An investigation into reservoir NOM reduction by UV photolysis and advanced oxidation processes

A comparison of four treatment technologies for reduction of natural organic matter (NOM) in a reservoir water was made. The work presented here is a laboratory based evaluation of NOM treatment by UV-C photolysis, UV/H2O2, Fenton’s reagent (FR) and photo-Fenton’s reagent (PFR). The work investigated ways of reducing the organic load on water treatment works (WTWs) with a view to treating ‘in-reservoir’ or ‘in-pipe’ before the water reaches the WTW. The efficiency of each process in terms of NOM removal was determined by measuring UV absorbance at 254 nm (UV254) and dissolved organic carbon (DOC). In terms of DOC reduction PFR was the most effective (88% removal after 1 min) however there were interferences when measuring UV254 which was reduced to a lesser extent (31% after 1 min). In the literature, pH 3 is reported to be the optimal pH for oxidation with FR but here the reduction of UV254 and DOC was found to be insensitive to pH in the range 3–7. The treatment that was identified as the most effective in terms of NOM reduction and cost effectiveness was PFR.