Removal of Natural Organic Matter (NOM), Turbidity, and Color of surface water by integration of enhanced coagulation process and direct filtration

Document Type : Original Article


1 MSc. of Environmental Health Engineering, Shahrekord University of Medical Sciences, Shahrekord, Iran

2 Department of Environmental Health Engineering, School of Public Health, Shahrekord University of Medical Sciences, Shahrekord, Iran

3 Environment Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran, Student Research Committee and Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran


This work assesses the efficiency of integrated enhanced coagulation and direct filtration processes for the removal of color, turbidity, and natural organic matter (NOM) from surface water. The processes were conducted in a simulated pilot. The operating conditions of the treatment process, including pH, FeCl3 dose, and influent flow, were investigated. Following that, its efficiency was evaluated by measuring specific water quality parameters in the output stream including NOM, turbidity, and color. The results showed that under optimum conditions (pH, FeCl3 dose, and influent flow of 6.2, 95 L/h, and 40 mg/l, respectively), the color and turbidity were removed 96% and 95% respectively. According to factors analysis by the Taguchi method, the influence of these factors on the removal of pollutants decreased as follows: pH → FeCl3 dose → influent flow. The results revealed that the integrated enhanced coagulation process and direct filtration can improve the efficiency of colors, turbidity, and NOM removal in water treatment plants.


1-      Ebrahimi A, Taheri E, Pashaee A, Mahdavi M. The effectiveness of polyaluminum ferric chloride (PAFCl) for turbidity and color removal from Isfahan raw water. Desalin Water Treat 2015 .55(7):1966-72.
2-      Matilainen A. Removal of the natural organic matter in the different stage of the drinking water treatment process. Thesis for the degree of Ph.D. University of technology 2007; 4-5.
3-      García I. Removal of Natural Organic Matter to reduce the presence of Trihalomethanes in drinking water. Thesis for the degree of Ph.D. School of Chemical Science and Engineering, Sweden 2011; 4-5.
4-      Mamba BB, Krause RW, Matsebula B, Haarhoff J. Monitoring natural organic matter and disinfection by-products at different stages in two South African water treatment plants. Water SA 2009; 35(1):121-7.
5-      Matilainen A, Vepsäläinen M, Sillanpää M. Natural organic matter removal by coagulation during drinking water treatment: a review. Adv Colloid Interface Sci 2010; 159(2):189-97.
6-      McMeen CR, Benjamin MM. NOM removel by slow sand filtration through iron oxide-coated olivine. J Am Water Works Assoc1997; 89(2):57-71.
7-      Harrelkas F, Azizi A, Yaacoubi A, Benhammou A, Pons MN. Treatment of textile dye effluents using coagulation–flocculation coupled with membrane processes or adsorption on powdered activated carbon. Desalination 2009; 235(1-3):330-9.
8-      Emamjomeh MM, Sivakumar M. Review of pollutants removed by electrocoagulation and electrocoagulation/flotation processes. J. EnvironManag.2009;90(5):1663-79.
9-      Siddiqui M. Membranes for the control of natural organic matter from surface waters. Water Research 2000; 34(13):3355-3370.
10-  Matilainen A, Sillanpää M. Removal of natural organic matter from drinking water by advanced oxidation processes. Chemosphere. 2010; 80(4):351-65.
11-  Eikebrokk B, Juhna T, Østerhus SW. Water treatment by enhanced coagulation–Operational status and optimization issues. TECHNEAU, Deliverable Number D 2006; 5(1).
12-  Eikebrokk B. Coagulation-direct filtration of soft, low alkalinity humic waters. WatSci Tech 1999; 40(9):55-62.
13-  Zouboulis A, Katsoyiannis I. Removal of arsenates from contaminated water by coagulation–direct filtration. Sep SciTech 2002; 37(12):2859-73.
14-  Jaafarzadeh N, Mengelizadeh N, Jalil M, Takdastan A, Alavi N, Niknam N. Removal of zinc and nickel from aqueous solution by chitosan and polyaluminum chloride. Int J Environ Health Eng. 2016; 5(1):16.
15-  Mesdaghinia A, Rafiee MT, Vaezi F, Mahvi A, Torabian A, Ghasri A. Control of disinfection by products formation potential by enhanced coagulation.  Int J Environ Sci Tech. 2006;2(4):335-42.
16-  Gregory J, Duan J. Hydrolyzing metal salts as coagulants. ‎Pure ApplChem .2001;73(12):2017-26.
17-  Davis CC, Edwards M. Coagulation with hydrolyzing metal salts: mechanisms and water quality impacts. Crit Rev Environ SciTechnol. 2014; 44(4):303-47.
18-  Sperczyńska E, Dąbrowska L, Wiśniowska E. Removal of turbidity, colour and organic matter from surface water by coagulation with polyaluminium chlorides and with activated carbon as coagulant aid. Desalin Water Treat. 2016; 57(3):1139-44.
19-  Tubić A, Agbaba J, Dalmacija B, Ivančev-Tumbas I, Dalmacija M. Removal of arsenic and natural organic matter from groundwater using ferric and alum salts: a case study of central Banat region (Serbia). J Environ Sci Health.  2010;45(3):363-9.
20-  Pang FM, Kumar P, Teng TT, Omar AM, Wasewar KL. Removal of lead, zinc and iron by coagulation–flocculation. J Taiwan InstChemEng. 2011; 42(5):809-15.
21-  Bojic AL, BojicD, Andjelkovic T. Removal of Cu2+ and Zn2+ from model wastewaters by spontaneous reduction–coagulation process in flow conditions. J Hazard Mater. 2009; 168(2):813-9.