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The Olifantsvlei Wastewater Treatment Works are being extended to more efficiently treat residential and industrial effluent. In all, there are six wastewater treatment works cleaning Joburg’s water.
THE extension project at Johannesburg Water’s Olifantsvlei Wastewater Treatment Works continues without hiccup.


Project engineer, Russ DoddingOlifantsvlei Wastewater Treatment Works project engineer, Russ DoddingThe R48,4-million construction project started recently and men in shovels and bulldozers can be spotted levelling the ground to prepare for building. The completion date for the civil, mechanical and electrical works is expected to be a little over a year from now, in April 2012.

Once the project is finished, it will consist of bulk earthworks to form new terraces, an activated sludge reactor, flow divider, three clarifiers, concrete and brickwork pump stations, a monitor room, interconnecting concrete, steel pipework and fittings, and another effluent pump.

According to the project engineer, Russ Dodding, the extension will increase the treatment capacity from 160 megalitres a day to 210 megalitres a day.

“The new unit three module three will have a treatment capacity of 50 megalitres per day and has been based on the well-established and optimised treatment process used in unit three modules one and two,” Dodding explained.

The main objective of extending the plant is to provide first-class wastewater treatment works to cater for present and future increase in capacity and to reduce the chances of contaminated water spilling into rivers.

“New initiatives such as launching a full-scale water conservation and demand management plan, building a sustainable infrastructure upgrade, renewal and maintenance programme, enhancing our water quality monitoring and optimising treatment plant processes highlight our continuing commitment to plan for Johannesburg’s future service demands,” explained the City’s executive director for infrastructure and services, Lawrence Boya.

The Olifantsvlei Wastewater Treatment Works is one of six such facilities owned and directly managed by Joburg Water. Through them, the municipal-owned company treats all the domestic sewage and industrial effluents released into its sewers. Between them, these works treat 930 million litres of sewage daily.


Workers preparing the ground for contructionWorkers prepare the ground for contructionThe treatment works are intensively monitored on a daily basis to check the quality of the incoming wastewater, process performance and efficiency and the quality of final effluents and by-products.

Over 2 200 samples are tested each month. In addition, certain key factors are monitored on a continuous basis using on-line analysers. As part of the permit requirements, the upstream and downstream quality of the streams into which treated effluents are discharged are regularly monitored.

Bio-monitoring is also carried out to determine the effect of treated effluents on the surroundings of these streams.

In addition, Joburg Water monitors by remote sensing a number of key places in its sewer network to detect sewer overflows and pump-station failures. To determine the impact of the wastewater treatment works on underground water, 66 boreholes are monitored on a regular basis. A sample of each borehole is analysed monthly for 37 parameters.

One of the ways in which Johannesburg Water interacts with the river systems in and around the city is through its treated wastewater discharge. Considerable improvements have been achieved in the management of its treatment works.

Since 2002, Johannesburg Water has efficiently disposed of sludge, decreasing the amount of pollution entering the city’s rivers, as per national guidelines set by the departments of Health and Agriculture.

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