Performance of different advanced oxidation processes for tertiary wastewater treatment to remove the pesticide acetamiprid

BACKGROUND: This work studied the performance of different advanced oxidation processes (AOPs) as tertiary treatment for removal of the pesticide acetamiprid from water. Specifically, UV, UV/TiO2, UV/H2O2/Fe, and two systems with persulfate (PS), UV/PS and UV/PS/Fe, were evaluated. RESULTS: The study was carried out in deionised water, synthetic water from a secondary effluent and real effluent from a conventional activated sludge effluent (CAS effluent). In addition, the effect of humic acids, lignin-derivative and lauryl sulphate was investigated as organic matter that affects AOP efficiency. CONCLUSIONS: Photo-Fenton at natural pH proved to be the most efficient process in all matrices. The persulfate systems have also shown that they have great potential for micropollutant removal. It was found that humic acids reduced degradation efficiency for UV/H2O2/Fe and UV/PS/Fe due to competition with radicals. Humic acids had a negative impact on UV photolysis at high concentration due to the absorptivity of UV light. Lignin had a negative effect on AOPs that used iron, forming Fe(II)-complexes with high absorptivity which act as a light filter. For lauryl sulphate, its chemical structure did not favour the formation of iron complexes at natural pH, resulting in similar degradation rates for UV/H2O2/Fe, UV/H2O2, UV/PS and UV/PS/Fe. (C) 2014 Society of Chemical Industry