Question

The desirable limit of chloride content as per BIS standards in water for domestic supplies should not exceed 

1.

250 ppm

2. 350 ppm
3. 450 ppm
4. 550 ppm

Answer 1

Correct Answer - Option 1 :

250 ppm

Properties of groundwater	Reason	Drinking water standard
Temperature	As the atmospheric temperature does not reach the groundwater, it is effective till surface water.	10°C to 20°C
Colour	It is due to dissolved substances	5 to 20 CU (colour unit)
Turbidity	As groundwater moves at very low velocity, the turbidity produced is less.	5 to 10 TU (turbidty unit)
Alkalinity	As the atmospheric gases such as CO2 enters the ground through rain water and produces carbonates and bicarbonates responsible for alkalinity.	≤ 200 mg/litre
Chloride	The chloride ions come into solution in water in the underground aquifers, from the geological formation that stores water.	≤ 250 mg/litre
Fluorides	The fluoride ions come into solution in water in the underground aquifers, from the geological formation that stores water.	1 to 1.5 mg/litre