Improving UV/H2O2 performance following tertiary treatment of municipal wastewaterElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ew00233a

• Main Authors: Ulliman, Sydney L, Miklos, David B, Hübner, Uwe, Drewes, Jörg E, Linden, Karl G
• Format: Article
• Language: English
• ISSN: 2053-1400; 2053-1419
• DOI: 10.1039/c8ew00233a

The ability of UV/AOP to treat trace organic contaminants (TOrCs) in wastewater is inhibited by (1) UV light-absorbing species and (2) hydroxyl radical (&z.rad;OH) scavenging species. We address these challenges by investigating four diverse technologies, single-stage biofiltration, sequential biofiltration, coagulation-flocculation-sedimentation-filtration (CFSF), and nanofiltration, as options for improving water quality conditions just prior to UV treatment, with and without added hydrogen peroxide (H 2 O 2 ). By evaluating UV 254 transmittance (UVT), &z.rad;OH scavengers, and &z.rad;OH steady-state concentrations, we found nanofiltration treatment to produce the most favorable pre-UV and UV/H 2 O 2 water quality conditions. In comparing CFSF, single-stage biofiltration and sequential biofiltration treatment, CFSF treatment resulted in the highest increase in UVT and all three technologies reduced the scavenging capacity by ∼24% despite differences in removal of typical &z.rad;OH scavengers. UV and UV/H 2 O 2 performance were evaluated by tracking the degradation rates of 11 targeted TOrCs for each pre-UV/H 2 O 2 treatment scenario. Applying the additional treatment, average pseudo first-order degradation rates of TOrCs under UV/H 2 O 2 increased by 20 to 92%, informing potential strategies to increase the oxidation potential of UV/AOP systems applied to wastewater. The ability of UV/AOP to treat trace organic contaminants (TOrCs) in wastewater is inhibited by (1) UV light-absorbing species and (2) hydroxyl radical (&z.rad;OH) scavenging species.