Abstract
Reduction methods in trihalomethane formation potential (THMFP) were investigated for a treated sewage, fulvic acid in a treated sewage, fulvic acid in a leaf mold and humic acid in a leaf mold by oxidation with ozone, potassium permanganate (KMnO4), adsorption with activated carbon and their combination.
The molecular weight distributions of the three humic substances were determined using a Sephadex G-25 or G-75 before and after the ozonation. The eluted solution was divided into four or three groups and for each THMFP per unit organic carbon was determined. THMFPs of the fulvic acid and the humic acid in leaf mold were reduced effectively by ozonation alone. On the other hand, THMFPs of the treated sewage and the fulvic acid in treated sewage were not reduced significantly by the oxidation with ozone or KMnO4, though THMFP was reduced considerably by the adsorption with activated carbon.
The molecular weight of the fulvic acid and the humic acid in leaf mold fairly decreased by ozonation, and their THMFPs were reduced significantly since the decomposed lower molecular weight fractions had very small THMFPs per unit organic carbon. The molecular weights of the smaller fulvic acid in treated sewage were reduced more by ozonation, but the THMFP showed no significant decrease.
