Experimental Study On Advanced Treatment For Oily Wastewater By Ozone-Biological Aerated Zeolite Processes

The pollutants of petroleum hydrocarbons into water had a great impact on aquatic organisms, the surrounding environment and natural landscape. For low concentration of oily wastewater, especially for the surface water polluted by petroleum hydrocarbons, the treatment process has caused a great concern. Although the content of petroleum hydrocarbons in water was small, the hardness was serious. The depth treatment of river polluted by petroleum hydrocarbons was introduced in this paper.The index of water quality in this study included three factors: content of oil, chemical oxygen demand(COD) and ammonia nitrogen. In this paper, the removal efficiency of ozone pre-oxidation under different ozone dosage and different contact time was researched through static test. And the results determined was that the best ozone dosage of 8mg/L, the contact time of 10min.The zeolite with advantages of high surface area, high adsorption and ion change properties was used as filter media in biological aerated zeolite. In this experiment, the start of biological membrance was introduced in biological aerated zeolite, and the impact of operating condition on the effect of oily wastewater treatment and the performance of enduring fluctuation of pollution was researched. The best operating condition of biological aerated filter process was also determined. And the conditions contained pH = 6.5 ~ 7.5, the temperature of 20 ~ 250C, the hydraulic load of 1.1205m/h, the hydraulic retented time(HRT) of 1.766h, the aeration capacity of 30ml/minand the gas-water ratio be 10:1. The biofilter under this condition had a high removal efficiency of pollutants and low operating cost.The effluent quality was improved using the process of ozonation and biological aerated zeolite in series at the best running condition. Condition of enter water:COD:35mg/L; ammonia nitrogen:2.0mg/L; oil:3.0mg/L.The content of oil in effluent was stabilized at 0.15mg/L, and COD at 11mg/L around. And the removal of ammonia nitrogen was close to 100%. COD and ammonia nitrogen of effluent reached to the classâ… of surface water environmental standard water, and content of oil to the classâ…£. The process of ozonation-biological aerated zeolite of oily wastewater treatment is feasible in technic.