Efficiency and energy requirements for the transformation of organic micropollutants by ozone, O3/H2O2 and UV/H2O2

• Published in: Water research (Oxford) Vol. 45; no. 13; pp. 3811 - 3822
• Main Authors: KATSOYIANNIS, Ioannis A, CANONICA, Silvio, VON GUNTEN, Urs
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier 01.07.2011
• Subjects: Applied sciences; Atrazine - chemistry; Chlorobenzoates - chemistry; Dimethylnitrosamine - chemistry; Exact sciences and technology; Hydrogen Peroxide - chemistry; Kinetics; Oxidation-Reduction; Ozone - chemistry; Pollution; Sulfamethoxazole - chemistry; Ultraviolet Rays; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - chemistry; Water Purification - methods; Water treatment and pollution; Energy consumption; Organic matter; Hydrogen peroxide; H; Ozonation; Waste water; O; Ozonization; Dissolved organic matter; Energy; Hydroxyl radicals; Micropollutant; Oxidation; Organic compounds; Photochemical degradation; Photochemical oxidants; Micropollutants; Pollutant behavior; Scavenging; Ozone; Scavenging rate; Ultraviolet radiation; Surface water; Lakes; Kinetics; UV/H
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2011.04.038

The energy consumptions of conventional ozonation and the AOPs O(3)/H(2)O(2) and UV/H(2)O(2) for transformation of organic micropollutants, namely atrazine (ATR), sulfamethoxazole (SMX) and N-nitrosodimethylamine (NDMA) were compared. Three lake waters and a wastewater were assessed. With p-chlorobenzoic acid (pCBA) as a hydroxyl radical ((•)OH) probe compound, we experimentally determined the rate constants of organic matter of the selected waters for their reaction with (•)OH (k(OH,DOM)), which varied from 2.0 × 10(4) to 3.5 × 10(4) L mgC(-1) s(-1). Based on these data we calculated (•)OH scavenging rates of the various water matrices, which were in the range 6.1-20 × 10(4) s(-1). The varying scavenging rates influenced the required oxidant dose for the same degree of micropollutant transformation. In ozonation, for 90% pCBA transformation in the water with the lowest scavenging rate (lake Zürich water) the required O(3) dose was roughly 2.3 mg/L, and in the water with the highest scavenging rate (Dübendorf wastewater) it was 13.2 mg/L, corresponding to an energy consumption of 0.035 and 0.2 kWh/m(3), respectively. The use of O(3)/H(2)O(2) increased the rate of micropollutant transformation and reduced bromate formation by 70%, but the H(2)O(2) production increased the energy requirements by 20-25%. UV/H(2)O(2) efficiently oxidized all examined micropollutants but energy requirements were substantially higher (For 90% pCBA conversion in lake Zürich water, 0.17-0.75 kWh/m(3) were required, depending on the optical path length). Energy requirements between ozonation and UV/H(2)O(2) were similar only in the case of NDMA, a compound that reacts slowly with ozone and (•)OH but is transformed efficiently by direct photolysis.