Alternatives to the use of synthetic organic coagulant aids in drinking water treatment: improvements in the application of the crude extract of Moringa oleifera seed

[EN] Drinking water treatment is a process based on multiple stages that has a main objective to provide water safe enough to be consumed by humans. Coagulation–flocculation is used to remove colloidal and suspended solids. This process improves the performance of subsequent stages (as sedimentation or filtration) as well as the water quality with a desired end-use. For many years, inorganic and organic synthetic polyelectrolytes have been used in coagulation–flocculation processes. However, its use has been deeply studied recently to determine the potential impact of residual concentration of these substances on human health and the environment. Strict regulations limit the concentration of free residual monomer after the addition of polyacrylamide (PAM) in drinking water treatment and study the effect of interaction of the residues with disinfection products. Therefore, in the last years there has been a resurgence of interest to use natural materials with the same performance that synthetic, but with lower hazard for the environment and humans. This work studies the use of the flocculant extracted from Moringa oleifera seed, in combination with polyaluminum chloride (PAC). The performance is compared with the combination PAC–PAM in terms of coagulant activity and physical–chemical quality of the water treated. Jar test was carried out using two types of natural water (with presence of bentonites) and different combinations of coagulant and flocculants. Results show that coagulant activity of PAC–Moringa combination is comparable with the results obtained with PAC–PAM, reducing initial turbidity up to 90% in all the tests. With regard to physical–chemical quality of the treated water, PAC–Moringa produces values under the drinking water quality standards for all the parameters analyzed. It is remarkable that the decrease of 50% in the trihalomethanes formation potential rate shown for PAC–Moringa combination, observed when treating natural water with presence of bentonites. Therefore, the results obtain in this work encourage the use of Moringa oleifera extract as a natural, low cost, effective, and low-toxicity alternative to the use of synthetic organic polyelectrolytes as polyacrylamide for drinking water treatment.This research has been done in the framework of the project “Study of synthetic and natural coagulants susceptible of being used in the water treatment plant of “Ribarroja del Turia” (Valencia) as substitutes for polyacrylamide”. The authors wish to thank the staff of the laboratory of the Department of Water Quality of the company “Aguas de Valencia” located in La Presa (Manises) for its collaboration in the water tests of this work.García Fayos, B.; Arnal Arnal, JM.; Monforte Monleon, L.; Sancho Fernández, MP. (2015). Alternatives to the use of synthetic organic coagulant aids in drinking water treatment: improvements in the application of the crude extract of Moringa oleifera seed. Desalination and Water Treatment. 55(13):3635-3645. doi:10.1080/19443994.2014.939487S363536455513Van Benschoten, J. E., & Edzwald, J. K. (1990). Chemical aspects of coagulation using aluminum salts—I. Hydrolytic reactions of alum and polyaluminum chloride. Water Research, 24(12), 1519-1526. doi:10.1016/0043-1354(90)90086-lBOLTO, B. (1995). Soluble polymers in water purification. Progress in Polymer Science, 20(6), 987-1041. doi:10.1016/0079-6700(95)00010-dCrapper, D. R., Krishnan, S. S., & Dalton, A. J. (1973). Brain Aluminum Distribution in Alzheimer’s Disease and Experimental Neurofibrillary Degeneration. Science, 180(4085), 511-513. doi:10.1126/science.180.4085.511Davison, A. M., Oli, H., Walker, G. S., & Lewins, A. M. (1982). WATER SUPPLY ALUMINIUM CONCENTRATION, DIALYSIS DEMENTIA, AND EFFECT OF REVERSE-OSMOSIS WATER TREATMENT. The Lancet, 320(8302), 785-787. doi:10.1016/s0140-6736(82)92678-2Rondeau, V., Commenges, D., Jacqmin-Gadda, H., & Dartigues, J.-F. (2000). Relation between Aluminum Concentrations in Drinking Water and Alzheimer’s Disease: An 8-year Follow-up Study. American Journal of Epidemiology, 152(1), 59-66. doi:10.1093/aje/152.1.59Rondeau, V. (2001). RE: ALUMINUM IN DRINKING WATER AND COGNITIVE DECLINE IN ELDERLY SUBJECTS: THE PAQUID COHORT. American Journal of Epidemiology, 154(3), 288-a-290. doi:10.1093/aje/154.3.288-aGauthier, E., Fortier, I., Courchesne, F., Pepin, P., Mortimer, J., & Gauvreau, D. (2000). Aluminum Forms in Drinking Water and Risk of Alzheimer’s Disease. Environmental Research, 84(3), 234-246. doi:10.1006/enrs.2000.4101Kawamura, S. (1976). Considerations on Improving Flocculation. Journal - American Water Works Association, 68(6), 328-336. doi:10.1002/j.1551-8833.1976.tb02421.xA.D. Faust, O.M. Aly, Chemistry of Water Treatment, Butterworths, Boston, MA, 1983, pp. 326–328.Martenson, C. H., Sheetz, M. P., & Graham, D. G. (1995). In Vitro Acrylamide Exposure Alters Growth Cone Morphology. Toxicology and Applied Pharmacology, 131(1), 119-129. doi:10.1006/taap.1995.1053Kaggwa, R. C., Mulalelo, C. I., Denny, P., & Okurut, T. O. (2001). The impact of alum discharges on a natural tropical wetland in uganda. Water Research, 35(3), 795-807. doi:10.1016/s0043-1354(00)00301-8Dearfield, K. L., Abernathy, C. O., Ottley, M. S., Brantner, J. H., & Hayes, P. F. (1988). Acrylamide: its metabolism, developmental and reproductive effects, genotoxicity, and carcinogenicity. Mutation Research/Reviews in Genetic Toxicology, 195(1), 45-77. doi:10.1016/0165-1110(88)90015-2McCollister, D. D., Oyen, F., & Rowe, V. K. (1964). Toxicology of acrylamide. Toxicology and Applied Pharmacology, 6(2), 172-181. doi:10.1016/0041-008x(64)90103-6BOLTO, B., & GREGORY, J. (2007). Organic polyelectrolytes in water treatment. Water Research, 41(11), 2301-2324. doi:10.1016/j.watres.2007.03.012World Health Organization, Guidelines for drinking-water quality: Incorporating first and second addenda, in: World Health Organization (Ed.) Recommendations, third ed., vol. 1, World Health Organization, Geneva, 2008, pp. 188–194.Hamilton, M. A. (1994). A Statistician’s View of the U.S. Primary Drinking Water Regulation on Coliform Contamination. Environmental Science & Technology, 28(11), 1808-1811. doi:10.1021/es00060a009J. Criddle, A review of the mammalian and aquatic toxicity of polyelectrolites, NR 2545 Medmenhan, Foundation for Water Research 1990.Hebert, A., Forestier, D., Lenes, D., Benanou, D., Jacob, S., Arfi, C., … Levi, Y. (2010). Innovative method for prioritizing emerging disinfection by-products (DBPs) in drinking water on the basis of their potential impact on public health. Water Research, 44(10), 3147-3165. doi:10.1016/j.watres.2010.02.004Gerecke, A. C., & Sedlak, D. L. (2003). Precursors ofN-Nitrosodimethylamine in Natural Waters. Environmental Science & Technology, 37(7), 1331-1336. doi:10.1021/es026070iCharrois, J. W. A., Arend, M. W., Froese, K. L., & Hrudey, S. E. (2004). DetectingN-Nitrosamines in Drinking Water at Nanogram per Liter Levels Using Ammonia Positive Chemical Ionization. Environmental Science & Technology, 38(18), 4835-4841. doi:10.1021/es049846jS.A.A. Jahn, Proper use of African natural coagulants for rural water supplies- Research in the Sudan and a guide for new projects, Deutsche Gesellschaft für Technische Zusammenarheit (GTZ), Eschborn, 1986.Dorea, C. C. (2006). Use of Moringa spp. seeds for coagulation: a review of a sustainable option. Water Science and Technology: Water Supply, 6(1), 219-227. doi:10.2166/ws.2006.027Kawamura, S. (1991). Effectiveness of Natural Polyelectrolytes in Water Treatment. Journal - American Water Works Association, 83(10), 88-91. doi:10.1002/j.1551-8833.1991.tb07236.xLee, S. H., Lee, S. O., Jang, K. L., & Lee, T. H. (1995). Microbial flocculant from Arcuadendron sp. TS-49. Biotechnology Letters, 17(1), 95-100. doi:10.1007/bf00134203Effect of synthetic and natural coagulant on lignin removal from pulp and paper wastewater. (1997). Water Science and Technology, 35(2-3). doi:10.1016/s0273-1223(96)00943-2Broekaert, W. F., Cammue, B. P. A., De Bolle, M. F. C., Thevissen, K., De Samblanx, G. W., Osborn, R. W., & Nielson, K. (1997). Antimicrobial Peptides from Plants. Critical Reviews in Plant Sciences, 16(3), 297-323. doi:10.1080/07352689709701952Jahn, S. A. A. (1988). Using Moringa Seeds as Coagulants in Developing Countries. Journal - American Water Works Association, 80(6), 43-50. doi:10.1002/j.1551-8833.1988.tb03052.xMuyibi, S. A., & Okuofu, C. A. (1995). Coagulation of low turbidity surface waters withMoringa oleiferaseeds. International Journal of Environmental Studies, 48(3-4), 263-273. doi:10.1080/00207239508710996Ndabigengesere, A., Narasiah, K. S., & Talbot, B. G. (1995). Active agents and mechanism of coagulation of turbid waters using Moringa oleifera. Water Research, 29(2), 703-710. doi:10.1016/0043-1354(94)00161-yOkuda, T., Baes, A. U., Nishijima, W., & Okada, M. (2001). Isolation and characterization of coagulant extracted from moringa oleifera seed by salt solution. Water Research, 35(2), 405-410. doi:10.1016/s0043-1354(00)00290-6Ghebremichael, K. A., Gunaratna, K. R., Henriksson, H., Brumer, H., & Dalhammar, G. (2005). A simple purification and activity assay of the coagulant protein from Moringa oleifera seed. Water Research, 39(11), 2338-2344. doi:10.1016/j.watres.2005.04.012Sánchez-Martín, J., Ghebremichael, K., & Beltrán-Heredia, J. (2010). Comparison of single-step and two-step purified coagulants from Moringa oleifera seed for turbidity and DOC removal. Bioresource Technology, 101(15), 6259-6261. doi:10.1016/j.biortech.2010.02.07

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