What comes out of your tap in Gauteng is some of the healthiest and highest quality water in the world – very often, a far better proposition than bottled or spring water that does not have to conform to Rand Water’s strict health and quality requirements.
Rand Water's 'shop floor' covers more than 18 000 km2 operating on a 24/7 basis and with the health of over 10 million people as its responsibility. No factory in the world can boast of such a scale of operations and responsibilities. In fact, Rand Water is one of the largest water purification schemes in the world analysing, treating and delivering immense quantities of water every second for industrial and domestic use.
"As with most large enterprises," says Sam Shorer, automation and IT consultant to Rand Water, "the need to address an immediate problem gets assigned a higher priority than the long-term implications of the problem. This is a natural and healthy evolution but often results in stop-gap measures that work in isolation from one another. There comes a time when a complete strategic rethink is necessary, and that is what the Engineering Division in Rand Water is currently busy with."
Rand Water's distributed instrumentation at purification plants, reservoirs and pumping stations are acquiring realtime data from a multitude of sensors and transmitters that measure water flow and pressure as well as data from hundreds of analytical instruments monitoring such parameters as pH, conductivity, chlorine-residual, turbidity and water composition. Previously, measurements were logged manually and locally by operators or supervisors. This information then gradually made its way to Rand Water's head office in Rietvlei where it was collated and analysed. Only after this could discrepancies be found which usually indicated equipment malfunctions, inefficiencies, water loss, etc that led to a remedial action.
Over the last five to eight years, Rand Water has installed a large network of PLCs to provide the first layer of consistent data collection and control in its modernisation and upgrading process which also involves the conversion of cable links from copper to fibre-optic. Currently, about 70-80% of instrumentation is connected to these PLCs. The next step was to establish an HMI solution that aimed to overcome the shortcomings of Rand Water's legacy system and that would manage the large and geographically distributed PLC network while providing management and engineers with the required integrated control and decision support facilities. In order to enhance the existing PLC/scada infrastructure that primarily handled pump controls, Rand Water has recently chosen Wonderware's InTouch, as a principal scada system for its chemical productions and dosing process monitoring and control.
"The new system will improve our capability for process monitoring as well as data gathering. The end aim is to provide a centralised, accurate and realtime picture of Rand Water's huge water purification processes and delivery network infrastructure," says Shorer. "This, in turn, will allow us to promptly deal with potential problem and identify improvement areas, which inevitably will lead to gradually optimise the network for better overall operation efficiency - something that can only occur if we have the correct and timely information from all the data sources. Management has been impressed with the initial results that we obtained with InTouch as part of the advanced pH control systems installed at our massive carbonation plants in Vereeniging and Zuikerbosch. The carbonation pools are amongst the largest in the world and form an integral part of the complete water purification process. This success has led to the decision that other Rand Water's chemical production and chemical dosing facilities will be monitored and controlled by Wonderware solutions - with InTouch as HMI and InSQL as data collection and logging. For the first time ever, managers and engineers in Rand Water are getting realtime, meaningful information on their PCs, using standard MS-Office software, that is giving them an unprecedented level of monitoring and decision support."
Working up the information pyramid, one of the future projects for Rand Water will be to aggregate the information from the distributed InSQL systems and to make this information available to head office management for the monitoring the whole operation of bulk water supply throughout Gauteng at a glance. Another critical factor will be the optimisation of energy and power utilisation.
Rand Water, with its track record of delivering some of the healthiest water in the world, is looking forward to being involved with countrywide and also worldwide water management initiatives. "Rand Water is a large organisation with great goals and important targets," comments Shorer. "The current modernisation initiatives are constantly being reviewed and modified in order to sustain our ability to deliver the highest quality of water to every person in the Gauteng area and beyond."
Mike le Plastrier, Futuristix
011 723 9900
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