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Elandsjagt Supply and Install New Filters

Water Treatment Works 105 000 000L/day


Project Value: R 27,714,443.00

Client: Nelson Mandela Bay Municipality

Completion Date: 2016

Consulting Engineer: Aurecon


The Elandsjagt Water Treatment Works, falling under the Nelson Mandela Bay Metropolitan Municipality, supplies potable water to Port Elizabeth and surrounding areas. At the time, the existing filter system, spanning some 12 m in length by 7 m wide, comprised of 12 rapid gravity filters with a pipe lateral under drainage system. It was noted that the efficiency of the filters was decreasing due to structural failure of the filters. Eigenbau was awarded the contract to design, supply, deliver, install, test, amd commission the necessary civil, mechanical, and electrical work required to refurbish and modernise the existing system.

Work began with the removal of the existing filter media, and the demolition and removal of the existing under drainage system and concrete screed in which it was cast. The central channel of the under drainage system was then constructed from reinforced concrete, allowing for the new parallel lateral system to be installed. All existing valves, actuators, cabling, and hosing were removed and replaced. New actuated valves were installed at the filter outlet, backwash inlet, air scour inlet, and backwash outlet.

Necessary pressure, turbidity, flow, and level sensors were installed, including an ultrasonic level sensor to achieve the control objective of constant filter head (which was not possible with the existing system) by varying the degree of opening of the filter outlet valve. Associated electrical work was also completed including a PLC with HMI control for monitoring the new system which would integrate with the existing SCADA system. New filter media was also supplied to complete the works.