Study On The Treatment Of Oily Wastewater From Cold Rolling Mill With The Process Of EGSB And Biological Contact Oxidation

The exploration of a rational and effective method used to treat oily wastewater from cold rolling mill was focused on in this paper. Referred to its characteristics, present method of the treatment and existed research, process of coagulation, EGSB and biological contact oxidation was put forward to treat oily wastewater from cold rolling mill of WISCO and resolve the problem that the effluent of oily wastewater couldn't reach the Standard stably. The research primary discussed the treatment of the effluent of oily wastewater after coagulation by the process of EGSB and biological contact oxidation. Experimental studies have shown that as follow,(1) The startup of the EGSB reactor with oily wastewater treated form cold rolling mill was operated efficiently for 25days at normal temperature with low influent concentration, low organic loading and high hydraulic retention time. After 40days, the organic load reached 4.27kgCOD/(m3?d), COD and oil removal efficiency reached 96.13% and 69.58% respectively, and the granular sludge formed had good setteability and high bioactivity. After 90days, the concentration of COD and oil removal efficiency were stable at 95% and 80% respectively and those of effluent were respectively stable at 150mg/L, 20mg/L below and the biodegradability of the effluent increased.(2) The startup of biological contact oxidation pond was carried out semi-continuously with sludge inoculated. The influent of the pond has been added glucose and other nutrients element of nitrogen and phosphorus according to that COD: N: P was 100:5:1 and the COD of the influent reached 200mg/L almost. After 14days, there was a lot of biofilm formatted. Then it was to make bacterium in the biofilm acclimatized with gradually increased the inflow--the effluent of EGSB reactor, glucose addition reduced. After 27days, the biofilm with stronger shock resistant ability was generated and got a high efficiency of treatment with a stable water quality of the effluent, COD and oil contents of effluent were respectively at 91.48mg/L and 11.02mg/L.(3) When the operation of EGSB-biological contact oxidation joint process was stable, the optimum operated conditions with oily wastewater form cold rolling mill treated was as following, the inflow and the back flow of EGSB reactor was respectively 5L/h and 20L/h, the hydraulic retention time of EGSB and biological contact oxidation pond were respectively 12hours and 1.5days and the COD, oil of effluent water were removed all above 97%, effluent water comes up to Integrated Wastewater Discharge Standard (GB/T 8978-1996). Therefore, a scientific technology route was provided for engineering application and has broad prospects.