Ensuring 24×7 Supply: DJB’s strategies for water management

The growing population in Delhi is leading to an unprecedented demand for water from residential and industrial areas. The responsibility for the production and distribution of potable water in Delhi lies with the Delhi Jal Board (DJB), providing around 990 million gallons per day (mgd) to the city’s population of approximately 21 million. In addition to its critical functions, it undertakes the collection and treatment of wastewater for non-potable purposes and the disposal of sewage. The DJB also offers facilities for testing water samples and provides technical support for the installation of rainwater harvesting systems, as well as wastewater treatment for non-potable purposes. Currently, the DJB is developing an augmentation plan to improve water supply in Delhi, along with other key initiatives such as setting up new water treatment plants (WTPs), ensuring 24×7 water supply, and deploying new technologies such as electromagnetic flowmeters and supervisory control and data acquisition (SCADA) systems.

Overview of water supply in Delhi

Delhi predominantly relies on surface and ground water sources to meet its water dema­nd, which exceeds 1,200 mgd. The primary sources of surface water lie in the neighbouring states of Uttar Pradesh and Haryana, contributing approximately 254 mgd of water from the Ganga river and about 612.5 mgd from the Yamuna river. Amongst other sour­ces, the DJB relies on groundwater extraction, WTPs and water restored from rainwater harvesting to meet the city’s water requirements. Currently, it has a water pipeline network spanning over 15,300 km, along with 123 primary un­der­ground reservoirs (UGR) and booster pumping stations. This network is further complemented by 16 Ranney wells and 4,800 tube we­lls. The DJB operates 10 functional WTPs, nine of which are major plants, while one has a low capacity of 1 mgd at the Khelgaon complex. Notably, 90 mgd of water recycled from th­ese WTPs is utilised for non-potable purposes such as irrigation, horticulture, washing and power plants. Additionally, the DJB is actively add­ressing water deficits in areas by deploying 1,240 tankers on the ground. It aims to supply quality water directly through taps, with an im­pressive 99 per cent of its water samples passing quality tests.

At present, the DJB has a water supply coverage of 93 per cent and successfully maintains water availability of more than 135 litres per capita per day. The board aims to achieve a coverage of 100 per cent and, therefore, plans to execute some short-term and long-term strategies. As part of the short-term strategy, it has initiated the installation of effluent treatment plants (ETPs) for additional water supply. Currently, there is 570 mgd of treated effluent available, out of which 90 mgd is being utilised. It is also in the process of constructing a 105 mgd-capacity WTP at Chandrawal and another 50 mgd-capacity WTP at Dwarka. The construction of a water recycling plant in Bawana, with a capacity of 2 mgd, is also under way and is ex­pected to be completed by May 2024. As part of its long-term strategy, it has proposed the construction of three dams, namely, Renuka in Himachal Pradesh, and Kishau and Lakhwar Vyasi in Uttarakhand, in consultation with the respective state governments. These dams are expected to make 180 mgd of water available to Delhi by 2028.

Key initiatives by the DJB

24×7 water supply

The execution of a 24×7 water supply initiative is contingent on reducing the extent of non-revenue water (NRW). The DJB has undertaken the task of reducing the current level of NRW from 47 per cent to 5 per cent in the city by implementing district-metered areas (DMAs) in its 24×7 water supply projects. Some of the ongoing 24×7 water supply projects are nearing completion in various areas, with Malviya Nagar being 98 per cent completed, Nangloi being 78 per cent completed and Mehrauli-Vasant being 80 per cent completed. Apart from these initiatives, the DJB has undertaken a large project for the refurbishment of the Chandrawal WTP and all related works in its command areas. There are plans to cover the entire city with DMAs, for which detailed project reports have been submitted by consultants and tenders have been invited for the trans-Yamuna areas.

Regeneration of waterbodies and installation of RO water purification plants

Recently, the DJB has undertaken the rejuvenation of existing waterbodies and the creation of new waterbodies. Under the Atal Mis­sion for Rejuvenation and Urban Transfor­ma­tion 2.0 programme, it is currently working on 60 waterbodies belonging to various entities such as the Delhi Development Authority and the Revenue Department of the Delhi government, among others. Of these, 35 have been completed. In the next two to three years, the DJB has plans to utilise over 215 mgd of treated water by ETPs for recharging waterbodies, watering parks, forests, etc. Additionally, the DJB is planning to set up 500 water purification plants based on reverse osmosis (RO) in various areas of the city. These plants will include large RO installations near tube wells and lakes, as well as sm­a­ller community plants in areas where tanker services cannot be easily provided.

Deployment of technologies

The DJB is making efforts to enhance the performance of the existing water network system in Delhi. It is particularly focused on improving the monitoring of its WTPs by integrating new technology. To this end, it has begun the installation of electromagnetic flowmeters at WTPs, underground reservoirs and water pipelines, the setting up of SCADA centres and integrating SCADA systems at WTPs. So far, it has installed approximately 3,000 electromagnetic flowmeters, which will be helpful in mapping pre­ssure and flow variations over 24 hours. Additionally, the DJB has set up a SCADA centre at its head office in Jhandewalan to monitor the supply of water across Delhi in real time. The data collected through this is used for eff­ec­tive water leakage management. More­over, at present, some of its WTPs, including those in Sonia Vihar, Okhla and Dwarka, are equipped with SCADA systems. They monitor and record all the key parameters of water quality such as turbidity, salinity and chlorine levels. This data can be accessed remotely and the system can issue priority alarms in case of an emergency.

Issues and challenges

The execution of these initiatives presents several challenges for the board. The involvement of multiple agencies in these projects, such as public works departments and municipal corporations, makes their delivery complicated. The replacement of old pipelines and construction of new WTPs and ETPs require complex coordination with road works and land acquisition, necessitating engagement with their res­pective authorities. This causes delays in project implementation. Further, the laying of pipes in residential areas is often hindered by the lack of space. The road sections opened for th­is purpose must be promptly restored to avoid public inconvenience.

Further, the installation of flowme­ters has its own set of challenges. It has to ga­ther data from the old underground pipeline net­work, which is difficult to identify, locate and assess for different parameters su­ch as material, size and depth of pipelines. Similarly, the deployment of SCADA is hindered by the lack of signals and an internet network in many containment areas in the city. Moreover, the extent of metering is currently at a low level of 65 per cent, falling short of the targeted benchmark of 100 per cent.

The way forward

The DJB plans to build a robust water network for Delhi, and this requires collaboration and support from other departments and citizens, as well as learning from other countries such as Israel. It has set an ambitious target to further lower the extent of NRW in the city to 5 per cent. To achieve this, the DJB plans to replace 35 per cent of non-functional connections in the next two to three years and also urges consumers to conserve and save water. It is paving the way for creating awareness am­ong the ma­sses through campaigns on press media and social media pl­at­forms. Additio­na­lly, the board is making effor­ts to educate students on the concept of water supply and its treatment by visiting schools and inviting students to their WTPs. Moreover, the DJB aims to prioritise wa­ter demand management by promoting the use of water-saving fixtures and dual-system-type flushing, and discourage ex­cessive showering in households to save significant amounts of water.

Based on a presentation by Er. Dalbir Singh, Additional Chief Engineer, DJB, at a recent India Infrastructure conference