A Novel Flow-through Electro-peroxone Process For Disinfection And Emerging Organic Contaminants Removal

A flow-through electro-peroxone system?E-peroxone?fulfilled the efficient generation·OH by the reaction of ozone with H₂O₂ produced in-situ.The system showed one order of magnitude higher inactivation of Escherichia coli?E.coli?than ozonation and electrolysis in the treatment of simulated ballast water and simultaneous disinfection and degradation of tetracycline.Several experimental factors were optimized,such as aeration rate,current and flow rate.In the disinfection of the simulated ballast water,the concentration of hydroxyl radical and free chlorine was measured to be 14.7?M and 3.2 mg/L at the current of50 mA,aeration rate of 50 mL/min and flow rate of 7 mL/min.Ozone was the major disinfectant,followed by·OH.Free chlorine did not play a main role in the disinfection in the E-peroxone process.The inactivation efficiency log?c/c₀?reached-5.5 when the initial concentration of E.coli was 10⁶-10⁷ CFU/mL in the influent and the disinfection effect could last for five days.At initial E.coli of 0.6×10⁴ CFU/mL,the effluent could meet the D-2 standard proposed by International Maritime Organization?IMO?.Furthermore,the energy consumption of the E-peroxone system for treating these two solutions was 0.041 and 0.089 kWh/m³,respectively.Moreover,the trihalomethanes?THMs?,one of disinfection by-products?DBPs?in the effluent,could meet the WHO's?World Health Organization?drinking water standard.In the study of simultaneous disinfection and degradation of tetracycline,the ozone and electrolysis in the E-peroxone process had a certain coupling effect in terms of disinfection.The efficiency of the hybrid system increased by 1.2 times than the sum of ozonation and electrolysis efficiency alone.The amount of aeration affects the production of hydroxyl radicals.In Na₂SO₄ solution,when aeration rate was 20,50,80,and 110 mL/min,the·OH yield was 11.2,21.0,33.1,and 47.4?M,respectively.In addition,there was almost no difference in the effects of the E-peroxone process for the degradation of the tetracycline,sterilization and simultaneous sterilization and degradation of tetracycline,i.e.,under the same energy consumption,the oxidant in the E-peroxone system was sufficiently utilized,and therefore the amount of contaminants removal was increased.The secondary effluent treated by the E-peroxone process could meet the landscape reuse water standards.Moreover,the concentration of THMs,TCNM,and HANs,as three representative disinfection by-products,was very low and they could be safely discharged.Therefore,the flow-through E-peroxone system was cost-effective and promising for the disinfection of simulated ballast water and the advanced treatment of the actual secondary effluent.