Research And Application Of Ozone Electrocatalytic Oxidation Process For Treatment Of Reverse Osmosis High Salt Concentrated Water

In recent years,with the development of social development and environmental awareness,people not only pay attention to the discharge of wastewater,but also require enterprises to reuse wastewater to the maximum extent and reduce environmental pollution.The refractory organic matter in the reverse osmosis drained water with high salinity in coal chemical industry is not conducive to the subsequent salt crystallization and quality recovery,which seriously affects the operation of enterprise projects.The COD of reverse osmosis high salt concentrated water in this subject is 750?800 mg/L,the conductivity is 27.0^28.0 mS/cm,and the pH value is 7.0?7.5.According to the requirements of enterprises,the COD removal rate of high salt concentrated water after treatment More than 60%,the energy consumption per ton of water is less than 10 kW h.By studying the ozone electrocatalytic oxidation process,it meets the requirements of enterprises for the treatment of reverse osmosis high-salt concentrated water,and also provides a reference for the treatment of another similar wastewater.Ozone oxidation method and electrocatalytic oxidation method were used to carry out bench-scale experimental treatments on reverse osmosis drained water with high salinity from a coal chemical coking plant.By comparing the COD(chemical oxygen demand)removal rate,pH,CON(conductivity)of wastewater,the energy consumption per unit ton of water and the change of COD energy consumption per kilogram were optimized by single factor experiments.The optimal combination of ozone oxidation and electrocatalytic oxidation was determined as ozone and electrocatalytic oxidation in a series manner.The optimal parameters determined by ozone-electrocatalytic oxidation method are:reaction time 60 min(ozone reaction 30 min,electrocatalytic reaction 30 min),ozone flow rate 0.1 L/min,ozone concentration 32.0 mg/L,the anode material is a Ru-Ir oxide electrode,the cathode material is a titanium electrode,the current density is 5 mA/cm2,and the electrode spacing is 1 cm.After the wastewater was treated by the ozone-electrocatalytic oxidation process,the final COD removal rate was 67.6%.The energy consumption per unit ton of water treated by ozone-electrocatalytic oxidation treatment is 6.4 kW h/m3,and the corresponding unit of kilogram COD treatment energy consumption is 16.1 kW h/m3.According to the parameters optimized by the pilot test,the pilot process was designed,"raw bucket-ozone oxidation reactor-intermediate bucket-electrocatalytic reactor-outlet bucket" and electrocatalytic reactor and ozone reactor.The wastewater is treated by ozone-electrocatalytic oxidation.The pilot water inflow is a secondary reverse osmosis high-salt concentrated water in a zero-discharge workshop of coking wastewater in a factory with a COD of 750.0 mg/L,a conductivity of 24.7 mS/cm,a pH of 7.5,and a treatment scale of 2.4 m3/d.The continuous operation of the reactor for 9 h,the final COD removal rate was 68.6%,the ozone-electrocatalytic oxidation treatment corresponding to the energy consumption per unit ton of water was 7.9 kW h,and the energy consumption per kilogram of COD treatment was 18.5 kW h.Therefore,meeting the requirements of the company has certain economic and technical feasibility.