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Effectiveness of chitosan as natural coagulant aid in removal of turbidity and bacteria from turbid waters

Mehdinejad, M.H. and Bina, B. and Nikaeen, M. and Attar, H.M. (2009) Effectiveness of chitosan as natural coagulant aid in removal of turbidity and bacteria from turbid waters. Journal of Food, Agriculture and Environment, 7 (3-4). pp. 845-850. ISSN 14590255 (ISSN)

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Abstract

There has been considerable interest in the development of natural coagulants such as chitosan. By using natural coagulants, considerable savings in chemicals and sludge handling cost may be achieved. Chitosan, a natural linear biopolyaminosaccharide, is obtained by alkaline deacetylation of chitin. Present study is aimed to examine the effects of aluminium sulfate (alum) as coagulant in conjunction with chitosan as coagulant aid on removal of turbidity and bacteria from turbid waters. These tests were carried out using artificial water and kaoline as model suspensions to represent the wide range of natural turbid waters. A conventional jar test apparatus was employed for the tests. After determining of optimum mixing intensity and duration, alum suspensions were added to the samples and after one minute, the desired doses of natural chitosan were added. In optimum condition, residual Al+3 in treated water was less than 0.2 mg/l and meets the EPA guidelines. Turbidity removal efficiency was 74.3- 98.2% by chitosan at a pH 7.0-7.5 for all turbidities. In addition, chitosan significantly reduced the required dosage of primary coagulant 50-87.5%. Bacteria reduction of 2-4 log units (99 - 99.99%) was obtained within the first 1 to 2 h of treatment. Overall results indicate that E.coli was removed better than S. faecalis. The main effects of coagulation by chitosan on bacteria are enmeshment and stack on the microbial cell surface. We demonstrated that optimal design method is an efficient approach for optimization of coagulation-flocculation process and appropriate for raw water treatment.

Item Type: Article
Additional Information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - J. Food Agric. Environ. [Field not mapped to EPrints] AD - Department of Environmental Health Engineering, School of Public Health, Isfahan University of Medical Sciences, Hezar jarib Avenue, Isfahan, Iran [Field not mapped to EPrints] AD - Department of Environmental Health Engineering, School of Pyrapezeshki and Health, Golestan University of Medical Sciences, Gorgan, Iran [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled Keywords: Bacteria removal, Chitosan, Coagulant aid, Treatment, Water, aluminum potassium sulfate, chitosan, kaolin, water, article, cell surface, controlled study, Enterococcus faecalis, Escherichia coli, nonhuman, pH measurement, turbidity
Subjects: مقالات نمایه شده محققین دانشگاه در سایت ,Web of Science ,Scopus
Divisions: معاونت تحقیقات و فناوری
Depositing User: GOUMS
Date Deposited: 18 Apr 2015 09:16
Last Modified: 01 Mar 2017 09:35
URI: http://eprints.goums.ac.ir/id/eprint/2266

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