Development and scale-up of vacuum UV-based advanced oxidation to degrade aqueous organic micropollutants

ENG- The degradation of organic micropollutants is crucial for the realization of sustainable (re)use of water. Advanced oxidation processes (AOP) are often chosen for this purpose. One such widely applied AOP is UV/H2O2 AOP, which employs either medium-pressure or low-pressure mercury (LP-Hg) lamps. LP-Hg lamps have two peak wavelengths, at 253.7 nm and 184.9 nm. The 184.9 nm (or Vacuum UV (VUV)) can photolyse water to produce hydroxyl radical (HO.) amongst other reactive radicals, thus eliminating the need for the addition of oxidants. However, due to its high absorption by water, 1.76cm-1, VUV is almost completely absorbed in the first 5mm of the water depth, in the case of ultra-pure water. In real water matrices, due to the presence of anions like chloride, sulfate, nitrate, etc., absorption at VUV is higher, resulting in an even smaller penetration depth for the VUV photons. Consequently, the reactive radicals will be concentrated in a small zone around the lamp. This attribute makes it challenging to design photoreactors that employ VUV for AOP purposes. Although several laboratory-scale research were conducted and published on VUV-AOP, their implications on the design of pilot-scale photoreactors were not known. These hurdles impeded the development of VUV-AOP further than the lab scale. To address these challenges in the scope of a doctoral thesis several companies and research institutes collaborated. The companies involved were PWN (drinking water utility), the Netherlands; Trojan UV (municipal UV system and AOP system manufacturer and supplier); Canada, Brown and Caldwell (full-service environmental engineering and consultancy firm), the USA and the research institutes involved were Wetsus (centre of excellence for sustainable water technology); the Netherlands and the Catalan Institute for Water Research (ICRA), Spain. The experimental work was carried out in Wetsus and PWNT (previously commercial daughter company of PWN) in the Netherlands. This doctoral thesis explores the feasibility of pilot-scale stand-alone chemical-free VUV-AOP alongside the benefits of a combined VUV+ UV/H2O2 AOP