INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET)

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1 INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET) International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN ISSN (Print) ISSN (Online) Volume 4, Issue 4, May June 2013, pp IAEME: Journal Impact Factor (2013): (Calculated by GISI) IJARET I A E M E FACTORS AFEECTING THE COAGULATION OF TURBID WATER WITH BLEND COAGULANT MORINGA OLEIFERA & ALUM Dr. S. A. Halkude 1, C. P. Pise 2 1 Professor and Principal, Department of Civil Engineering, Walchand Institute of Technology, Solapur, Maharashtra, India 2 Research Scholar and Assistant Professor, Department of Civil Engineering, SKN Sinhgad College of Engineering Pandharpur, Dist-Solapur, Maharashtra, India ABSTRACT The scope of the present study is optimizing the parameters which affect coagulation of turbid water namely, slow mix velocity gradient, dose of blend coagulant Moringa Oleifera & Alum, basin parameters with different initial turbidity water samples. Initially these parameters are varied randomly, while keeping all other parameters constant for carrying out optimization. Optimum dose for removal turbidity using blend coagulant required for the different initial turbid water samples (e.g, 150 NTU, 300 NTU and 500 NTU), is found out. While other parameters like jar configurations, velocity gradient, slow mixing time, settlement time are kept constant. Dose of coagulant which is found to be optimum during the initial study is used in the all the testing. Results are analyzed by preparing the graphs of Dose versus Residual turbidity. Effect of various jar configurations such as Circular Non Baffled Jar (CNBJ), Circular Baffled Jar (CBJ), Square Non Baffled Jar (SNBJ) and Square Baffled Jar (SBJ) is studied, while all other parameters are kept constant. The dose of coagulant is again optimized with respect to Jar Configurations by observing the effect of different Jar Configurations and results are analyzed. Also the study for different velocity gradients like 40 s -1, 65 s -1 and 90 s -1 is carried out, while other parameters are kept constant except SBJ and CBJ, which are found most influential. Results are analyzed & presented in the graphs between residual turbidity versus velocity gradient. KEYWORDS: Blended coagulant, Moringa Oleifera, Optimization, coagulation, velocity gradient, Basin Parameter. 181

2 INTRODUCTION Ability of Moringa oleifera in the removal of many contaminants from water effluents is well known since long time. [1, 2]. As a tropical multipurpose tree, M. oleifera is commonly known as the miracle tree [3] because of its wide variety of benefits that cover from nutritional issues [4] to cosmetics [5]. Among many other properties, Moringa oleifera seeds contain a coagulant protein to be used either in drinking water clarification [6] or wastewater treatment [7]. It is said to be one of the most effective natural coagulants and the investigation on these kinds of water treatment agents is growing day by day [8]. The raw origin of this coagulant makes its speciation difficult; however researchers have identified the coagulant component from M. oleifera seed extract as a cationic protein [9,10] is in general agreement in considering it as formed of that dimeric proteins with a molecular weight in the range of k Da. The use of Moringa Oleifera as a coagulant is full of advantages, when compared with traditional alum or ferric salts [11]. The drawbacks of chemical coagulants is well known, there is a need to develop alternative, cost effective and environmentally friendly coagulants. A number of effective coagulants from plant origin have been identified: Nirmali [12]; Okra [13]; red bean, sugar and red maize [14], Moringa oleifera [15], and a natural coagulant from animal origin; chitosan. Natural mineral coagulants have also been used including fluvial clays and earth from termite hills. Of all plant material investigated, it is observed that seeds of Moringa Oleifera are one of the most effective sources of coagulant for water treatment. In laboratory and field tests, seed of Moringa Oleifera have shown promise as a coagulant in the clarification of turbid water [16, 17, and 18]. The seeds contain water soluble positively charged proteins that act as an effective coagulant however the crude moringa extract (though efficient in removal of turbidity) increased the organic load in the treated water [19]. Moringa Oleifera as natural coagulant is reported to have many advantages over chemical coagulant e.g. Alum. Use of chemical coagulant has constrains of ph and alkalinity. However, Moringa Oleifera has been reported to be free of these constraints. Sludge product with Moringa Oleifera is reported to be four to five times compact than that produced with alum. Turbidity removal can be achieved with Moringa Oleifera. The use of Moringa Oleifera as a coagulant is mostly used in water treatment that too on small scale and major work has been reported in laboratory scale water treatment that too on small scale. The Moringa oleifera is not used in field because of the some drawbacks of Moringa oleifera as it requires large amounts of seeds for small water treatment plant. Also, the settling time is more. If the blended coagulant of Moringa oleifera & alum is used then the drawbacks of alum and moringa oleifera is reduced and this blend coagulant gives best results. [20, 21] The investigations carried out using the conventional jar test have been used to evaluate the coordination efficiency of Moringa Oleifera in the treatment of surface waters & synthetic waters. At present, in most of such studies the physical parameters like slow mixing velocity gradient & time, rapid mixing velocity gradient & time are determined according to standard jar test values for alum coagulation. The only parameter varied in most of the cases is dose of blend of Moringa Oleifera & alum. Further more studies into the interaction between physical parameters affecting coagulation like slow mix, rapid mix rates & time is not studied. In this study laboratory investigation is carried out to determine the multiple effects of physical parameters of slow mixing grades & dose of coagulant & basin parameters & initial 182

3 particulate concentration (turbidity) on coagulation of turbid water with blend of Moringa Oleifera & alum. The three parameters slow mix velocity gradient, doses of blend coagulant Moringa Oleifera & alum, and basin parameters. These three parameters are varied, while keeping other parameters constant & study is carried out for arriving at an optimum dose of Moringa Oleifera & alum. MATERIALS AND METHODS Preparation of Seed Extracts: Tree dried Moringa Oleifera seeds are procured from local trees. Good quality seeds are then picked up and crushed to fine powder. Then 5 gm of seed powder is mixed with 500 ml distilled water for 2 minutes. Then mixture is kept for 2 mins. Again mixture is stirred for 1 min. Then, mixture is filtered through Muslin Cloth. Filtrate is diluted by distilled water to make it up to 500 ml. Resulting stock solution is having approximate concentration of mg/l (1%). Fresh stock solutions are prepared every day for the one day s experimental run. Preparation of 1% Alum Solution: 1 gm of the Alum is mixed with 100 ml of distilled water. This mixture is stirred for 5 minutes so that all the Alum powder is soluble into the distilled water. This Alum solution is of 1 % concentration. When the Alum is added to the turbid sample the acidity is increased. For neutralizing the induced acidity by Alum, 1% Lime dose is added with it. Also this Lime doses helps in ph correction. Preparation of 1% Lime Solution: 1 gm of the Lime is mixed with 100 ml of distilled water. This mixture is stirred for 5 minutes so that all the Lime powder is soluble into the distilled water. This Lime solution is of 1 % concentration. For finding the doses of the Alum using the jar test the following doses of Alum and Lime solution, should be added into the sample. Preparation of Moringa Oleifera & Alum Solution: Moringa Oleifera & Alum Solution are prepared separately and entered separately with Alum first and Moringa Oleifera a couple of seconds later. But, for preparation of blend coagulant the optimum dosage found for different initial turbidity samples are taken as base line and different proportions of alum and Moringa Oleifera are tested for removing the turbidity from jar test, then it is observed that for 150 NTU initial turbidity, the optimum dose of the Alum is reduced to 75 % and the optimum dose of the Moringa Oleifera is reduced to 40 % then this blended coagulant gives the minimum residual turbidity. Similarly for 300 NTU & 500 NTU initial turbidity, the optimum dose of the Alum is reduced to 62.5 % and the optimum dose of the Moringa Oleifera is reduced to 25 % then this blended coagulant gives the minimum residual turbidity. Preparation of turbid water sample: 5gm of kaolin clay is mixed to 500 ml distilled water. Mixed clay sample is allowed for soaking for 24 hrs. Suspension is then stirred in the rapid stirrer so as to achieve uniform and homogeneous sample. Resulting suspension is found to be colloidal and used as stock solution for preparation of turbid water samples. Everyday stock sample of kaolin clay is diluted to tap water to desired turbidity. 183

4 EXPERIMENTATION METHOD Mainly the scope of the work is to deal with the slow mixing parameters which affect the effective floc formation and settlement characteristics of the turbid water. Entire work comprises of three stages, viz. Optimum dose determination, effect of different jar parameter and effect of different velocity gradient of slow mixing, at the same time, rapid mixing procedure is kept constant throughout all the experimental runs. Entire work is divided into three different stages. In each stage one variable is changed while others are kept constant. In all the stages, rapid mixing is done at approximately 120 rpm for the time interval of 2 minutes so as to achieve uniform dispersion of coagulant. Optimum dose determination: The optimum dose required for the different initial turbidities like, 150 NTU, 300 NTU and 500 NTU dealt while other parameters like jar configurations, velocity gradient, slow mixing time, settlement time are kept constant for all the initial turbidity ranges. Dose of Blend coagulant which is found to be optimum is used in the all the testing. Results are analyzed by preparing the graphs between Doses versus respective Residual turbidity. Effect of different jar parameter: The effect of different jar configuration like SBJ, SNBJ, CNBJ, and CBJ while other parameters like, slow mixing time and velocity gradient, settling time are kept constant. In this Part dosage of coagulant is again optimized with respect to different Jar Configurations and effect of different Jar Configurations is tested. In this Part results are analyzed by working out the variations in the residual turbidity with respect to Jar Configurations which is reflected in the graphs. Effect of different velocity gradient: Effect of different velocity gradients like 40 s -1, 65 s -1 and 90 s -1 while other parameters like jars, slow mixing time, settling time are kept constant. SBJ and CBJ are used as they are found to be most effective during the trial. Results are analyzed by preparing the graphs between residual turbidity versus velocity gradient. Table -1 show different types of jars used in the experiment with their dimensions and figures Table- 2 shows various physical parameters considered in the experiment and Table - 3 shows the optimum dose of blend coagulant for different initial turbidity samples. 184

5 Table 1: Types of Jars Sr. Type of jar Dimensions (Internal) Photo No. of jars 1. Square Baffled Jar (SBJ) 2. Square Nonbaffled Jar (SNBJ) 10 cm (L) 10 cm (B) 16 cm(h) With 4 baffles(one on each side) of 1.2 cm 0.2 cm all along the height 10cm(L) 10 cm (B) 16 cm(h) Circular Non- Baffled Jar (CNBJ) 12 cm (dia) 16 cm (H) 3 4. Circular Baffled Jar (CBJ) 12 cm (dia) 16 cm (H) With 4 baffles(one at each quadrant point) of 1.2 cm 0.2 cm all along the height 3 Procedure Followed For Determination of Velocity Gradient (G): Where, G = P V µ µ = Viscosity (N.s/m 2 ) P = Power input (N.m/s) V = Volume of mixing basin (m 3 ). (1) Where, Where, P = D x V p (2) D = Drag force on paddles (N) v p = Velocity of paddles (m/s) 2 (C D A p ρ V p ) D = 2 C D = co-efficient drag, 1.8 for flat blades. A P = Area of paddles (m 2 ) ρ = Density of water (kg/ m 3 ) (3) 185

6 Where, V = p ( π D N) 60 N = r.p.m. (No.) D = Diameter of blades (m) (4) Table 2: Physical Parameters with 150, 300, 500 NTU initial turbidity Sr Physical Parameters Remark 1 Initial Turbidity 150, 300, Concentration of coagulant 1 % 3 Slow mix velocity 30 rpm 4 Slow mixing time 30 mins 5 Rapid mix velocity 120 rpm 6 Rapid mixing time 2 mins 7 Settling time 30 mins Sr Table 3: Optimum Dose of Alum & M.O. Turbidity in NTU Dose mg/l Residual turbidity Average 25, , , , , , , , , RESIDUAL TURBIDITY GRAPH -1 OPTIMUM DOSE OF M.O. & ALUM 25, , 75 10, ,125 20, , , , , NTU 300 NTU 500 NTU DOSE & INITIAL TURBIDITY SET 1 SET 2 186

7 RESUIDUAL TURBIDITY GRAPH -2 EFFECT OF JAR PARAMETER CNBJ CBJ SNBJ SBJ TYPES OF JARS 150 NTU 300 NTU 500 NTU RESIDUAL TURBIDITY GRAPH -3 EFFECT OF JARS WITH OPTIMUM DOSE 20, mg/l CNBJ CBJ SNBJ SBJ TYPES OF JARS 150 NTU 300 NTU 500 NTU GRAPH -4 EFFECT OF SLOW MIX VELOCITY GRADIENT 30 RESIDUAL TURBIDITY SBJ CBJ SBJ CBJ SBJ CBJ 40 s-1 65 s-1 90 s NTU 300 NTU 500 NTU TYPES OF JAR & TURBIDITY 187

8 100 GRAPH -5 TURBIDITY REMOVAL EFFICIENCY (%) REMOVAL EFFICIENCY SBJ CBJ SBJ CBJ SBJ CBJ 40 s-1 65 s-1 90 s-1 SLOW MIX VELOCITY GRADIENT & JARS 150 NTU 300 NTU 500 NTU RESULTS AND DISCUSSION From the Graph-1, the optimum dose of the blended coagulant for initial turbidity 150 NTU is Alum mg/lit, M.O. 75 mg/lit. For initial turbidity 300 NTU the optimum dose of the blended coagulant is Alum 20 mg/lit, M.O mg/lit. For initial turbidity 500 NTU the optimum dose of the blended coagulant is Alum - 30 mg/lit, M.O mg/lit. From Graph-2, it is found that optimum dose of blend coagulant required for almost all the initial turbidity in between 150 NTU and 500 NTU is 20 mg/lit for Alum & 100 mg/lit for M.O. At this blend dose (Alum 20 mg/lit, + M.O mg/lit) floc formation and particle settling is highest for CBJ jars. This value of optimum dose is higher as compared to other studies reported. Further increase of coagulant dose, it is observed that Residual turbidity increase with increasing dose. However, further increase in blend coagulant dose shows marginal increase in the residual turbidity. Turbidity removal efficiency, in the case of 150 NTU initial turbidity is 95.5%, for 300 NTU initial turbidity, it is 95.35% and for 500 NTU initial turbidity, it is 96.5%. This clearly indicates that increase in the initial turbidity increases the turbidity removal efficiency. This observation can be explained in terms of the increase in suspended particles available for adsorption and inter-particle bridge formation. The effect of jar parameters, (CBJ, CNBJ, SBJ, SNBJ), with respect to different initial turbidities is shown by Graph -3. It is seen from the Graph. 2 that SBJ and CBJ are giving less residual turbidities as compared to their non-baffled counter parts. Baffled jars are showing approximately 10 % more turbidity removal than the non-baffled jars of respective types. More turbidity removal in case of Baffled jars is due to vortex formation. This is due to introduction baffles leading centrifugal forces. These centrifugal forces make them to move outwards and may make particle to settle down. Second likely reason, the more inter particle collision because of turbulence created by baffles, leading to higher rate of agglomeration. All above discussion leads to a conclusion that baffled jars give higher rate of agglomeration, resulting into higher turbidity removal. The Graph-4 shows the effect of slow mix velocity gradient with water sample of initial turbidity 150 NTU, 300 NTU and 500 NTU. From this graph, it is observed that the optimum velocity gradient is 65 s

9 It is observed that the all parameters which affect the coagulation activity which are optimum in earlier experiment shows maximum removal efficiency refers Graph -5. From the graph-5, it is observed that at slow mix velocity gradient 65 s -1 at which the removal efficiency for SBJ and CBJ is maximum. The removal efficiency for SBJ for 150 NTU, 300NTU & 500NTU turbidity is 95.2, 96.9, and 97.9 respectively.the removal efficiency for CBJ for 150 NTU, 300NTU & 500 NTU turbidity is 95, 95.8, and 96 respectively. CONCLUSIONS The coagulation of turbid water is influenced by various parameters such as slow mix velocity gradient, dose of Blend coagulant Moringa Oleifera (M.O.) & Alum, the basin Parameters, and initial turbid of water samples. The optimum dose of blended coagulant for initial turbidity 150 NTU is Alum mg/lit, M.O. 75 mg/lit. For initial turbidity 300 NTU the dose is Alum 20 mg/lit, M.O mg/lit and for 500 NTU the optimum dose is Alum - 30 mg/lit, M.O mg/lit. The efficent jar configuration found is Circular Baffled Jar (CBJ) and Square Baffled Jar (SBJ), which are producing less residual turbidity as compared to non-baffled Jars. Baffled jars are showing 10 % more turbidity removal efficiency with respect to non-baffled jars., The optimum dose of coagulant is observed to be same for various Jar Configurations, which is 20 mg/lit for Alum, 100 mg/lit for M.O. The optimum slow mix velocity gradient is 65 s -1 at which the turbidity removal efficiency for SBJ & CBJ is maximum. REFERENCES 1. A. Olsen (1987), Low technology water purification by bentonite clay Moringa oleifera seed flocculation as performed in Sudanese villages: effects on Schistosoma mansoni cercariae, Water Research 21 (5) B. Bolto, J. Gregory (2007), Organic polyelectrolytes in water treatment, Water Research 41 (11) L.J. Fuglie (2001), the Miracle Tree. The Multiple Attributes of Moringa, Technical Centre for Agricultural and Rural Cooperation. 4. H.P.S. Makkar, K. Becker (1996), Nutritional value and anti-nutritional components of whole and ethanol extracted Moringa oleifera leaves, Animal Feed Science and Technology 63(1) I. Armand-Stussi, V. Basocak, G. Pauly, J. McCaulley (2003), Moringa oleifera: an interesting source of active ingredients for skin and hair care, SOFW-Journal 129 (9) A. Ndabigengesere, K.S. Narasiah, B.G. Talbot (1995), Active agents and mechanism of coagulation of turbid waters using Moringa oleifera, Water Research 29 (2) A. Ndabigengesere, K.S. Narasiah (1998), Use of Moringa oleifera seeds as a primary coagulant in wastewater treatment, Environmental Technology 19 (8) M. Sciban, M. Klasnja, M. Antov, B. Skrbic (2009), Removal of water turbidity by natural coagulants obtained from chestnut and acorn, Bioresource Technology 100 (24) U. Gassenschmidt, K.D. Jany, B. Tauscher, H. Niebergall (1995), Isolation and characterization of a flocculating protein from Moringa oleifera lam, Biochimicaet Biophysica Acta 1243 (3)

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