Effect of Mixing Natural Coagulant with Alum on Water Treatment

The 3rd National Graduate Conference (NatGrad2015), Universiti Tenaga Nasional, Putrajaya Campus, 8-9 April 2015.

Effect of Mixing Natural Coagulant with Alum on Water Treatment Gasim Hayder College of Engineering, Universiti Tenaga Nasional, Malaysia. Email: [email protected] Asmah Ab Rahim College of Engineering, Universiti Tenaga Nasional, Malaysia. Email: [email protected]

Abstract— Coagulation chemicals such as Aluminium are widely used in water treatment. Water treatment using chemicals can be very costly and the use of high level of alum in water can caused hazard disease like Alzheimer. As an alternative, coagulant from natural substance (i.e. Dolichos Lablab) mix with alum is used for coagulation in water treatment. It is more environmental friendly and effective in term of cost. The use of natural coagulant can reduce the dosage of alum in water treatment. This research aims to analyse the effect of mixing different types of natural coagulant with alum and which will give the better result in turbidity removal at its optimum mixing ratio. Natural coagulant mixes with alum were added to the jars containing one litre of raw water were compared to a jar containing raw water added with Alum only which acted as a reference. Different ratios (1:1 and 1:2) of natural coagulant to alum were prepared. Turbidity and colour were measured and the results obtained were evaluated. It was found that by using the ratio of alum to Dolichos Lablab of 1:2 has better turbidity removal of 71.27% from 2200 NTU to 632 NTU of 5 ml/L respectively for the synthetic water. As for lake water, it is shown that the mixture of alum to dolichos lablab at ratio 1:1 and 6:6 ml/L has highest turbidity removal of 95.51% from 12.8 NTU to 0.575 NTU. Keywords—coagulant aid; Alum; water treatment; turbid water; jar test.

I.

INTRODUCTION

This Water treatment is vital to deliver safe water for drinking and cleaning to the whole population. Purification of water for use is critical as they have immediate impact to human wellbeing. Contaminated water is full with sickness making microorganisms and this helps waterborne diseases [1]. The process in water treatment involved raw water to be pumped to the treatment plant and flow through the aerator. Primary coagulant, poly aluminum chloride (PACI) was added into the chamber to enhance the flocs formation removal in the clarification process. Next, the water is filtered to remove fine particles and finally the treated water will be distributed to the user after disinfection and pH correction. Coagulation/flocculation is an important process in water treatment. Coagulation/flocculation is the process of binding small particles in the water into larger particles. Heavier particles will settle relatively quickly compared to small particles. The larger particles are known as flocs. Mostly in water treatment, chemical coagulant is used to remove turbidity before the water can be consumed by the

users. The used chemicals for water treatment often are inorganic substances such as aluminum. Aluminum can be costly as they are needed in a large amount for water treatment and it associated with human health and can affect the environment. The jar test is a common laboratory testing used to determine the optimum dosage requirement for chemicals added to remove suspended particles in water sample. This method permits adjustments in pH value of water, variety in sorts of coagulant utilized, testing different coagulant dose or alternating mixing speeds. A jar test simulates the coagulation and flocculation processes that encourage the removal of suspended colloids and organic matters, which can prompt to turbidity, odor and taste problems. Jar test involve slow mixing and rapid mixing. During rapid mixing, the coagulant is quickly mixed with water to create efficient and effective conditions for water treatment. In slow mixing, the mixture is stirred to encourage the particles to clump together to form flocs so that the flocs can settle faster. Slow mixing is required so that the flocs form will not break. There have been many research published of using natural coagulant to replace aluminum for water treatment. Some of natural coagulant utilized are Guar Gum (Cyamopsis Tetragonolobus), Mallow powdered, Okra powdered, Moringa Oleifera, Arabic Gum, and Hyacinth Bean (Dolichos Lablab). They have demonstrated remarkably positive reduction in turbidity removal by using the natural coagulant alone. It is important to study and understand the existing researches related to this project to widen the view and achieve the optimum results on the work proposed. In coagulation, a coagulant (generally positive charges) is added to neutralize the electrostatic surface of the potential particle. This will result in the destabilized of the particles to stick together to form flocs. Developing countries adopted the use of natural polymers for water treatment over chemicals as the natural coagulants give a lot of benefits to human health and reduce hazard to the environment from the use of aluminum for production of treated water. Practically, many research involving Dolichos Lablab as natural coagulant. The results show high percentage of turbidity removal. Shwetha L and Usha N Murthy [2] result demonstrates that optimum dosage for Dolichos Lablab was found to be 20 mg/L at the optimum mixing speed of 200 rpm. They compared six different natural coagulant namely Moringa Oleifera, seed coat of Hyacinth Bean, leaves of Calotropis procera, leaves of Solanum inacunum, peels of Hyacinth Bean and leaves of Neem. Based on the experiment carried out, it was said to be Moringa oleifera and seed coat of Hyacinth bean

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shows high percentage of turbidity removal of 85.2% and 84% from 100 NTU to 14.8 NTU and from 100 NTU to 16 NTU respectively for dose of 50mg/L used. Unnisa et al. [1] reported that using Dolichos Lablab as natural coagulant with solar disinfection gave significantly high reduction in turbidity removal for different turbidity of water samples and further reduce the bacteria growth in the water samples. At high water turbid, 68% of coagulation activity had achieved and 65% and 62% of coagulation activity for low and medium water tubid respectively. The Dolichos Lablab works at its best at the dose of 200mg/500mL at 60 minutes settling time. Dolichos Lablab seed powder at its optimum concentration does not affect the pH and alkalinity of water. Dolichos Lablab performs best with the finest grain size to further reduce the turbidity of water. Choubey et al. [3] uses Moringa oleifera, Cicer arietinum, and Dolichos lablab as natural coagulant for water treatment. Based on the result, for high turbid of water with 50mg/L dose used, 87.3% removal from 100 NTU to 11.8 NTU for Moringa oleifera. For Cicer arietinum, 92.8% of turbidity reduced from 95 NTU to 6.2 NTU and for Dolichos Lablab, the turbidity reduced from 100 NTU to 15.8 NTU for 84.7% removal. It was said that, Moringa oleifera and Cicer arietinum show high percentage turbidity removal of all three. Moringa seed is nontoxic and good to use for coagulant in water treatment. The result shows even greater reduction after filtration. A study led by Md. Asrafuzzaman et al. [4] also uses Moringa oleifera, Cicer arietinum and Dolichos lablab as natural coagulants for water treatment. For 50mg/L of Moringa oleifera, the turbidity removal is 86.9% from 100 NTU to 13.1 NTU. For Dolichos lablab, the percentage removal is 86.9% from 100 NTU to 15.5 NTU at 50mg/L dose of Dolichos lablab solution. As for Cicer arietinum, at 50mg/L of dosage, the turbidity removed is 93.8% from 95 NTU to 5.9 NTU. The turbidity reduction shows greater result for high turbid of water. The turbidity was further reduced after filtration. B. S. Shilpa et al. [5] investigate the effect of Cactus and Hyacinth bean peels as natural coagulants for water treatment. The study concludes that the optimum dosage for Cactus and Hyacinth bean in both synthetic water and water sample is to be 20mg/L. Both natural coagulants shows turbidity removal efficiency to be 89.03% and 77.10% for Cactus and Hyacinth bean peels respectively. Dolichos lablab demonstrates best performance in high turbidity of water, which the removal in 68% is observed. From the study, it can be deduce that the use of natural coagulant had caught in attention for their effectiveness in water treatment. The technologies involved the uses of natural coagulants are economical, easy to implement and can reduced waterborne diseases from the usage of chemical coagulant for water treatment. In the other hand, coagulation studies using natural coagulant proved the use of coagulant aid with alum to cause the flocs to form faster and increase the rate of sedimentation. Natural coagulant appears to show efficient removal at higher turbidity. The usage of natural coagulant can lessen nearly 15% to 30% of alum used in water treatment [6]. Quick populace development and expanding industrialization action have expanded the interest for fresh treated water. For quick treated water generation, they utilize Aluminum salt as synthetic coagulant for water treatment. Aluminum salt at its ideal pH

and dose, decrease the natural matter, color, and turbidity [7]. It has been affirmed that Aluminum exposures help in advancement of Alzheimer disease in people [7]. In this manner, the challenge is to decrease the measurement of Aluminum salt utilized as a part of water treatment and being able to bring down the danger of hazard disease. The aim of the present study focuses on Hyacinth Bean (Dolichos Lablab) mixes with Aluminum as natural treatment methods to reduce the measurement of Aluminum used during coagulation process and the required mixing ratio between natural coagulant and aluminum to achieve optimum removal. This was accomplished by introducing natural coagulant and mix with aluminum to lessen the dosage of aluminum used in water treatment. Compare different mixing ratio of natural coagulant to aluminum (1:1, and 1:2) and which will give the optimum mixing ratio. Determine the viability of mixing natural coagulant with aluminum for water treatment in term of turbidity removal. Conducts jar test and measure color and turbidity. II.

METHODOLOGY

This project focuses on mixing natural coagulant with alum so that the dosage of alum use in water treatment can be reduced and lessen the possibilities of hazard diseases by alum. The treatment cost likewise can be cut down, as the dose of alum use is less than usual. The natural coagulant use only concentrates on Dolichos Lablab. Yet, few researches have been carried out using Dolichos Lablab mixed with alum as natural coagulant for water treatment. In this project, different mixing ratio of natural coagulant and alum is use to set the optimum ratio of natural coagulant to alum. Ratio of 1:1 and 1:2 of natural coagulant to alum is mix to see which mixing ratio is the most ideal. Coagulation/flocculation is the process of binding small particles in the water together into larger clumps called floc to settle. The jar test experiment was conducted for different mixing ratio of natural coagulant and alum to attain optimal coagulation. Colour and turbidity were measured using spectrophotometer and turbidity meter respectively. A. Using Lake Water The experiment was conducted on a sample collected from nearby lake. Alum (A) was used together with either Polymer (PO) or with natural coagulant (NC) Dolichos Lablab or with both as shown in Table 1. TABLE I. Run 1 2 3 4

A PO A NC A NC A PO NC

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THE EXPERIMENT DETAILS FOR LAKE WATER. Jar 1

Jar 2

Jar 3

1 1 1 1 1 2 1 0.5 0.5

2 2 2 2 2 4 2 1 1

3 3 3 3 3 6 3 1.5 1.5

Jar 4 mL 4 4 4 4 4 8 4 2 2

Jar 5

Jar 6

5 5 5 5 5 10 5 2.5 2.5

6 6 6 6 6 12 6 3 3

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B. Using Synthetic Water The The experiment was conducted on a sample prepared in the lab from tab water mixed with fine mud. Alum and natural coagulant Dolichos Lablab were used as shown in Table 2. TABLE II. Run 1 2 3 4

A NC A NC A NC

THE EXPERIMENT DETAILS FOR SYNTHETIC WATER. Jar 1

Jar 2

Jar 3

2 2 1 4 2

3 3 1.5 1.5 1 2

4 4 2 2 1.3 2.7

III.

Jar 4 mL 5 5 2.5 2.5 1.7 3.3

Jar 5

Jar 6

6 6 3 3 2 4

7 7 3.5 3.5 2.3 4.7

RESULTS AND ANALYSIS

A. Using Lake Water: Turbidity Results The Fig. 1 shows the effect of mixing alum with polymer, alum with dolichos lablab at ratio 1:1 and 1:2, and a mixture of alum to polymer to dolichos lablab at ratio 1:0.5:0.5. Based on the result, we can compare between the mixtures of alum to polymer with the mixture of alum to dolichos lablab.

Fig. 2. Colour measurement of a mixture of alum with dolichos lablab or/and polymer on lake water.

C. Using Synthetic Water: Turbidity Results Alum as coagulant is used as a control and compared to the other result by the natural coagulant. Fig. 3 indicated the result of turbidity removal with the use of alum as coagulant. The result shows that the lower level of turbidity 229, 321 and 429 NTU from 2200 NTU were produced when 5, 6 and 7 ml/L of alum were used respectively at 60 minutes settling time. Fig. 3 also shows the result of using Dolichos Lablab alone for water treatment. The used of 2 ml/L and 3ml/L of Dolichos Lablab remove turbidity of 2200 NTU to 676 and 766 NTU respectively. Based on the presented result, this indicates that the use of Dolichos Lablab as natural coagulant for water treatment is genuine in a dose of 2 ml/L at a 60 minutes settling time.

Fig. 1. Effect of a mixture of alum with dolichos lablab or/and polymer on turbidity of lake water.

It is shown that the mixture of alum to dolichos lablab at ratio 1:1 has highest turbidity removal of 12.9, 3.46, 2.92, 2.25, 2.05 and 0.575 NTU from 12.8 NTU when compare with the mixture of alum to polymer at ratio 1:1 with turbidity removal of 9.96, 3.12, 3.12, 2.53, 2.31 and 2.44 NTU from 12.8 NTU. The mixture of alum to polymer to dolichos lablab at ratio 1:0.5:0.5 shows turbidity removal of 12.9, 6.31, 7.55, 10.6, 16.9 and 12.6 NTU from 12.8 NTU. As for the mixture of alum to dolichos lablab at ratio of 1:2 the turbidity removal are 14.1, 8.11, 8.02, 6.70, 4.33 and 2.04 NTU. B. Using Lake Water: Colour Results Fig. 2 indicates the colour measurement for the mixture of alum to polymer, mixture of alum to dolichos lablab at ratio 1:1, 1:2 and mixture of alum to polymer to dolichos lablab at ratio 1:0.5:0.5 respectively.

Fig. 3. Effect of alum and dolichos lablab on turbidity of synthetic water.

Fig. 4 demonstrates the high turbidity removal produced when ratio of 1:1 and 1:2 are mixed and give 809 and 632 NTU reduced from 2200 NTU. This clearly shows that the mixture of alum with Dolichos Lablab as natural coagulant gives better result in turbidity removal. The effectiveness of the mixture may be attainable from the increasing number of positive charges from the alum and Dolichos Lablab to form flocs for fast settling.

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Fig. 4. Effect of a mixture of alum and dolichos lablab with ratio 1:1 and 1:2 on turbidity of synthetic water.

D. Using Synthetic Water: Colour Results Fig. 5 shows the colour measurement from the alum. With 5 mL of alum there was good results of clear water. It also shows the colour measurement from the dolichos lablab without alum addition. 2 mL of NC resulted in relatively low colour, but as the dose increases the results were not satisfactory.

Fig. 6. Colour measurement of alum to dolichos lablab on synthetic water at ratio 1:1 and 1:2.

IV.

CONCLUSION

After The usage of Dolichos Lablab with alum shows high efficiency of removing turbidity from the synthetic water and lake water. Therefore, it can be concluded that Dolichos Lablab can be used as natural coagulant with alum in water treatment. Thus, the dosage of alum used originally for treatment can be reduced and further decrease the cost. The use of this approach overall can provides solution to the need for clean water without being exposed to potential health hazard.

ACKNOWLEDGMENT The authors would like to express their gratitude to the Universiti Tenaga Nasional for supporting this research.

REFERENCES [1]

[2] Fig. 5. Colour measurement of alum and dolichos lablab on synthetic water.

Fig. 6 shows the colour measurement from the mixture of alum to dolichos lablab on different ratio 1:1 and 1:2. The trend was not clear on the optimum dosage, but in general the higher dosage of NC with 1:2 ratio achieved better result.

[3]

[4]

[5]

[6]

[7]

S. Azeem Unnisa, Punam Deepthi, Khagga Mukkanti, Efficiency studies with Dolichos Lablab and solar disinfection for treating turbid waters, J Environ Prot Sci 4 (2010) 8-12. L. Shwetha, U. N. Murthy, Evaluation of Coagulation Potential of Six Different Natural Coagulants in Water Treatment, Res Rev: J Eng Technol 2.3 (2013) 238-243. S. Choubey, S. K. Rajput, K. N. Bapat, Comparison of Efficiency of some Natural Coagulants-Bioremediation, Int J of Emerging Technology and Advanced Engineering 2.10 (2012) 429-434. M. Asrafuzzaman, A. N. M. Fakhruddin, M. Alamgir Hossain, Reduction of Turbidity of Water Using Locally Available Natural Coagulants, ISRN Microbiology 1 (2011) 1-6. B. S. Shilpa, Akanksha, Kavita, and P. Girish, Evaluation of Cactus and Hyacinth Bean Peels as Natural Coagulants, Int J of Chemical and Environmental Engineering 3.3 (2012) 187-191. A. H. Sulaymon, M. Y. Abdul-Ahad, R. A. Mahmood, Removal of Water Turbidity by Different Coagulants, J of Engineering 19.12 (2013) 1566-1575. World Health Organization. Guidelines for drinking-water quality: First addendum to volume 1, Recommendations: Aluminium in Drinking Water, Vol. 1, Geneva, 2006.

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