AWWA WQTC69369

This study examines the Moringa oleifera seed (a tropical tree) as a coagulant, adsorbent and filter aid. Theplant is drought resistant and most of its parts are useful for various applications. Extracts fromthe seed were investigated for coagulation, filter aid and adsorption. The coagulation potential ofM. oleifera was compared against alum and iron salts, and was used as a filter aid to enhance theripening of slow sand filters. Activated carbon prepared from the seed shell and solid residues aftercoagulant extraction were used for the adsorption of chromium. With respect to coagulation ofturbid natural and synthetic waters, M. oleifera showed similar performance as metal salts andwas effective in a wider range of pH. The M. oleifera coagulant was found to be effective as acoagulant aid in combination with metal salts, and improved organic removal was observed. Slow sandfiltration (SSF) studies, in combination with M. oleifera as a filter aid, indicated that during thestart-up use of filter aid, the ripening period was significantly reduced compared to SSF without filteraid. It was observed that intermittent and short period dosing of M. oleifera was sufficient toenhance ripening as continuous dosage resulted in excessive headloss development. Adsorptionstudies for the removal of chromium were carried out in batch experiments and the effects ofadsorbent dose, contact time, initial metal concentrations, metal speciation and pH were analyzed.Adsorption studies indicated that the seed (after coagulant extraction) achieved more than 94%and 43% removal of Cr (III) and Cr (VI), respectively. The activated carbon from the seed shellremoved 99.9% and 83% Cr (III) and Cr (VI), respectively. The studies demonstrated that thedifferent applications of the bio-material can be integrated to achieve optimum utilization of theresource both in water and wastewater treatment. Includes 24 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

11

File Size:

1 file , 860 KB