Automated Control

SCADA system helps PCMC in real-time monitoring of water and wastewater quality

The Pimpri Chinchwad Municipal Corporation (PCMC) in Maharashtra has been consistently undertaking technological initiatives to improve the delivery of municipal services in the city. One such initiative entailed the installation of a centralised supervisory control and data acquisition (SCADA) system for developing an accurate database for measuring the water supplied and sewage generated. The objective is to optimise the unit cost of water and sewage treatment, eliminate overflows, and improve transparency, efficiency and customer satisfaction.

Prior to the installation of the SCADA system, the fundamental problem faced by PCMC was the lack of accurately measured data on various parameters such as flow, leakages and chlorine levels. Through the acquisition of crucial data online, the SCADA system ensures real-time monitoring and control of the water distribution and sewerage networks.

Over the years, PCMC has developed and integrated its entire water supply and sewerage network with the SCADA system. The system automates most of the control process at the water treatment plants (WTPs) and sewage treatment plants (STPs). This has reduced the operating costs and number of man-hours required for maintenance, and increased the efficiency of the water supply and sewerage networks.

SCADA project

PCMC initially installed a SCADA system in its water supply network in January 2010. Under the system, flow meters were installed at the raw water pumping station at Ravet, and the WTPs at Nigdi, on the two main pipelines supplying water to the elevated storage reservoirs (ESRs) and at all the ESRs. The SCADA system helped the civic agency in monitoring water consumption at each stage. It enabled it to conduct real-time monitoring of the water flow, purification levels, storage at the ESRs, and the quantity and duration of the treated water supplied.

Later, the civic agency installed the SCADA system at six newly built STPs at Chinchwad Phase II (30 million litres per day [mld] of water), Ravet (20 mld), Akurdi (30 mld), Dapodi (20 mld) and Charholi (21 mld). However, the old STPs – Chinchwad Phase I (30 mld), Sangavi (15 mld), Chikhali Phase I (16 mld), Chikhali Phase II (16 mld), Kasarwadi Phase I (40 mld), Kasarwadi Phase II (40 mld), Kasarwadi Phase III (40 mld) and Pimple Nilakh (20 mld), did not have a SCADA system. Thus, in July 2012, the standing committee of PCMC decided to install a centralised SCADA system covering the entire sewerage network, including old and new STPs and sewage pumping stations (SPSs).

The centralised SCADA system is now fully operational. It monitors the entire sewerage network comprising 13 STPs and 33 SPSs. A master control room has been set up with engineering and operator stations. Besides, a viewing station has been established at PCMC’s head office for continuous monitoring and control. And an online information system has been installed for generating daily and monthly reports for supervisory control. The installation of the centralised SCADA system involved a total cost of Rs 42 million.

Data and information system

With the objective of improving data management, a comprehensive online data and information system has been set up with tested software and equipment. The system comprises several dimensions of management information system (MIS) such as data acquisition, report generation and online monitoring.

Data acquisition

A major function of the MIS is accurate data acquisition. Data pertaining to various quantity and quality parameters is uploaded after validation, processing and storing. For quantitative analysis, real-time measurement of the flow rate, pressure and sump level is undertaken. For qualitative analysis, the levels of chlorine, conductivity, dissolved oxygen and pH are measured.

Instrumentation

Various types of measuring equipment have been installed to record different parameters. These include flow meters, ultrasonic level sensors, pressure transmitters and analysing instruments for monitoring water quality parameters.

Flow meters are typically used to measure the outlet flow rate at the STPs and pumping stations. They also measure the flow rate at junction points. Further, water quality analysers are used to measure the level of chlorine, pH, dissolved oxygen and conductivity at the inlet and outlet points.

Online information storage and report generation

Once the data is collected, it is networked into a central place and then processed for representation in reports. The flow rate, pressure, chlorine, pH, dissolved oxygen and conductivity at each plant are recorded on a real-time basis. This process results in two major benefits. First, any abnormal behaviour in terms of overflows, high/low pressure, high/low chlorine, high/low pH and high/low dissolved oxygen is brought to the notice of the concerned engineer. Second, the information on the current chlorine, pH and dissolved oxygen levels helps the civic agency in maintaining the quality standards.

The system generates several reports – daily reports, historical trends of the STPs and SPSs, monthly summary reports, date-wise alert/alarm summaries, and quantity and quality overview reports for control and continuous monitoring of operations. Besides qualitative and quantitative analyses, these reports also provide information on the list of failures that have occurred at the plant due to low voltage, panel faults or sudden shutdowns. The comparison of actual versus benchmark sewage quantity is also possible using this system.

Key issues and challenges

Various issues and challenges emerged during the course of implementation of the SCADA system. Software and equipment customisation involved a lengthy process since the engineers and other officials were not familiar with the SCADA system. This forced the civic agency to outsource the operations and maintenance of the system to a third-party vendor. Further, due to a lack of proper internet connectivity in some areas, real-time information delivery becomes difficult. Besides, frequent power cuts also affect the performance of the system.

Key benefits and the way forward

The SCADA system has helped the civic agency to centrally monitor sewage levels, the amount of treated sewage, and quality parameters including the dissolved oxygen level, chemical oxygen demand, etc. It has resulted in several benefits including facilitating collection, storage and monitoring of sewage data on a real-time basis. It immediately reports/notifies the concerned official about any problem and the area of occurrence. The system also enhances accountability and transparency in the delivery of services by the civic agency. Other benefits of the SCADA system include the elimination of overflows, inflows and outflow leakages at reservoirs and pumping stations, scheduled clean-ups of reservoirs, and continuous monitoring of chlorine levels.

Going forward, PCMC plans to integrate the SCADA system with mobile-based applications and enhance the level of automation for greater transparency and accountability. The SCADA project will serve as an appropriate example for other municipal agencies to learn from and implement similar projects in their cities.

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