Advances in Environmental Biology

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1 AENSI Journals Advances in Environmental Biology ISSN EISSN Journal home page: Evaluation of Three Coagulants Efficiency in Turbidity Removal of Karoun River Water Heidar Ali Kashkuli, Masoud Sadeghi-Mianroudi, Davoud Khodadadi Dehkordi Department of Irrigation, College of Agriculture, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran. A R T I C L E I N F O Article history: Received 3 August 2014 Received in revised form 27 September 2014 Accepted 24 October 2014 Available online 3 November 2014 Keywords: PACL, Alum, Ferric Chloride, Turbidity removal. A B S T R A C T In this research, three coagulants efficiency including Polyaluminum Chloride (PACL), Aluminum Sulfate (Alum) and Ferric Chloride were evaluated in turbidity removal of Karoun River water in Ahvaz city of Iran. For evaluating of the coagulants efficiency used from 11 different turbidity ranges from 0 to > NTU considering different turbidities of Karoun River water. The results showed that PACL and Ferric Chloride had the better results in turbidity removal in comparison with Alum. Besides, the efficiency of PACL was better than Ferric Chloride in turbidity removal of Karoun River in initial turbidity of > 6500 NTU. So, it was recommended to use form PACL in this conditions AENSI Publisher All rights reserved. To Cite This Article: Heidar Ali Kashkuli, Masoud Sadeghi-Mianroudi, Davoud Khodadadi Dehkordi., Evaluation of Three Coagulants Efficiency in Turbidity Removal of Karoun River Water. Adv. Environ. Biol., 8(13), , 2014 INTRODUCTION Considering the increasing of population and the raise of water consumption in cities, it is important to provide treated water properly. Actually, the need for drinking water of high quality is increasing, as the nonpolluted water sources are continuously decreasing. Water treatment industry is among the most important industries in many countries such as Iran. Coagulation, flocculation, sedimentation, filtration and disinfection are the most common treatment processes used in the production of drinking water. Coagulation/flocculation processes are of great importance in solid-liquid separation practice [27,1]. The coagulation process is used to destabilize colloidal material in water by the addition of a chemical agent. It requires rapid mixing to quickly disperse the coagulant and subsequently flocculation process. Flocculation is the formation of aggregates of the destabilized colloids and requires gentle mixing to allow effective collisions between particles to form heavy flocs, which can be removed from water by settlement [1]. Nowadays by using usual salts of Iron and aluminum a new group of coagulants named inorganic polymers have been produced and used in many countries of the world especially China, Japan, Russia and Western European countries [26,12]. Many kinds of inorganic polymers have been developed including aluminum-based, iron-based, inorganic inorganic composite flocculants, inorganic organic composite flocculants, and multifunctional composite IPFs [16,17,24,13,8,18,19,25]. Among them, polyaluminum chloride (PACl) is one of the typical kinds and has become most widely applied. The property and general coagulation behavior of inorganic polymers have been extensively investigated [17,24,13,8,25,4,20,23,26]. Inorganic metallic salts make unstable the particles by pressing double electrical layers around colloid particles, while polymers perform instability functions by absorption in colloid particle surface and making bridge among polymer particles [10]. The main objective in this research is evaluation of three coagulants efficiency including Polyaluminum Chloride (PACL), Aluminum Sulfate (Alum) and Ferric Chloride in turbidity removal of Karoun River water in water treatment plant (WTP) of Kut-e Amir in different turbidity ranges of 0 to > NTU. MATERIALS AND METHODS This research was conducted in WTP of Kut-e Amir that was located in south east of Ahvaz city of Iran. It is providing the drinking water of south east of Ahvaz city and water resource of it is Karoun River. This WTP has seven clarifier units that can purify m 3 /day of Karoun River water. Now, the coagulant that is used in WTP of Kut-e Amir is Ferric Chloride and in high turbidity conditions (> 300 NTU) Besfloc is used as a Corresponding Author: Davoud Khodadadi Dehkordi, Department of Irrigation, College of Agriculture, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran. Ph: ( ), Davood_kh70@yahoo.com.

2 1042 Davoud Khodadadi Dehkordi et al, 2014 coagulant aid. In this research, three coagulants including Polyaluminum Chloride (PACL) ([Al 2 (OH)nCl 6 -n xh 2 O]m (m 10,n=3~5)), Aluminum Sulfate (Alum) (Al 2 (SO 4 ) 3.18H 2 O) and Ferric Chloride (Fecl 3.6H 2 O) were evaluated. For evaluating of three coagulants efficiency in this research, used from 11 different turbidity ranges from 0 to > NTU according to Table 1, considering different turbidities of Karoun River water. The coagulants injection ranges in every turbidity range achieved from the statistic evaluation of WTP of Kut-e Amir related to current ten years in this field. Table 1 shows the turbidity ranges and injection ranges of the coagulants and coagulant aid in this research. Table 1: The turbidity ranges and injection ranges of the coagulants and coagulant aid. Turbidity range (NTU) Coagulants injection range (ppm) Injection range of coagulant aid (ppm) < > For evaluating of three coagulants efficiency, jar-test was done for every turbidity range. The jar-test apparatus with model of AQUALYTIC had six dishes (Figure 1). Actually, about 7 to 30 jar-test were done for every turbidity range. After determination of water turbidity in every range (according to Table 1), sample was transferred to jar-test dishes and jar-test apparatus was started with 180 to 190 rpm speed. Then, coagulants in minimum and maximum amounts in every turbidity range were added and after 15 to 20 seconds, coagulant aid in minimum and maximum amounts were added. After 1 minute, jar-test apparatus speed was reduced to 50 to 60 rpm. Then, after 15 minutes, the apparatus was turned off and after 10 minutes, it s taken 25 ml sample in 1 cm depth of water surface in dishes for measuring turbidity. In this research, coagulant aid (Besfloc) was added when samples turbidity were > 300 NTU. Turbidity of samples measured by turbidity meter with model of HACH2100N (Figure 2). Fig. 1: The jar-test apparatus with model of AQUALYTIC. RESULTS AND DISCUSSION - Evaluation of jar-test results in different ranges of turbidity: - Different turbidity ranges of < 50, and NTU: Jar-test results in turbidity ranges of < 50, and NTU with the minimum and maximum coagulants injection are shown in Figures 3-8.

3 1043 Davoud Khodadadi Dehkordi et al, 2014 Fig. 2: The turbidity meter with model of HACH2100N. Fig. 3: Jar-test results in turbidity range of < 50 NTU with the minimum coagulants injection (1 ppm) and Fig. 4: Jar-test results in turbidity range of < 50 NTU with the maximum coagulants injection (1.5 ppm) and Fig. 5: Jar-test results in turbidity range of NTU with the minimum coagulants injection (1.5 ppm) and

4 1044 Davoud Khodadadi Dehkordi et al, 2014 Fig. 6: Jar-test results in turbidity range of NTU with the maximum coagulants injection (1.9 ppm) and Fig. 7: Jar-test results in turbidity range of NTU with the minimum coagulants injection (2.4 ppm) and Fig. 8: Jar-test results in turbidity range of NTU with the maximum coagulants injection (2.9 ppm) and According to Figures 3-8, Ferric Chloride had the best result in turbidity removal. After that, PACL was very close to Ferric Chloride in turbidity removal but its effect was a little less than Ferric Chloride. Then, the effect of Alum in turbidity removal was the least. As the results showed, in low turbidity (< 130 NTU) and without coagulant aid, turbidity removal efficiency of Ferric Chloride was better than PACL, although they were very close together. - Turbidity range of NTU: Jar-test results in turbidity range of NTU with the minimum and maximum coagulants injection are shown in Figures Fig. 9: Jar-test results in turbidity range of NTU with the minimum coagulants injection (3 ppm) and

5 1045 Davoud Khodadadi Dehkordi et al, 2014 Fig. 10: Jar-test results in turbidity range of NTU with the maximum coagulants injection (3.5 ppm) and According to Figures 9-10, PACL had the better turbidity removal efficiency than Ferric Chloride and Alum. Considering coagulant aid (Besfloc) was added when samples turbidity were > 300 NTU, therefore, the results showed that PACL in border of adding coagulant aid, showed better result. This can be a beginning for the better efficiency of PACL in turbidity removal in high turbidity ranges and In addition, the effect of Alum in turbidity removal was the least. - Different turbidity ranges of , , and NTU: Jar-test results in turbidity ranges of , , and NTU with the minimum and maximum coagulants injection are shown in Figures Fig. 11: Jar-test results in turbidity range of NTU with the minimum coagulants injection (3 ppm) and the minimum coagulant aid ( ppm). Fig. 12: Jar-test results in turbidity range of NTU with the maximum coagulants injection (3.5 ppm) and the maximum coagulant aid (0.01 ppm).

6 1046 Davoud Khodadadi Dehkordi et al, 2014 Fig. 13: Jar-test results in turbidity range of NTU with the minimum coagulants injection (3.5 ppm) and the minimum coagulant aid (0.025 ppm). Fig. 14: Jar-test results in turbidity range of NTU with the maximum coagulants injection (4 ppm) and the maximum coagulant aid (0.053 ppm). Fig. 15: Jar-test results in turbidity range of NTU with the minimum coagulants injection (3.5 ppm) and the minimum coagulant aid (0.05 ppm). Fig. 16: Jar-test results in turbidity range of NTU with the maximum coagulants injection (4.1 ppm) and the maximum coagulant aid ( ppm).

7 1047 Davoud Khodadadi Dehkordi et al, 2014 Fig. 17: Jar-test results in turbidity range of NTU with the minimum coagulants injection (3.5 ppm) and the minimum coagulant aid (0.1 ppm). Fig. 18: Jar-test results in turbidity range of NTU with the maximum coagulants injection (4.5 ppm) and the maximum coagulant aid (0.2 ppm). According to Figures 11-18, Ferric Chloride had the best result in turbidity removal. After that, PACL was very close to Ferric Chloride in turbidity removal but its effect was a little less than Ferric Chloride. Then, the effect of Alum in reducing turbidity was the least. In this research, in high turbidity ranges (> 300 NTU), coagulant aid (Besfloc) was added. Therefore, as the results showed, with adding of coagulant aid (Besfloc) the efficiency of Ferric Chloride in turbidity removal became better than PACL, although they were very close together. - Turbidity range of NTU: Jar-test results in turbidity range of NTU with the minimum and maximum coagulants injection are shown in Figures Fig. 19: Jar-test results in turbidity range of NTU with the minimum coagulants injection (4 ppm) and the minimum coagulant aid (0.2 ppm).

8 1048 Davoud Khodadadi Dehkordi et al, 2014 Fig. 20: Jar-test results in turbidity range of NTU with the maximum coagulants injection (4.55 ppm) and the maximum coagulant aid (0.3 ppm). According to Figures 19-20, Ferric Chloride had the better result in comparison with PACL in turbidity removal up to 6500 NTU. However, in higher turbidity (more than 6500 NTU), the efficiency of PACL became better than Ferric Chloride in spite of adding coagulant aid. Also, the effect of Alum in turbidity removal was the least. - Different turbidity ranges of and > NTU: Jar-test results in turbidity ranges of and > NTU with the minimum and maximum coagulants injection are shown in Figures Fig. 21: Jar-test results in turbidity range of NTU with the maximum coagulants injection (4.6 ppm) and the maximum coagulant aid (0.3 ppm). Fig. 22: Jar-test results in turbidity range of > NTU with the maximum coagulants injection (4.6 ppm) and the maximum coagulant aid (0.3 ppm). According to Figures 21-22, PACL had the better result in comparison with Ferric Chloride in turbidity removal, although they were very close together. According to Figures 3-22, in high initial turbidity ranges, turbidity after jar-test with adding of PACL, Ferric Chloride and coagulant aid was more than 5 NTU. Considering turbidity standard of drinking water in Iran (5 NTU), it is clear that with increasing of initial turbidity and with injection of Table 1 doses, turbidity after jar-test increases (more than 5 NTU). Therefore, it shows that in high initial turbidity, coagulants and coagulant aid doses in Table 1 are not enough and injection of Table 1 doses should be increased.

9 1049 Davoud Khodadadi Dehkordi et al, 2014 According to Figures 3-22, it is clear that PACL and Ferric Chloride had the better results in turbidity removal in comparison with Alum. This result is confirmed by Baghvand et al [1]; Kord-Mostafapoor et al [6] and Sid-Mohammadi et al [14]. Considering Ferric Chloride is cheaper than PACL and Alum, WTPs prefer to use from Ferric Chloride. Sid-Mohammadi et al [14] recommended using of Ferric Chloride for turbidity removal in comparison with PACL, because it was cheaper and more available than PACL. Economic analysis in WTP of Kut-e Amir showed that using of Ferric Chloride achieved less costs in comparison with PACL and Alum (Figures 23-25). Fig. 23: Monthly costs of coagulants injection in WTP of Kut-e Amir. Fig. 24: Monthly costs of coagulants and coagulant aid injection in WTP of Kut-e Amir. Fig. 25: Annual costs of coagulants and coagulant aid injection in WTP of Kut-e Amir. According to the results, costs of Ferric Chloride were less than PACL and Alum in WTP of Kut-e Amir. So, considering close and suitable results of Ferric Chloride and PACL in turbidity removal and more economical efficiency of Ferric Chloride than PACL, it s recommended to be used from Ferric Chloride with Besfloc when initial turbidity be under 6500 NTU. Because under 6500 NTU, there is not any exploitation problem for WTPs. But, according to Figures 19-22, in initial turbidity more than 6500 NTU, the efficiency of

10 1050 Davoud Khodadadi Dehkordi et al, 2014 PACL was better than Ferric Chloride in turbidity removal of Karoun River water and it s recommended to be used form PACL in this conditions and ignore economic aspects. Because, in WTP of Kut-e Amir and in high initial turbidities with efficiency reduction of Ferric Chloride, taking water from Karoun River is cut. In addition, the experiences have confirmed that with a pause in taking water from Karoun River even for one hour, water subscribers in Ahvaz city will have a shortage about m 3. So, it s important to use form PACL with Besfloc in high initial turbidity (more than 6500 NTU) for achieving better results and better turbidity removal. PACL as the most effective coagulant is confirmed by Safaifar et al [15]; Wang et al [26]; Eric and Kara [3]; Luan [7]; Tang and Luan [21]; Malhutra [9] and O Melia et al [11]. Besides, Alum had the least effect on turbidity removal in entire experiments. Maybe Alum be cheaper than PACL but it never have suitable efficiency of turbidity removal in comparison with PACL. In addition, it should be considered that coagulation with Alum may increase aluminum concentration in drinking water as reported in many texts [2]. Aluminum in coagulated drinking water has been regarded as a subject of human and environmental health concern [5]. Driscoll et al [2] observed that the use of Alum could increase the total Al (III) concentration from 0.37±0.33 μmol l 1 in raw water to 1.8±0.33 μmol L 1 in filtered water. Alum human health hazards have been well-documented [1]. -Evaluation of ph variations under coagulants injection: Researches results have indicated that ph is one of the parameters that turbidity removal efficiency changes by it, whereas, Volk et al [22] indicated that the ph of coagulation was the most influential parameter in natural organic matter (NOM) removal from water. According to the results, injection of coagulants different doses (Table 1) did not vary ph of samples significantly and samples ph after injection of coagulants different doses was in standard range (7-8). Figures show ph variations under minimum and maximum doses injection of coagulants respectively. Fig. 26: ph variations under minimum dose injection (1.5 ppm) of coagulants. Fig. 27: ph variations under maximum dose injection (5 ppm) of coagulants. Conclusion: According to the results, PACL and Ferric Chloride had the better results in turbidity removal in comparison with Alum. Considering close and suitable results of Ferric Chloride and PACL in turbidity removal and more economical efficiency of Ferric Chloride than PACL, it s recommended to be used from Ferric Chloride with Besfloc when turbidity be under 6500 NTU. Because the efficiency of PACL was better than

11 1051 Davoud Khodadadi Dehkordi et al, 2014 Ferric Chloride in turbidity removal of Karoun River water in initial turbidity of > 6500 NTU, it s recommended to be used form PACL in this conditions and ignore economic aspects. Otherwise, it causes a pause in taking water from river. In the end, injection of coagulants different doses did not vary ph of samples significantly. REFERENCES [1] Baghvand, A., A. Daryabeigi-Zand, N. Mehrdadi and A. Karbassi, Optimizing coagulation process for low to high turbidity waters using aluminum and iron salts. American Journal of Environmental Sciences, 6(5): [2] Driscoll, C.T., D. Raymond and D. Letterman, Chemistry and fate of Al(III) in treated drinking water. J. Environ. Eng., 114: [3] Eric, H. and H. Kara, Optimizing coagulant conditions for the Worcester water filtration plants. A Major Qualifying Project Report Submitted to the Faculty of Worcester Polytechnic Institute, USA. [4] Gray, K.A., C.H. Yao and C.R. O Melia, American Water Works Association, 87(4): 136. [5] Guida, M., M. Mattei, C. Della, Rocca, G. Melluso and S. Meric, Optimization of alumcoagulation/flocculation for COD and TSS removal from five municipal wastewater. Desalination, 211: [6] Kord-Mostafapoor, F., E. Bazrafshan and H. Kamani, Effectiveness of Three Coagulants of Polyaluminum Chloride, Aluminum Sulfate and Ferric Chloride in Turbidity Removal from Drinking Water. Zahedan Journal of Research in Medical Sciences, 10(2): [7] Luan, Z.K., Theory and application of inorganic polymer flocculant-polyaluminium chloride. Doctoral Dissertation, Research Center for Eco-Enviromental Sciences, Chinese Academy of Sciences, Beijing, [8] Matsui, Y., A. Yuasa, Y. Furuya and T. Kamei, American Water Works Association. 88(10): [9] Malhutra, S., Polyaluminum chloride as an alternative coagulant. Proc. 20th WEDC Conference Colombo, Sri Lanka, [10] Nabi-Bidhendi, G., T. Shahriari and S. Shahriari, Plantago Ovata Efficiency in Elimination of Water Turbidity. Water Resource and Protection. 1(2): [11] O Melia, C.R., K. Gray and C. Yao, Polymeric inorganic coagulants. AWWARF Final Report. Denver, CO: American Water Works Association Research Foundation. [12] Parker, D.R. and P.M. Bersch, Formation of the Al13 tridecameric polycation under diverse synthesis condi-tions. Environment Science Technology, 26: [13] Solomentseva, I.M., N.G. Gerasimenko and S. Barany, Surface properties and aggregation of basic aluminum chloride hydrolysis products, Colloids Surf., A: Physicochem. Eng. Aspects, 151: [14] Sid-Mohammadi, A., G. Zamini, T. Mohammadi and N. Salahshour, Evaluation of Polyaluminum Chloride and Ferric Chloride efficiency in water treatment plant of Sanandaj city. The 9th National Congress on Environmental Health. (In Farsi). [15] Safaifar, M., A. Torabian and A. Rashidi-Mehrabadi, Impact evaluation of coagulant type on operation indices in direct filtration process. The 2th National Conference on Operation and Maintenance of Water and Waste Water Systems, pp: [16] Tang, H.X. and W. Stumm, The Coagulating Behaviors of Fe (III) Polymeric Species, II: Preformed Polymers in Various Concentrations. Water Research, 21(1): [17] Tang, H.X., Basic studies of inorganic polymer flocculants, Environ. Chem. 9(3): 1-12 (In Chinese). [18] Tang, H.X., B.Z. Tian, Z.K. Luan and Y. Zhang, Inorganic polymer flocculant polyferric chloride, its properties, efficiency and production, In Chemical Water and Wastewater treatment, Vol III, eds R. Klute and H. Hahn, Springer, Berlin, pp [19] Tang, H.X., Z.K. Luan, D.S. Wang and B.Y. Gao, Composite inorganic polymer flocculants. Chemical Water and Wastewater Treatment (V), Springer-Verlag, pp: [20] Tang, H.X. and Z.K. Luan, The Differences of Behavior and Coagulating Mechanism between Inorganic Polymer Flocculants and Traditional Coagulants. Chemical Water and Wastewater Treatment (IV), Springer-Verlag, pp: [21] Tang, H.X. and Z.K. Luan, Features and mechanism for coagulation-flocculation processes of polyaluminum chloride. J. Environ. Sci., 7(2): [22] Volk, C., K. Bell, E. Ibrahim, D. Verges, G. Amy and M. Lechevaller, Impact of enhanced and optimized coagulation on removal of organic matter and its biodegradable fraction in drinking water. Water Res., 34: [23] Van Benschoten, J.E. and J.K. Edzwald, Chemical aspects of coagulation using aluminum salts - I. Hydrolytic reactions of alum and polyaluminum chloride. Water Research, 24(12):

12 1052 Davoud Khodadadi Dehkordi et al, 2014 [24] Wang, D.S., H.X. Tang and J. Gregory, Relative importance of charge neutralization and precipitation during coagulation with IPF PACl: effect of sulfate, Environ. Sci. Technol., 36(8): [25] Wang, D.S. and H.X. Tang, Modified inorganic polymer flocculant-pfsi: its preparation, characterization and coagulation behavior, Water Res., 35(14): [26] Wang, D., W. Sun, Y. Xu, H. Tang and J. Gregory, Speciation stability of inorganic polymer flocculant PACl. Colloids and Surfaces A: Physicochem. Eng. Aspects, 243: [27] Yukselen, M.A. and J. Gregory, The effect of rapid mixing on the break-up and re-formation of flocs. J. Chem. Technol. Biot., 79: