Effects of biological aerated filter (BAF), sand filter (SF), biological activated carbon (BAC), alum coagulation,
and Moringa oleifera coagulation on the removal of DOC and DON from reservoir water were
investigated. The DOC removal efficiency was in the following sequence: BAC (56%), BAF (51%), SF (45%),
alum (27%), and M. oleifera (22%). The trend for DON removal efficiency was similar to that of DOC. The
better performance by BAC was attributed to the effective microbial breakdown of organic matter and
the adsorption of some molecules onto activated carbon. The organic content with a molecular weight
(MW) of less than 10 kDa accounted for more than 45% of the total DOC, whereas a MWof less than 1 kDa
accounted for 50% of the total DON. The biofilters removed the entire MW range of organic contents,
unlike the coagulants which only removed organics with a MW of more than 10 kDa. Consistent with
greater DOC and DON removal, BAC led to greater removal of DBP precursors as shown by DBP formation
potentials.