Ezakheni water treatment plant had fallen into a state of disrepair resulting in a frequently interrupted supply of inconsistent quality water to its consumers in the Ezakheni and Ladysmith areas in KwaZulu-Natal. Water is extracted from the Tugela River, then clarified, purified and distributed to the bulk consumers, but intermittent maintenance and ageing technology had resulted in the overall plant efficiency falling to a dismal 20%.
“The plant, which operates at 48 Mega litres per day, serves an estimated population of 120 000. The purpose of the project was to refurbish the previously government owned water scheme under the guidance of the National Transfers Programme. “Uthukela District Municipality is committed to improving its Blue and Green Drop scores, as well as optimising its capacity to cope with the increase in demand;” says Pradeep Ramlall of consulting engineers AB Projects. “Fortunately, the upgrading of the plant has the full backing of the Mayor, Ms Dudu Mazibuko, who is committed to improving the areas water and sanitation services.”
Autotronix, a JV partner with Lindokuhle Engineering, was tasked to design, supply and install the new system based on the its extensive experience in the water treatment industry. The project started with a complete audit of the plant to establish where shortfalls existed in order to maximise the benefits of an automated system.
“Because of the isolated location of the water treatment plant, the available operators were all inadequately trained,” says Autotronix project manager, Collin Chetty. “The system requires specific and scheduled processes to take place in order for the supply and quality of the water to be adequate and this was just not happening.
“Fortunately, AB Projects had already convinced the management of the plant that a complete upgrade of the control system was necessary, so we were able to deploy our design team to site during November of 2012. The issues we faced were the remoteness of the location which affected logistics, as well as the lack of cellular communication in the area for the requisite wireless system. A great deal of forward planning was required to meet the scheduled deadline of end May 2013.”
Autotronix provided a state-of-the-art control system, which entailed the installation of a PLC and scada on an Ethernet backbone. One section of the field devices has been updated with an ASi valve interface and each of the 10 filters is now operated via its own customised control desk, which allows the operators to intervene and control the operation as and when required. “However, the system is designed to minimise intervention,” explains Chetty. “The automatic control architecture can capably ensure optimal plant efficiency and quality under almost all load conditions. We selected a Mitsubishi PLC due to its favourable cost-performance ratio and the scada system is from Adroit. The valves are from Bernard Actuators and incorporate an ifm ASi subsystem and all software, system design and related hardware were provided by Autotronix.”
By negotiating with a cellular provider to increase coverage in the area, the project had the additional benefit of improving telecommunications for all the region’s residents. “In addition, through a skills transfer programme, we have ensured that selected residents in the area are provided with job opportunities within the Department of Water Affairs. Furthermore, we utilised the local labour content during the various stages of project implementation and in this way provided additional job opportunities. In all of these ways, we have not only met the original goals of the project, but we have in fact exceeded them,” concludes Chetty.
For more information contact Collin Chetty, Autotronix, +27 (0)31 705 0403, collin@autotronix.co.za, www.autotronix.co.za
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