Atleast 70% of Jaipur receives water with a high concentration of TDS or contaminated by bacteria or both: A report on the quality of piped water supply in Jaipur city based on data from NEERI and PHED Rajasthan

Jaipur, the capital of Rajasthan, receives a little over 276 million litres of water every day. This is predominantly groundwater, with water from the Ramgarh lake forming a small percent. Using data obtained from the Public Health Engineering Department of Rajasthan and from NEERI, this article traces the route of water from its source to the consumer. The treatment measures taken and the quality of water at various points of treatment are explained. The article ends with a list of suggestions for improvement.

Background

Jaipur, the capital of Rajasthan is one of India's modern cities with 3.1 million (Census 2011) residents.  Jaipur is largely dependent on groundwater for its drinking water supply: 90% of the total drinking water demand of the city is dependent on groundwater, while 10%  is supplied from the Ramgarh Lake situated 35 km from the city. The water supply in the city is maintained by Public Health Engineering Department (PHED) Rajasthan.

The depth of the ground water table varies from 15 to 40 m with seasonal variations of 1 to 3m. There are 990 tube wells over the city through which 276 million litres per day (mld) of raw water is fetched.

Ramgarh Lake is the only surface water source of the city. It is an impounded reservoir located 35 km northeast of the city. The lake is dependent on rainfall for its water supply.  It was constructed in 1903 with a gross storage capacity of 2650 million cubic feet. Due to the semi-arid climate zone, rainfall is sparse. Thus the lake almost dried up. Presently about 0.13 mld (0.35 lakh gallon/day) of water is taken from the lake due to erratic rainfall.

The water supply system in Jaipur

There are two water treatment plants in the city

1. Laxman Doongri Treatment Plant - Located in the eastern fringe of Jaipur city on the Jaipur Delhi Bypass, it is city's prime water treatment plant. In the year 1956, the capacity of the plant was augmented to treat 33 MLD of water. Further reorganization of the Jaipur water supply was undertaken in the year 1963 and the total design capacity of the filter plant was increased to treat 60 MLD of water. Presently however, due to the acute shortage of water in Ramgarh Lake the plant is run to treat only 0.13 MLD of water.
2. New Filter Plant – It is located near the Band Gate Intermediate Pumping station. However due to paucity of water the plant has been closed down for three years. The plant has been shown by dotted lines in figure-1.

Figure-1: A simplified pictorial representation of the drinking water supply system of Jaipur city.

All the basic water treatment procedures like pre-chlorination, alum, lime dosing, flocculation, settling, filtration and chlorination are carried out in the Laxman Doongri treatment plant. Water from the treatment plant is then stored in clean water reservoirs.

There are three Clean Water Reservoirs (CWRS) where the treated water is stored after disinfection. The three reservoirs have the following storage volumes 1.89, 3.7 and 1.5 ml. The reservoirs are constructed of stone masonry and RCC. According to PHED officials the CWRs are well ventilated but there is no provision for control of mosquito and other aquatic insects. The reservoirs were last cleaned in December 2000.

The water from the reservoirs is then pumped into CWRS of the various zones of the city. Then from the associated CWRs to the Overhead Service Reservoir of associated locality, gravity takes care of the water supply. There are a total of 54 CWRs and 57 service reservoirs (one CWR may supply water to two SRs).The city is divided into two divisions- north and south division. Each Division is then divided into five subdivisions and each subdivision is again further divided into two or three Chowkis forming a total of 27 chowkis.

Fig 2- Administrative divisions for water supply in Jaipur

Water quality checks:

The National Environmental Engineering Research Institute, Nagpur in 2001 had carried out quality checks of the water at all the stages i.e treatment level, clean water reservoir level, service reservoir level and at consumer end level for the three seasons (monsoon, summer and winter).

• Water samples were monitored for all the physico-chemical at treatment level and clean water reservoir level..
• At the service reservoir and consumer end, water samples were tested for residual chlorine and bacteriological parameters.

Water quality analysis:

Below is an analysis of the test report from the treatment level up to the consumer end level.

1) Treatment level

All the physio-chemical parameters as indicated by BIS :10500 norms were tested, but no bacteriological test  was done. Out of the physio-chemical parameters the samples had TDS, Alkalinity, Hardness, Calcium and Magnesium, at a much higher concentration than the permissible levels. Samples were collected for six days in each season, but in the following graphs the average values of the parameters have been shown. In all the graphs the red line indicates the permissible concentration of the parameters.

2) Clean water reservoir level