Greywater treatment by UVC/H2O2.
Greywater treatment by UVC/H(2)O(2) was investigated with regard to the removal of chemical oxygen demand (COD). A COD reduction from 225 to 30 mgl(-1) (overall removal of 87%) was achieved after settling overnight and subsequent irradiation for 3h with 10mM H(2)O(2). Most of the contaminants were removed by oxidation since only 13% COD was removed by settlement. The removal of COD in the greywater followed a second-order kinetic equation, r=0.0637[COD][H(2)O(2)], up to 10mM H(2)O(2). A slightly enhanced COD removal was observed at the initial pH of 10 compared with pH 3 and 7. This was attributed to the dissociation of H(2)O(2) to O(2)H(-). The treatment was not affected by total concentration of carbonate (c(T)) of at least 3 mM, above which operation between pH 3 and 5 was essential. The initial biodegradability of the settled greywater (as BOD(5):COD) was 0.22. After 2h UVC/H(2)O(2) treatment, a higher proportion of the residual contaminants was biodegradable (BOD(5):COD=0.41) which indicated its potential as a pre-treatment for a biological process.
Chin
W H
WH
School of Civil, Environmental, and Chemical Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001, Australia.
Roddick
F A
FA
Harris
J L
JL
D000838:Anions / Q000032:analysis; D001639:Bicarbonates / Q000032:analysis; D002254:Carbonates / Q000032:analysis; D002712:Chlorides / Q000032:analysis; D006861:Hydrogen Peroxide / Q000032:analysis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010100:Oxygen / Q000032:analysis; D055668:Photochemical Processes; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*; D014873:Water Pollutants / Q000032:analysis
D000838:Anions; D001639:Bicarbonates; D002254:Carbonates; D002712:Chlorides; D014873:Water Pollutants; D006861:Hydrogen Peroxide; D010100:Oxygen