Water supply networks are generally modelled for a day or longer time period. Under most
circumstances, it is normal to omit the dispersive movement of chlorine and to assume that the
convective transport dominates over dispersion. However, during night time operations the velocities
are signi®cantly decreased. This radical change in the velocity may therefore lead to the following
question: can the available convection based quality models predict the chlorine concentrations
accurately in time and space? An improved water quality model implies accurate estimation of
concentrations at nodes in time and spWater pollution by wastewater discharge can cause the problem of disinfection byproducts (DBPs) in drinking
water supply. In this study, DBP formation characteristics of soluble microbial products (SMPs) as the main products
of wastewater organic biodegradation were investigated. The results show that SMPs can act as DBP precursors
in simulated wastewater biodegradation process. Under the experimental conditions, stabilized SMPs had
DBPFP (DBP formation potential) yield of around 5.6 μmol mmol−1-DOC (dissolved organic carbon) and DBP
speciation profile different from that of the conventional precursor, natural organic matter (NOM). SMPs
contained polysaccharides, proteins, and humic-like substances, and the latter two groups can act as reactive
DBP precursors. SMP fraction with molecular weight of b1 kDa accounted for 85% of the organic carbon and
65% of the DBP formation. As small SMP molecules are more difficult to remove by conventional water treatment
processes, more efforts are needed to control wastewater-derived DBP problemin water resource managementace at all levels of branching. To enhance the utility of water
quality models dispersion may also be taken into account. In this paper, an eort that led to the
development of an unsteady 2-D convective±dispersive model is presented, and the model output is
compared with the experimental results.