of the electric flocculation-biochemical process parameters.First we can remove volatile phenol contaminants using the electric flocculation pretreatment,after improving biodegradability we can use the two-stage biochemical treatment-GESB+A/O to further degrade the organic pollutants in wastewater and CODcr.In this article,I studied on the influence factors about electrical flocculation technology by the orthogonal experiment,the results show that various factors in the process of electrolytic flocculation treatment effect are as follows:current density>reaction time>PH>water plate spacing,the optimum technology conditions are as follows:the current is 9 ma/cm2,the reaction time is 45 min,water is PH = 9,plate spacing is 30 mm.The removal rate of CODcr about electric flocculationis is 84.8?87.5%,the removal rate of volatile phenol is 93.8?96.4%,ammonia nitrogen removal rate is 48.6%,BOD/CODcr increased from 0.21 to 0.36 before processing,it effectively improves the biodegradability of wastewater.In this article,I optimized about he biochemical composition operation parameters,if the low temperature process of EGSB is PH 7.2,the rising velocity is 5 m/h and hydraulic retention time is 2 h,it will be the best for CODcr removal effect.EGSB process index for water:CODcr is 238?346.7 mg/L,the highest removal rate is 86.7%;Volatile phenol is 3.8?6.4 mg/L,removal rate is up to 97.3%.The processing of A/O unit dissolved oxygen is as follows:A stage is 0.2 mg/L,O stage is DO = 2.5 mg/L,the return sludge ratio controls in 70%,PH value in 8.0,A/O process index for water:CODcr is 51.3?57.3 mg/L,removal rate is over 78%.Volatile phenol is 0.26?0.45 mg/L,removal rate is 93%;Ammonia nitrogen is 7.9?8.6 mg/L,removal rate is over 95.2%.The wastewater in generation rate of coal gas makes the water quality become CODcr33.5?51.8 mg/L by electric flocculation,EGSB,A/O biochemistry,medium filtering,the total removal rate is 99.56%;Volatile phenol is 0.26?0.45 mg/L,the total removal rate is 99.9%;Ammonia nitrogen is 7.9?8.6 mg/L,the total removal rate is 96.38%;Suspended matter is 234.7?263.5 mg/L,the total removal rate is 93.19%.The effluent water quality about combination of electric flocculation-biochemical process conforms to the first level of discharge standard requirement in the(GB8978-1996)?standard of sewage comprehensive discharge?.The advantages of the combination are as follows:high processing efficiency,easy equipment and operation,small occupied area,etc.,the investment saves 35%?43%,reducing the sludge in the process is about 40%?60%,the average processing cost saving more than 30%.