Raw and treated DWW were routinely
sampled every 2 to 3 weeks for over 1 year and
analysed for chemical and microbiological parameters including: pH, electrical conductivity, 5-d
biological oxygen demand (BOD5
); chemical
oxygen demand (COD), total suspended solids
(TSS), total nitrogen (TN) by persulphate digestion followed by UV analysis, nitrite, ammonia
using the Nessler method [12], nitrate by second
derivative [13] and E. coliby either spread plate
or membrane filtration methods using TBX agar
(Merck, Germany). Analyses were performed
following standard methods [14] unless specified
otherwise.