Study On The Oxidation Degradation Of Phenol Wastewater By O₃-UV-US Synergistic Action

Water pollution is a problem faced by the international society.With the rapid development of China’s industrial economy,more and more toxic organic waste compounds has produced,The damage to humans and the aquatic environment is becoming more and more big.Phenol is an important chemical raw materials in China’s industrial production and the production process by-products,it is a toxic substance,are toxic to the human body and environment,unable to degrade in the natural state of their own.AOPs（Advanced oxidation Process）can effectively degrade toxic and harmful organic matter of the wastewater,it uses the oxidation process produces ·OH oxidative degradation of organic to carbon dioxide and water.Ultrasonic oxidation technology is a new type Advanced oxidation Process that begin to study in the recent ten years,also has a good application prospect.In this paper,we put O₃,UV,US three oxidation technical synergy,use the mechanism of the cavitation effect by ultrasonic and disinfection by ultraviolet light can stimulate the ozone produced more ·OH,research the factors of degradation simulation phenol wastewater by O₃-UV,O₃-US,O₃-UV-US,and the cost analysis of the best reaction time and the health risk assessment of the best degradation effect.The experimental results show that the effect of oxidation degradation by single UV,and single US are not ideal,the method of O₃-UV-US synergy oxidation is much better than single O₃,O₃-UV,O₃-US.The best conditions of O₃-UV oxidation degradation of phenol wastewater is the initial pH of 6,O₃ inflow is 0.8mL/min,the initial concentration is 140mg/L.Under the condition and reaction to 4h,phenol removal rate is 82.2%,the COD removal rate is 80.2%,the cost is0.31yuan/kg;The best conditions of O₃-US is the initial pH of 6,O₃ inflow is 0.8mL/min,phenol initial concentration is 140mg/L,UV frequency is 34 kHz,power is 200 W.Under the condition and reaction to 4h,the phenol removal rate is 80.5%,the COD removal rate is78.1%,the cost is 0.32yuan/kg.The best conditions of O₃-UV-US synergy oxidation degradation of phenol wastewater is the initial pH of 8,O₃ inflow is 0.6mL/min,phenol initial concentration of 140mg/L,US frequency is 34 kHz,power is 300 W.Under the condition,the reaction to 4h,phenol removal rate 94.3%,COD removal rate is 92.1%,the cost is0.33yuan/kg.Considering treatment effect and costs,O₃-UV-US synergy is the best way of oxidation degradation.Under the best conditions,the health risk assessment results show that after O₃-UV-US synergy oxidation degradation,the health risk value of phenol is lower than the value of the limit concentration（C1）which may cause chronic toxicity to fresh aquatic life and the limit concentration（C2）which may cause hazards to humans,it means R（0.002×10-6a-1）<R1（0.003×10-6a-1）<R2（0.004×10-6a-1）,and this will not cause danger to aquatic organismsand human body.