Municipal Anaerobic Filter Effluent Treatment Using Advanced Oxidation Processes for Unrestricted Crop Production

To meet quality standards for wastewater treatment for reuse, advancement of treatment technologies has been considered very important. One promising avenue is the integration of advanced oxidation processes (AOPs) with Decentralized Wastewater Treatment Systems (DEWATS). This study sought to optimize the efficacy of selected AOPs for polishing the anaerobic filter (AF) effluent of DEWATS as an alternative to the constructed wetlands. Metrics evaluated pathogen reduction efficiency, post-disinfection regrowth, and the treatment effects on the physical parameters (pH, EC, and turbidity), organic matter (sCOD, BOD, DOC, humic), and nutrient concentration (ammonium, nitrates, and ortho-P). Ozonolysis and TiO2 photocatalysis attained a 6.4-log pathogens reduction, whereas UV photolysis recorded a 6-log pathogen reduction. Ozonolysis samples showed no pathogen regrowth, whereas TiO2 photocatalysis registered E. coli and Total coliforms regrowth of 2.5-log and 2.7-log, respectively. UV photolysis registered 0.5-log and 2.2-log regrowth for E. coli and Total coliforms, respectively. TiO2 photocatalysis significantly reduced the BOD, sCOD, humic levels, ortho-P, turbidity, and nitrates while increasing the pH, EC, ammonium, and DOC levels. Ozonolysis significantly lowered BOD, sCOD, humic levels, and turbidity; however, it increased ortho-P, nitrates, pH, EC, ammonium, and DOC levels. UV photolysis resulted in marginal reductions in BOD, nitrates, and turbidity with increased EC, pH, ammonium, DOC, ortho-P, and humic levels. Ozonolysis and UV photolysis insignificantly mineralized the trace elements. TiO2 photocatalysis lowered the concentrations of Al, Fe, Mn, and Zn in the treated effluent. In comparison, ozonolysis was the best AOP, demonstrating a faster effluent treatment rate with no pathogen regrowth.