American Journal of Civil Engineering
Volume 4, Issue 5, September 2016, Pages: 205-215
Received: Jul. 14, 2016;
Published: Jul. 15, 2016
Views 7188 Downloads 492
Frederick W. Pontius, Department of Civil Engineering, California Baptist University, Riverside, California, USA
Inorganic aluminum or iron salts have been used for many decades to coagulate colloidal particles in surface water prior to flocculation, sedimentation and/or filtration. Although effective, inorganic coagulants have several disadvantages including large chemical dosages required for treating eutrophic waters, large volumes of chemical sludge produced, and toxic effects of metallic coagulants on the aquatic environment. Chitosan is a natural cellulose-like copolymer of glucosamine and N-acetyl-glucosamine. Because of their biodegradability chitosan-based materials have been suggested as a more eco-friendly coagulant for water and wastewater treatment. Chitosan was an effective coagulant in several prior laboratory studies. Practical application of chitosan as a drinking water treatment coagulant is evaluated here through a series of jar tests. The effectiveness of chitosan is compared to aluminum sulphate and ferric chloride with regard to treatment of algal-ladened waters. The optimum chemical dose for coagulation, optimum pH, and effectiveness for algae removal was determined for each coagulant. Practical aspects of applying chitosan at full-scale and the impact of feeding this chemical on overall treated water quality are addressed.
Frederick W. Pontius,
Chitosan as a Drinking Water Treatment Coagulant, American Journal of Civil Engineering.
Vol. 4, No. 5,
2016, pp. 205-215.
Nogaro, G. and A. J. Burgin, V. A. Schoepfer, M. J. Konkler, K. L. Bowman, and C. R. Hammerschmidt. 2013. Aluminum sulfate (alum) application interactions with coupled metal and nutrient cycling in a hypereutrophic lake ecosystem. Environmental Pollution, vol. 176, 2013, pp. 267-274.
M. Rinaudo. “Chitin and chitosan: Properties and applications,” Progress in Polymer Science, vol. 31, 2006, pp. 603–632.
F. Renault, B. Sancey, P.-M. Badot, G. Crini. “Chitosan for coagulation/flocculation processes – An eco-friendly approach” European Polymer Journal, vol. 45, 2009, pp. 1337-1348.
S. A. Fast, B. Kokabian and V. G. Gude. “Chitosan enhanced coagulation of algal turbid waters – Comparison between rapid mix and ultrasound coagulation methods.” Chemical Engineering Journal, vol. 244, 2014, pp. 403-410.
H. Altaher. “The use of chitosan as a coagulant in the pre-treatment of turbid sea water.” Journal of Hazardous Materials, vol. 233-234, 2012, pp. 97-102.
A. L. Ahmad, N. H May Yasin, J. C. Derek, and J. K. Lim. “Optimization of Microalgae Coagulation Processes Using Chitosan.” Chemical Engineering Journal, vol. 173, 2011, pp. 879-882.
M. A. Abu Hassan and M. H. Puteh. “Pretreatment of palm oil effluent (POME): a comparison study using chitosan and alum.” MJCE, vol. 19, 2007, 128-141.
R. Yang, H. Li, M. Huang, H. Yang, A. Li. “A review on chitosan-based flocculants and their applications in water treatment.” Water Research, vol. 95, 2016, pp. 59-89.
EPA. Manual for the Certification of Laboratories Analyzing Drinking Water; Criteria and Procedures Quality Assurance. Fifth edition. EPA 815-R-05-004. January 2005.
R. Divakaran and V. N. Sivasankara Pillai. “Flocculation of algae using chitosan.” Journal of Applied Phycology, vol. 14, 2001, 419-422.
ASTM D 2035-08, “Standard Practice for Coagulation- Flocculation Jar Test of Water.” West Conshohocken, PA: American Society for Testing and Materials.
APHA. Standard Methods for the Examination of Water and Wastewater. 20th Edition. Washington, D. C.: American Public Health Association, 1998.
Hach Method 10029. USEPA Membrane Filter Method. Coliforms—Total and E. coli. DOC316.53.001213.
L. Rizzo, A. Di Gennaro, M. Gallo, and V. Belgiorno. “Coagulation/chlorination of surface water: a comparison between chitosan and metal salts.” Separation and Purification Technology, vol. 62, 2008, 79-85.
NSF Standard 60-2015. Drinking Water Treatment Chemicals – Health Effects. Ann Arbor, MI: NSF International.