Advanced removal of organic micro pollutants and microbial load from aqueous systems by sonolysis coupled with classical AOPs processes

Abstract

Research activity of the project led to selection of some flow treatment phases for drinking water surface sources which contain ultrasound application for removal of natural organic matter, trihalomethanes generated in the chlorination phase, ammonia ions, sulphides and manganese and for diminishing of chlorine amount using ultrasound for partial disinfection. The correlation of experimental results prove that is possible advanced removal of natural organic matter (NOM) – 60 – 90% by sonolysis with iron catalyst and of specific organic matter (THMs) – 95% by hybrid sonolysis US/H2O2/UV. Disinfection tests of drinking water by direct sonolysis show the diminishing of mesophilic bacteria content with one order and inactivation efficiency was 96%. In case of inorganic micropollutants (ammonia, sulphides, manganese) coupling of sonolysis with chlorination (to small chlorine doses - stoichiometric amount) led to ammonia removal with 60 – 70% efficiency and experimental tests of hybrid sonolysis US + H2O2 (stoichiometric dose of peroxide) for sulphides removal from drinking water (≤ 10 mg S2-/l) demonstrated the possibility to remove them with 75% efficiency for 30 minutes reaction time. Maximum removal efficiency of manganese from water was 65% in case of hybrid treatment system (US +H2O2 + Fe). These results of laboratory scale show that sonolysis can be effectively integrated in the classical treatment flows of drinking water after adaptation to specific quality conditions of water source and to present treatment flow