PERFORMANCE EVALUATION OF SAND AND CHITOSAN AS DUAL FILTER MEDIA

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PERFORMANCE EVALUATION OF

SAND AND CHITOSAN AS

DUAL FILTER MEDIA

MADHUKAR M*1., Dr. H. S. DAYANANDA2., CHETHAN G3., DWITHIYA C., CHAITHRA K. R., SAJINI B., SANDEEP S.

1 & 3

Asst. Professor, Department of Environmental Engineering,

2_{Professor and Head, Department of Environmental Engineering,}

Vidyavardhaka College of Engineering, Mysore, Karnataka 570 002, India. *Corresponding author: madhu3210@gmail.com

Abstract

Nuisance due to suspended and colloidal particles causing turbidity has become widespread, severe problem due to urban population and industrial activities. The consequences of turbidity are presence of microorganisms, reduction of dissolved oxygen, etc. Consumption of such water is known to cause water borne diseases. Available water treatment methods for the removal of turbidity and pathogens are coagulation, filtration and disinfection. The common filter media used are sand, activated carbon etc. Chitosan has been used as a coagulant aid and adsorbent. Chitosan when used as a filter media causes the colloidal particles to bind together and is subsequently removed during the process. The column studies using Chitosan in combination with conventional sand filter was carried out in a borosilicate glass column. Chitosan was placed on top of sand layer and constant down flow pattern of 100mL/min was followed. Dual filter media was effective in the reducing turbidity by 93%.

Keywords: Turbidity, Chitosan, Sand, Filter.

1. Introduction

Nuisance due to suspended, colloidal particles and micro-organisms causing turbidity has become a widespread and severe problem due to urban population and rapidly increasing industrial activities. Turbidity in water mainly affects the aesthetic conditions. The consequences of turbidity are warmer water, reduced oxygen concentration, decrease in photosynthetic activity of plants etc. Another increasing problem is the presence of pathogenic organisms (Coliform groups) in water. Consumption of such water is known to cause water borne diseases. Nitrate, in particular, causes outbreaks of infectious diseases such as cancer of the alimentary canal and cyanosis among children [Abbas Afkhami, (2003)]. Excess nitrate in drinking water may cause blue-baby syndrome, which results from the conversion of haemoglobin into methaemoglobin, which cannot carry oxygen [P. J. Golden and R. Weinstein, (1998)]. Conventional water treatment methods available for the removal of turbidity and pathogens are coagulation, filtration and disinfection. Filtration is commonly the mechanical or physical operation which is used for the separation of solids from liquids by interposing a medium through which only the liquid can pass. Oversize solids in the liquids are retained, but the separation is not complete; solids will be contaminated with some liquid and filtrate will contain fine particles (depending on the pore size and filter thickness). Chitosan, a natural linear bio poly-amino-saccharide, obtained by the alkaline de-acetylation of chitin is derived from the cell wall of fungi, crustacean exoskeletons, cuticles of insects and some algae [Shahidi F., et al._{(1999)]. Chitosan is known to have various properties; it is known to be non-toxic,}

bio-adhesive and anti-bacterial and is also known to be bio-degradable [Md. Monarul Islama, et al._(2011)].

Chitosan has gained importance in biomedical and environmental biotechnology due to its very high adsorption capacity [H. Yoshida and T. Takemori, (1997), L. Jin and R. Bai, (2002), S. Chatterjee, et al._{(2003), S.}

Chatterjee, et al._{(2007), and W. S. Wan Ngah,}et al._{(2002)]. Recent research has focused on the possibility of}

developing chitosan as a natural disinfectant [Kim C. H., et al_{. (1997)]. Chitosan is a natural disinfectant against}

waterborne pathogens and it is proven to be promising [Chen Y. M., et al._{(2002)]. The common filter media}

being used for filtration are sand, anthracite, activated carbon, etc. These filter media, though effective in filtering, have various disadvantages. Chitosan due to its advantageous properties it is being considered as alternatives to the common filter media, as it not only filters water effectively, but also adds to beneficial characteristics, rendering water safe and beneficial for consumption. In recent days, owing to the increasing Madhukar M et al. / International Journal of Engineering Science and Technology (IJEST)

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environmental awareness, eco-friendly alternatives such as chitin, Chitosan, etc., to the use of synthetic compounds are being considered. Keeping the above facts in view, the present study was focused on using Chitosan with conventional sand as filter media and evaluating its performance.

2. Materials and Methods

Water sample was collected from Kukkarahalli Lake, first main, Saraswathipuram, Mysore, Karnataka. Grab sampling technique was followed to collect the sample.

2.1.Experimental setup

Filtration was carried out in a Borosilicate glass column of height 1 m and diameter 0.10 m in which filter media was placed. The sample was conveyed through a pipe of diameter 5mm. A flow controller was used to control the flow of water at 100mL/min as shown in Fig 1.

Fig 1. (a) Representation of filter arrangements (b) Glass column

2.2.Column study

Chitosan flakes of depth 20mm was used, above the sand layer of depth 250mm, through which sample water was passed at flow rates of 100mL/min by maintaining a constant head of 100mm from the top surface of chitosan filter media.

2.3.Water quality parameters

The physical, chemical and bacteriological parameters were analyzed (pH, turbidity, total hardness, nitrates, fluorides, total solids and total dissolved solids and Total Coliform). The procedures followed to analyze the parameters of concern were according to the standard methods [Clesceri L. S. et al._{(1998)] listed in Table 1.}

Table 1 Standard Analysis Technique

Parameters Methods

Turbidity Nephelometric method

Nitrates Phenol di sulphonic acid method Hardness EDTA titrimetric method

Fluoride Alizarin visual method Total Coliform Membrane Filter Technique

Madhukar M et al. / International Journal of Engineering Science and Technology (IJEST)

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3. Results

The water sample was analyzed for its initial physico-chemical and bacteriological characteristics such as turbidity, pH, total solids, total dissolved solids, total hardness, permanent hardness, nitrates, fluorides and total Coliform. It was observed that the water was turbid and contained a high concentration of total solids. The obtained values are tabulated in the Table 2 and Table 3. The results indicated that the water was not potable as the values were exceeding drinking water quality standards given by Bureau of Indian Standards.

Table 2 Physico-Chemical characteristic

Parameter Concentration In (mg/L)

Total Solids 643

Total Dissolved Solids 356 Total Hardness (as CaCO₃) 182 Permanent Hardness (as CaCO₃) 173

Nitrates 25 Fluorides 1.60

Table 3 Physical and bacteriological characteristic

Turbidity (NTU) 83.4

pH 9.83 Total Coliforms/100mL 10000

The dual filter media was effective in reducing turbidity, nitrate and total Coliform Fig 2. The chitosan flakes used in the column study was having particle size ranging from 212µm to 425µm. The turbidity was reduced by 93%, Nitrate by 85 % and total Coliform by 100%. It was found that there was no significant reduction in total solids (45%), total dissolved solids (3%), total hardness (27%), permanent hardness (31%) and fluoride (25%). pH remained unchanged.

Fig 2. Removal Efficiency (%) of the composite filter

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4. Conclusions

•Since the particles size of chitosan was in the range 212µm to 425µm, the particles imparting turbidity was effectively trapped in the layers of chitosan and hence reduced by 93%.

•Chitosan and sand both have anti-microbial property and ability to inhibit the growth of micro organisms this is well depicted by reducing total Coliform by 100%.

•Chitosan was found to be effective in reducing inorganic non metallic constituent nitrate by 85%.

•It was observed that there was no significant reduction in total solids, dissolved solids, total hardness, permanent hardness and fluoride.

•This study reveals that combination of chitosan and sand as dual filter media is a promising method for treating the water.

References

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