Determination of Total Dissolved Solids (TDS) of RO Purified Drinking Water Samples in Raipur

Sudheer Bhoi^1,*, Chunendra Kashyap¹, Sagar Kumar Rajak¹, Shobhana Ramteke¹

¹ School of Studies in Environmental Science, Pt. Ravishankar Shukla University Raipur (Chhattisgarh) 492010. India.

Abstract

This research work deals with the TDS and physiochemical parameters of RO purified drinking water  in Raipur region. Current pollution trends taught us that it is necessary to drink RO purified water but we must have to know the quality of RO purified drinking water because many peoples used RO water for consumption.  This paper deals about RO water with special reference to TDS, but another physical parameter viz. pH, EC, Salt, Temperature and chemical parameter viz. Hardness (total hardness, calcium hardness & magnesium hardness) and Total alkalinity and NA⁺, K⁺ of RO purified water also tested and studied. We are able to know about the correlation between TDS and many physiochemical parameter after study about this research paper. 20 water samples collected from different places of Raipur city. The purpose of the research paper  is to ensure the quality of RO purified water that people using for drinking purpose. Many samples of RO purified waters TDS level is below the permissible limit of BIS guidelines in the part of result and discussion the samples are mentioned properly in this present paper. Peoples should aware about the consequences which can occur after long term consumption of RO purified drinking water.

Keywords: RO purified drinking water, physiochemical parameters, TDS,  BIS, WHO.

 Introduction

Raipur district is not only the capital of Chhattisgarh but also heart of Chhattisgarh state. Very huge number of peoples are living in Raipur city. Raipur city is highly polluted because of large number of industries and large population. Due to high pollution of water, peoples are allowed to use RO purified water for safe drinking. But it is necessary to know that RO water is healthy for us or not. Hence it is important to know about physical and chemical parameter of RO purified drinking water. The physical parameters like EC, TDS, pH, Salt and temperature are mostly notable.  The TDS of water is commonly becomes low after purification using RO. This phenomena leads to remove essential minerals from drinking water which can cause severe health consequences after long term consumption of  RO purified water.

TDS correlates positively with EC and affects pH, the higher the TDS the higher the conductivity and lower the pH, towards the acidity. Similarly TDS strongly correlated with TH and Ca²⁺  etc. According to BIS & WHO the upper limit of TDS levels in water is 500 & 300 ppm respectively. But both high and low TDS levels is harmful for human beings. A certain levels of TDS is required for consumption. Hence the aim of this research work is to understand the quality of water with special reference to TDS because it is essential to aware people about the quality of water they are consuming.

Materials and methods

Sampling Area and Collection

RO water samples were collected from January 2020-february 2020 from different 20 location of Raipur city for analysis of physio chemical parameters. Sampling points for the samples were designated as Gudhiyari (R1), Sailendra Nagar (R2), Pt. R. S. U. (R3), Kota (R4), Amlidih 1 (R5), Tatibandh (R6), Aaims (R7), Pandri (R8), Purani Basti (R9), Mahima Vihar (R10), Siltara (R11), Changora Bhatha (R12), Kabir Nagar (R13), Amlidih 2 (R14), Railway Station Road (R15), Dr. Ambedkar Hospital (R16), Mova (R17), Santoshi Nagar (R18), Rohinipuram (R19), Vip Chowk (R20). (Figure 1)The samples were collected differently for multiple tests. pH, temperature, TDS, and conductivity RO water are measured by using pH 7200 (Digital pen tester). The samples were labeled cautiously and transported to the laboratory and stored in the refrigerator at about 4°C prior to analysis After collection, they were stored at room temperature. The chemical parameters Total hardness, Ca²⁺, Mg²⁺, Total Alkalinity, Na⁺, K⁺ etc. were determined by using titration method (TH, Ca²⁺, Mg²⁺, Total Alkalinity) and digital flame photometer (Na⁺, K⁺) respectively.

Figure 1: Representation of the sampling location.

Result and Discussion

PHYSICAL CHARACTERISTICS OF RO WATER

The physical characteristics of RO water samples are summarized in table 1 in which Temperature varies from 24.1-25.5 (mean value is 24.72 ⁰c.) temperature of RO water is not above permissible value according to BIS. The pH varied from 6.65-7.7 (mean value  7.37) where 4 samples are below  the 7, can considered as slightly acidic. Acidity is under the permissible value of both BIS. EC varied from 9-1072 µS/cm (mean value 331.86 µS/cm). EC was fairly correlated with TDS. The TDS value is recorded very low in 4 water samples. In the all 20 samples TDS ranging between 6-716.66 mg/l (mean value 159.49 mg/l. TDS correlated with pH , EC , Salt , Total Hardness, Ca²⁺, Mg²⁺, Total Alkalinity, Na⁺ , K⁺ and all other physiochemical parameters. Also TDS is the main concern of this article. The salt content varied from 4-525mg/l with mean value of 159.49 mg/l. correlation matrix of physio chemical parameters are shown in table no. (5).

Table 1. Physical parameters of RO purified drinking water of Raipur District.

Table 2.  Standard deviation and Confidence limit of physical parameters of RO water samples

This table shows the standard deviation of different parameters of RO water samples and the confidence limit of parameters of RO water samples.

CHEMICAL CHARACTERISTICS OF RO WATER

The chemical characteristics of RO water samples are summarized in table (3). The total hardness (TH) was ranged from 20-238.75 mg/l with mean value of 25 mg/l in the term of CaCO3. The total alkalinity (TA) was ranged from 3.646-25.522 mg/l with mean value of 10.5734 mg/l. The Ca²⁺ value was ranged from 15-146.25 with mean value of 56.5 mg/l. The mg²⁺  value was ranged from 0-56.25 mg/l with mean value of  29.56 mg/l. The Na⁺ concentration ranged from  3-93 mg/l with mean value of 35.35 mg/l.  Sodium is fairly correlated with TDS and potassium. K⁺ is ranged from 2-40 mg/l with mean value of 17.35 mg/l. correlation matrix of physio chemical parameters are shown in table no. (5).

Table 3. Results of chemical parameters of RO water samples.

Table 4. Standard deviation and confidence limit of chemical parameters

Figure 2. Spatial distribution of Cation in RO water samples.

Figure 3. Relative abundance of ions in RO water samples.

 Conclusion

15 out of 20 RO water samples are below the permissible limit with reference to TDS according to BIS. 3 samples are under the permissible limit of Indian standard. While 6 samples are below 50 mg/l of TDS those samples are very harmful for consumption. In this research work it is concluded that the RO purified water is found the lack of essential dissolved solids and this may cause harmful effect to human health. Due to high level of pollution it is necessary to drink pure and  safe water and  the quality of water also matters in our health. RO companies should change the technique used in water purification in their RO water purifier and they should  manage the TDS level of RO water and make the RO purified water under Indian standard of permissible limit (BIS). Also government should aware people about the health issue they may have face after consumption of low TDS water.

 Acknowledge

I must acknowledge my supervisor, Mr. Sagar Kumar Rajak, Guest Lecturer, School of Studies in Environmental Science, Pt. Ravishankar Shukla University Raipur, I must first express my sincere gratitude to him. With his supervision, my effort is shown in current research paper. I am grateful to Dr. Shobhana Ramteke, Guest Lecturer-cum Teacher in charge, School of Studies in Environmental Science, Pt. Ravishankar Shukla University Raipur, who has been helping and facilitating during my dissertation work.