An overall COD removal of 87% from the settled greywater was
achieved with 3 h of UVC/10mM H2O2 treatment (residual
COD¼ 30 mg l1). Most of the organic compounds were
removed by oxidation since only 13% COD was removed by
settlement. When the destruction of organic contaminants is
required, such as for xenobiotic compounds of unknown
toxicity, biodegradability and bioaccumulation characteristics,
the use of UVC/H2O2 would be advantageous. One
possible configuration would include settlement of the greywater
to remove lint, hair and large particles prior to UVC/
H2O2 treatment and subsequent disinfection; for highly turbid
greywater, removal of suspended solids would be required.