Study On The Control Technology Of Coking Wastewater Biochemical Treatment Sludge Disintegration

Coking wastewater was industrial wastewater with highconcentration of organic pollutants and some toxic contaminants including phenol,cyanide, ammonia, sulfide, sulfur cyanide, benzene and polycyclic aromatic hydrocarbonswhich was generated in the refining progress of coke, coal gas purification and productrecovery. It is one of the intractable wastewater in the metallurgical industry because ofcomplex composition and poor biodegradability. It was generally considered that activatedsludge process has comparable good effect on purifying organic wastewater. And it is alsoequally applicable in the treatment of coking wastewater industry. The activated sludgeprocess is not suited to the sudden change of water quality as well as environment. Therewill be unusual circumstances such as sludge disintegration, resulting in sludge wastage,reduced sewage treatment effect and deterioration of water quality.Activated sludge of coking wastewater was investigated by cultivation andacclimatization in laboratory and trial field. Factors of sludge disintegration, biofaciesbefore sludge disintegration conditions of sludge disintegration and biofacies change wasalso studied. The reasons for sludge disintegration mechanism were analyzed in order tofind the sludge disintegration control methods.Influencing factors in the process of sludge disintegration was investigated. Theresults show that sludge disintegration will occur when concentration of CODc_r>4000mg/l, NH₃-N>380mg/l, the pH>9or pH<5.5, the system temperature greater than40℃or less than10℃, volatile phenol concentrations greater than600mg/l cyanideconcentration greater than50mg/l. So in the biological progress of coking wastewater,appropriate parameters of sludge disintegration is that influent concentration ofCODc_r<4000mg/l, NH₃-N <380mg/l, aerobic biological system pH value remained atabout7.5, the system temperature control at about35℃, the concentration of volatilephenols between400to600mg/l, cyanide concentration of less than50mg/l in order toensure the efficient and stable degradation of pollutants.