Application of UV and UV/H2O2 to seawater: Disinfection and natural organic matter removal

Application of new disinfection technologies for marine waters has been investigated recently, mainly ozone and UV. This study proposes to compare UV performances to an AOP, UV/H2O2, for seawater disinfection and natural organic matter removal. Those processes present the interest in avoiding the formation of disinfection by-products such as bromate and trihalomethanes. For the doses applied, UV and UV/H2O2 achieved full disinfection. Organic matter degradation was greatly improved by H2O2 addition achieving absorbance reduction and biodegradability increase. Mineralization was very poor (less than 10%). Oxidant efficiency decreases with the increase of hydrogen peroxide consumption. Bromide oxidation by-products were not observed. No residual oxidant, no bromate and no disinfection by-products were formed. Those observations are consistent with the theory and suggest a real interest of UV/H2O2 for seawater treatment in specific areas where organic matter degradation has to deal with the control of toxic by-products generation (marine aquaculture, aquarium).

► Seawater disinfection is obtained by UV and UV/H2O2 treatment.
► Low mineralization is obtained for both processes.
► Aromatic organic matter is oxidized into biodegradable compounds.
► No disinfection by-product are formed, nor bromate, nor residual oxidant.