Effect of coagulation on different NOM fractions in spent filter backwash water

Natural organic matter (NOM) is one of the most important parameters in water and wastewater reuse subjects. The aim of this study was to determine the effect of coagulation with two different coagulants (polyaluminium ferric chloride and ferric chloride) on fractional composition natural organic matter that contain in spent filter backwash water (SFBW) produced in water treatment plant. Conventional jar test apparatus was used for the coagulation procedure and the NOM was fractionated into hydrophobic, transphilic and hydrophilic fractions. NOM fractionation was conducted by DAX-8 (Supelite) and XAD-4 (Amberlite) resins. The results showed that at optimum dose of FeCl3 ( 30 mg/L) NOM fractions of the treated SFBW include 56 (± 4.6) %, 26 (± 3.7) % and 18 (± 3) % of hydrophobic, hydrophilic and transphilic fractions, respectively. These fractions for PAFCl (13 mg/L) were 68 (± 4.8) %, 22 (± 3.5) % and 10 (± 2.3) % respectively. It was concluded that the performance of PAFCl for organic matter removal was better than FeCl3. However, FeCl3was more efficient than PAFCl for the removal of hydrophobic fraction and vice versa was occurred for the removal of transphilic fraction.

کلیدواژه ها:

Coagulation ، natural organic matter fractionation ، spent filter backwash water ، XAD resins ، PAFCl& FeCl3