Simultaneous removal of tetracycline and disinfection by a flow-through electro-peroxone process for reclamation from municipal secondary effluent.

Pharmaceutical and personal care products as one of the micropollutants and bacteria in secondary effluent restrict the water reuse from municipal secondary effluent. Electro-peroxone (EP) process where HO is generated in-situ by electrolysis is an emerging advanced oxidation process and an improvement of traditional peroxone method (O/HO). In this work, a flow-through EP process was compared with ozonation and electrolysis for simultaneous disinfection and degradation of tetracycline (TC). The disinfection effect by EP was higher than the sum of standalone ozone and electrolysis and the coupling coefficient of ozonation and electrolysis in EP process was 1.2. The flow-through EP system presented similar efficiency for separately and simultaneously treating E. coli and TC. For the actual secondary effluent treatment, trihalomethanes, haloacetonitrile and halonitromethanes, the main disinfection by-products, were much lower than the WHO's thresholds for drinking water. TOC and COD removal was 44% and 65%, respectively, at flow rate of 35 mL/min. BOD, bacteria, pH and other parameters in the effluent could satisfy the recreational landscape water quality standard, and the required energy consumption was 0.47 kW h/m at the flow rate 35 mL/min. Most of the degradation products were small-molecule organic acids, and possible degradation pathway of TC was suggested.