Abstract:
The effect of seasonal variations on ultrafiltration (UF) following pretreatment
was investigated in terms of organic removal, removal of fraction, and
molecular weight (MW) distribution. The MW range of effluent organic matter
(EfOM) in biologically treated sewage effluent during winter (BTSE- W) consisted
of large MW. However, the MW ranged from 3000 to 200 daltons in biologically
treated sewage effluent in the summer (BTSE-S). During filtration experiments of
BTSE-S, the UF NTR 7410 filter showed rapid flux decline with time without pretreatment.
FeCI) flocculation removed the hydrophobic (HP) and hydrophilic (HL)
fractions with different trends. In winter the HP fraction was removed up to
68.5%, whereas during the summer season, the HL fraction was removed by up
to 59.8%. Flocculation removed large MW organics together with small MW,
while PAC removed the majority of small MW organics. The flux decline with
adsorption was also more severe than that with flocculation. Considering MW distribution,
when large MW was removed by flocculation, the flux decline was minimized, whereas PAC adsorption which removed small MW still decreased the
permeate flux.
