Advanced oxidation and artificial recharge: a synergistic hybrid system for removal of organic micropollutants.

Dunea, the drinking water company for The Hague and surroundings, has as objective the production of drinking water of impeccable quality, particularly with respect to organic micropollutants. As organic micropollutants are only a minor part of the total natural organic matter, a challenge is posed in targeting the removal of a very small, specific part of the DOC, without removing all of the natural organic matter. In addition, organic micropollutants encompass a broad range of physicochemical properties, which make their removal by a single treatment step impossible. Combining AOP with artificial recharge and recovery, two complementary processes are expected to provide a hybrid system for organic micropollutant removal, according to the Dutch multiple barrier approach. Pilot-scale experiments with O3 and different advanced oxidation processes (UV/H2O2, UV/O3 and O3/H2O2) were carried out in cooperation between Dunea and ITT Wedeco. The pilot installation had a capacity of about 0.5–2.0 m3/h, with a varying LP-UV-dose, ozone dose and peroxide dose. Atrazine, isoproturone, carbamazepine, diclofenac and ibuprofen are well removed by UV/H2O2 as well as by O3/H2O2. In general, O3/H2O2 is a more energy efficient process compared to UV/H2O2. MTBE is best removed by O3/H2O2, Amidotrizoic acid and iohexol are best removed by UV/H2O2.