Characterisation of natural organic matter (NOM) in water treatment using seed extracts

This study evaluates the potential of using natural plant extract in water treatment and its corresponding effects on the final treated water. Fluorescence excitation-emission matrices (EEMs) were used to characterise NOM in water treated using Okra crude extract (CE) as a coagulant in a jar test experiment. The effect of thermal treatment (TT) was also examined. Four fluorescent peaks, tryptophan-like (T), tyrosine-like (B) and humic and fulvic acid-like (A and C) were found to be more dominant in CE samples than TT samples. The results further revealed that minimal dissolved organic carbon (DOC) addition and high turbidity removal efficiency were recorded in TT compared with CE samples. It is noteworthy that the pH of the treated water remained largely unaffected from initial 7.22 to 7.17 and 7.19 in TT and CE respectively due to their buffering capacity. Overall, the water treatment potential of Okra extract has demonstrated considerable efficiency in removing turbidity in water. Elevated NOM concentration was observed following use of crude extract. However, this increase in crude extract treated water NOM can be controlled by simple heat treatment.