Supervisory control and data acquisition (SCADA) has an important role to play in the water sector, considering the increasing consumer base and limited capacity of urban local bodies (ULBs) to meet the growing demand. SCADA installation can help achieve efficiency in water usage through better management practices and enhanced customer information.
ULBs in India are beginning to deploy SCADA technology to improve service delivery. Central government-sponsored schemes such as the Jawaharlal Nehru National Urban Renewal Mission, the National Ganga Mission, Digital India and the Smart Cities Mission have provided the required impetus. Several cities such as Pimpri Chinchwad, Thiruvananthapuram, Bengaluru, Hyderabad and Delhi have taken a proactive approach in implementing a SCADA monitoring system. Smaller cities such as Vijayawada, Solapur and Nagpur too have implemented customised solutions to suit their needs.
Key features of SCADA systems
With a strong focus on data-based management, SCADA involves the setting up of a comprehensive online data and information base with tested software and equipment. The system provides data on the flow and volume of water at all locations. It also involves several dimensions of management information systems such as data acquisition, equipment installation to measure water supply parameters, networking, report generation and online monitoring.
Data acquisition
Accurate data acquisition forms a major part of the implementation process. Various parameters concerning the measurement of quantity, quality and control are logged after due validation, processing, time stamping and storing. The two parameters for quantity measurement are flow rate and level. The parameters recorded for quality measurement are free residual chlorine parts per million (ppm) at the water treatment plant and free residual chlorine ppm during the ELSR filling period and distribution. The control parameters logged are pump on/off status, frequency, amplifiers, revolutions per minute and valve position.
Instrumentation
Three measuring equipment solutions are installed to record the various parameters under study at the data acquisition stage.
Online information networking
Networking is critical to integrated management of the project. After data validation, it is processed for representation in reports and networked into a central place. The flow, level and chlorine accumulation at each plant and reservoir provide information on whether all the reservoirs have been supplied with enough water or not. The abnormal behaviour of a reservoir in terms of early/late filling, early/late distribution, low/high chlorine, overflows, etc. are brought to the notice of the water supply engineer. Secondly, the chlorine chart informs the user about the quantity of chlorine to be mixed with water during distribution.
Report generation
Reports on the daily operations and maintenance, historical trends of the reservoir, faults and chlorination, reservoir monthly summary report, and schedule derivation report can be generated and used for controlling and continuous monitoring of operations. These reports provide information on the reservoir capacity, unaccounted-for water (UFW), low chlorine, overflows, distribution schedule followed at the reservoir, failures that have occurred at the reservoir and comparison of actual versus planned maintenance of the quality of water, and quantity of chlorination during distribution.
Key benefits and the way forward
The primary benefits of the SCADA system include the elimination of overflow and inflow and outflow leakages at reservoirs, considerable reduction in UFW, scheduled cleanup of reservoirs and continuous monitoring of free chlorine levels. The availability of online information assists the supervisory staff to implement timely corrective measures. Further, benefits such as effective control and better water quality are of immense value to customers.
The potential for the installation of SCADA systems in India is huge given the growing demand for urban infrastructure services. Going forward, there is a need to create customised SCADA solutions tailored to the needs of users, along with features like data integrity, city-wide integration and real-time monitoring.
