Alum sludge dewatering using Moringa oleifera as a conditioner

• Published in: Water, air, and soil pollution Vol. 158; no. 1-4; pp. 153 - 167
• Main Authors: Ghebremichael, K.A, Hultman, B
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.10.2004; Springer Nature B.V
• Subjects: alum; Alum sludge; Applied sciences; Chemical sludge; coagulants; column drainage; CST; Dewatering; Drainage; Drinking water; electrolytes; Environmental monitoring; Exact sciences and technology; filtration; General treatment and storage processes; Moringa oleifera; Pollution; polyelectrolyte; Polyelectrolytes; Polymers; seed extracts; sewage sludge; sewage treatment; Shear strength; Sludge; sludge conditioning; Sludge drying; SRF; Wastes; Water treatment; Water treatment plants; water treatment sludge; Sweden; Seeds; Waste treatment; SRF; Dehydration; Moringa oleifera; Flocculation reagent; Dicotyledones; Angiospermae; Moringaceae; Conditioning; Mud; Aluminium sulfate; Thickening; water treatment sludge; Filtration; column drainage; CST; Shear strength; sludge conditioning; alum; Polyelectrolyte; Drinking water treatment plant; Flocculation; Spermatophyta; Performance; Comparative study
• ISSN: 0049-6979; 1573-2932; 1573-2932
• DOI: 10.1023/B:WATE.0000044852.23764.9c

An active component of Moringa oleifera (MO) has been used in comparison with synthetic polymers and alum for the conditioning of chemical sludge from a drinking water treatment plant. The comparison was based on dewatering characteristics of the conditioned sludge determined by capillary suction time (CST), specific resistance to filtration (SRF), sand column drainage and shear strength tests. The results indicated that MO showed comparable conditioning effect as alum. Polyelectrolytes were more effective than MO and alum. Sludge conditioned with MO and alum, as in dual chemical conditioning, showed better results than MO alone. According to CST, SRF and sand drainage results, optimum doses for MO, alum and polyelectrolytes were 125, 63, and 1.8 kg/t, respectively. Comparison of the two polyelectrolytes showed that the cationic polyelectrolyte was more effective. For sand drainage tests both polyelectrolytes improved the drainage rate by 2 orders of magnitude. MO and alum improved the drainage rate by about 4.2 times. On the other hand, the improvements in cake solids concentration were similar for all the chemical conditioners. Flocs from MO and alum were relatively stronger compared to those of the polyelectrolytes. From the results of the study it could be concluded that MO alone or in combination could be effectively used and replace alum for dewatering of chemical sludge.[PUBLICATION ABSTRACT]