Study On Advanced Treatment Technology Of Ozonization Enhanced Coagulation For Secondary Effluent From The Municipal Wasterwater Plant

Based on the problem of conventional coagulation advanced treatment process, Advanced treatment of the secondary effluent from the wastewater treatment plant by the ozone enhanced coagulation treatment technology (OECT)was studied in this research。The enhanced coagulation effect of ozone in OECT was investigated the pollutant removed efficiency by OECT and by traditional coagulation process. Furthermore, continuous-flow experiment of the combination of OECT and variable-void deep filter was conducted to verify that ozone could improve the refractory compound and soluble pollutant removed rate in the traditional coagulation process. And the sunitability of OECT was studied the advanced treatment effect of OECT on various secondary effluent from other wastewater treatment plant.The results show that:(1) Secondary effluent treatment efficiency by OECT was better than that by the traditional coagulation treatment, when there exist ozone, the optimal PAC concentration was 8mg/L. After treated by flouculation CODCr, UV254, turbidity, color and TP were 20.77%, 19.13%, 58.78%, 30.30% and 28.4%, respectively. With ozone concentration of 1.5mg/L and PAC concentration of 6mg/L, and the reaction time was 15min, after treated by the ozone-enhanced coagulation effluent CODCr, UV254, color removal rate were 41.98%, 58.7%, 47.1%, which increased by 21.21%, 39.57%, 16.8% than the simple removal rate of pollutants by the coagulation treatment.(2) Ozonation can improve the removal efficiency of organic matter in raw water with combining micro-flocculation filter with variable-void deep filter technology. When the ozone dosage was 1.5mg/L, PAC dosage was 4mg/L, coagulation 15min, system operation period of 16h, the turbidity, CODCr, UV254, TP and color removal efficiency were 79.0%, 46.5%, 56.6%, 30.8% and 69.2%, respectively, increased by 6.7%,16.8%,48.4%,9.1% and 37.3% compared with the traditional combining micro flocculation filter with variable-void deep filter technology.(3) The study on ozonation enhanced coagulation treatment of Haibo River waste water plants in Qingdao and the waste water plants in Jining City showed that: Ozonation enhanced coagulation of traditional coagulation process has a positive impact. For the treatedment of secondary effluent from Haibo River waste water plants in Qingdao,the removing rate of CODCr, UV254, color, TP by effluent ozone enhanced coagulation treatment, were 70.2%, 58.8%, 54.1%, 60.9%, 55.4%, respectively, increased 8.7%, 21.7%, 35.1%, 37.3%, 20.6% compared with conventional coagulation;for the secondary treated effluent from the waste water plants in Jining City,the removing rate of CODCr, UV254, color, TP with effluent ozone enhanced coagulation treatment,were 70.1%, 36.2%, 35.9%, 60.9%, 69.0%, respectively, respectively, compared with conventional coagulation increased 17.2%, 20.9%, 20.6%, 39.4% , 26.2%.(4) Ozonation enhanced coagulation is obviously superior to traditional coagulation on the treatment of the removal refractory organics and colour from WWTP. And ozonation could improve the removal rate of turbidity and TP of the secondary effluent in a certain range.In conclusion,ozonation could promote the coagulation treatment effect and improve the sewage treatment efficiency. This study could provide new ideas for advanced sewage treatment .