Plant Rehabilitation

DJB implements integrated water management system

The Delhi Jal Board (DJB) was constituted under the Delhi Water Board Act, 1998, to provide water supply, sewage disposal and storm water drainage facilities in the National Capital Region. The utility is responsible for the treatment of groundwater and raw water from various sources such as the Yamuna river, Bhakhra storage and the upper Ganga canal, and the production and distribution of potable water. The DJB is responsible for water distribution across the city, except in areas under the New Delhi Municipal Council (NDMC) and the Cantonment Board. Besides, DJB oversees the collection, treatment and disposal of wastewater in all parts of the city, including the NDMC and cantonment areas. In February 2015, the board also started supplying potable water in the Dwarka area, which was earlier served by the Delhi Development Authority.

Delhi is one of India’s fastest growing metropolises with a population of around 26.5 million as of 2016, recording an annual growth rate of over 4 per cent during the past decade. The city’s increasing population has put tremendous pressure on its existing infrastructure.

The city’s current water demand is estimated at 1,100 million gallons per day (mgd). Against this, DJB supplies around 890 mgd of potable water. Some of the key reasons for the demand-supply gap are the low water supply from treatment plants and the under-utilisation of underground water reservoirs. According to a DJB report published in 2015, at least 40 per cent of water is wasted in leakages, further widening the demand-supply gap. In addition, the sector is facing infrastructural issues, which have contributed to the water scarcity in the city. In order to reduce the demand-supply gap and boost water supply in the city, DJB deployed 320 new tankers in 2017.

Apart from the production and distribution of potable water, DJB owns and operates several water treatment plants (WTPs), and associated pumping and booster pumping substations. It operates a total of eight zonal water testing laboratories and nine WTPs across the city. In order to monitor the quality of water supplied, samples collected from residential areas are tested in zonal laboratories on a regular basis. About 500 water samples are tested in the laboratories every day. Drinking water generated at the WTPs is also tested before release. However, the laboratories lack advanced equipment for monitoring various parameters that affect the quality of water. Moreover, the data available from various laboratories is not properly maintained. As a result, it becomes difficult to assess the overall quality of water.

In order to reduce the demand-supply gap, address infrastructural issues and cater to the growing consumer base, DJB has been taking a number of initiatives over the years. These include the deployment of advanced online solutions for revenue management, grievance redressal, leakage detection, online bill payment and tanker distribution management. One of the key projects undertaken by DJB is the rehabilitation and automation of the WTP at Bhagirathi.

Background and progress

The Bhagirathi WTP was designed and commissioned in 1983, with a capacity of 105 mgd. However, the plant’s inflexible, manually operated functions did not allow DJB to promptly respond to variations in water demand. Further, the plant witnessed a substantial water loss of more than 10 mgd due to sludge drainage and filter backwash. The challenges pertaining to the availability of water, water quality, equipment efficiency, leakages and energy usage called for an integrated management system at the Bhagirathi plant. Thus, DJB decided to improve operations at the Bhagirathi WTP by minimising operations and maintenance (O&M) costs, reducing non-revenue water, and monitoring water and energy utilisation.

To this end, the board conducted various surveys through appointed consultants. As per the survey results, it was possible to reduce the production cost of potable water, minimise electricity charges, and effectively utilise the existing manpower through plant rehabilitation and automation, and outsourcing of operations.

The DJB awarded the contract for rehabilitation and automation of the Bhagirathi WTP to Larsen & Toubro (L&T) in 2017 with a one-year defect liability period. The company will also undertake O&M of the plant for 10 years. L&T assigned the contract for providing turnkey electrical, control and instrumentation solutions for the Bhagirathi WTP and its distribution areas to its control and automation (C&A) business unit.

The C&A unit’s scope of work included design, engineering, development, testing and commissioning of a state-of-the-art supervisory control and data acquisition (SCADA) system, control systems along with instruments for plant automation, a central control room at Bhagirathi, a pumping station at Muradnagar, a raw water pump house at Sangam, a distribution control room, 21 underground reservoirs across Delhi and five control stations for operators.

The iVisionmax SCADA system was installed with programmable logic controllers (PLCs) and remote terminal units to achieve the desired level of automation. It allows operators to view the status of pumps and water levels. The software can generate alarms and allow users to access their system information over the internet using web client. The system comprises a redundant server configured in the main/standby set-up, with the standby server operating from the disaster recovery site.

iVisionmax allows operators to view the status of pumps and water levels. The key benefits of the system are:

  • Increased productivity
  • Reduction in operation costs
  • Reduction in down time and maintenance costs,
  • Availability of accurate data/information on a real-time basis, enabling timely decision-making
  • Improved and consistent product quality
  • Effective use of manpower in other activities
  • Greater environmental compliance and values
  • Reduction in the reaction time to problems thereby preventing critical situations
  • Precise and real-time guidance to the field service team
  • Greater customer satisfaction

The SCADA solution monitors and controls the Bhagirathi WTP, a substation, a chemical house, two filter houses with 40 filter console desks, a sludge pump house, a dirty backwash pump house, and 6 mgd recycling plants, among others. Apart from this, the distributed architecture helps in remote monitoring and management of 21 underground reservoir units and 20 wells using GPRS data transmission. These systems communicate with a variety of sensors to monitor parameters such as flow and pressure from water sources into tanks, flow and pressure from tanks into the towns, and the tank level. It also controls the pumps and valves at each station to allow or disallow the water to flow into the other.

As part of this initiative, C&A also commissioned seven hot redundant PLC systems with SCADA, 21 remote terminal units to monitor various convert rooms, 48 stand-alone PLC panels and consoles, a wireless network and a central command centre. All these systems are connected with each other on multiple communication channels including GPRS, Wi-Fi, leased line and local area network.

The way forward

Accurate real-time alerts and online reports along with user-friendly dashboards have helped DJB closely monitor plants operations, identify losses, automate operations, and improve efficiency and network command. The board is now able to monitor the  performance of equipment on a real-time basis. The system provides visibility and early awareness of potential issues.

This helps in the collection, storage and monitoring of data on a timely basis. Further, it enhances accountability and transparency in the delivery of services by DJB.

Going forward, the successful implementation of the integrated water management system will serve as an example for other water utilities.

 

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