2.4. Experimental procedure
The greywater was settled overnight to simulate the effect of
a storage facility in which hair, lint and large particles are
settled. When necessary, the pH of the settled greywater was
adjusted (1 M H2SO4 or 1 M NaOH) before the UVC/H2O2
treatment. After irradiation, catalase (5300 U ml1) from
Aspergillus niger (Calbiochem) in phosphate buffer (33 mM
Na2HPO4 and 16.8 mM KH2PO4, pH 7) was used to decompose the residual H2O2 to less than 2 mg l1 (indicated by Merckoquant
peroxide test strips (Merck)) before the sample was
analysed. The COD contribution from the catalase was
determined as 1.5 mg l1 and all results were corrected
accordingly.