Quality assessment of the noncarbonated-bottled drinking water: comparison of their treatment techniques

Abstract

This study presents a comparison among different-bottled drinking water commercially available in Lahore Pakistan. For that, five locally produced drinking water brands and four national brands were selected. Different physical, chemical and microbiological parameters like EC, pH, salinity, TDS, Na+, K+, Ca2+, Mg2+, Cl−, F−, Fe3+, SO42-, NO3-, PO43-, Arsenic (As), total coliforms and faecal coliforms/Escherichia coli were analysed . Results showed that there was a remarkable difference in the quality. Analysed data exposed that EC range was 141–298.3 μS/cm, pH 7.35–7.95, Salinity 0.1 ± 0.02 ppt, turbidity 2.13–2.45 NTU, TDS 85–182 mg/L, sodium 12–71.2 mg/L, potassium 0.1–2.4 mg/L, calcium 16–40 mg/L, mag- 30 magnesium 2.5–35 mg/L, chloride 35–95 mg/L, fluoride 0.29–0.94 mg/L,Iron below detectable limits to 0.17 mg/L, sulphate s 22–120 mg/L, phosphates 0.023–0.17 mg/L, nitrates 0.9–3.6 mg/L and arsenic were 0.0005–0.01 mg/L in these brands of drinking water. The analysed data was compared with the PSQCA, US–EPA and WHO standards. In only one brand of water, the concentration of sodium (71.2 mg/L) and arsenic (0.01 mg/L) was higher than permissible limits. For microbiological contamination brand E (80 colonies/100 mL sample), C (25 colonies/100 mL sample), S (100 colonies/100 mL sample) and K (15 colonies/100 mL sample) were .Some of these water brands examined were deficient in essential minerals like S brand in which Magnesium was only 2.5 mg/L and K and G brands in which calcium was 16 mg/L and 20 mg/L, respectively It was observed that treatment plants having raw water of low TDS 60 or those whose process based on 50% mineral dosing and 50% blending were cost-effective. Data presented in this study are important because it can be considered as baseline data for future.