Water

Emfuleni, South Africa

A water efficiency system known as advanced pressure management reduces pressure in the city's water network, thus reducing the amount of water leaking through small undetected holes.

What is it?

The Water and Sanitation unit of Emfuleni Municipality (Metsi-a-Lekoa) entered into a partnership with the Alliance to Save Energy to address water inefficiency and leakages in two residential areas of the municipality, Sebokeng and Evaton.

The Alliance to Save Energy (ASE) facilitated a performance contract for the implementation of a water efficiency system known as advanced pressure management on the bulk water supply pipeline serving these districts. As a result, less electricity is required to pump water, meaning the municipality reduced its greenhouse gas emissions.

How does it work?

The Municipality of Emfuleni had a critical water supply problem, due to leakages and resultant financial losses. The Sebokeng and Evaton districts were receiving enough water to fill two Olympic-sized swimming pools every hour, but over 80% of this was lost to leakages.

ASE identified advanced pressure management as the solution – by reducing pressure in the network, the amount of water leaking through small undetected holes is reduced. The system is flexible and uses timers to regulate pressure according to demand.

ASE facilitated the signing of a performance contract between the municipality and WRP Consulting Engineers for the installation of system. This contracting mechanism was deemed to be the best approach in light of the municipality’s limited ability to access capital and its lack of technical capacity, to implement, operate and maintain the required infrastructure.

A performance contract is a type of BOOT (Build-Own-Operate-Transfer) contract, with remuneration paid to the contractor through the resulting savings in water purchases from the bulk supplier of water to the municipality. The contract period in this instance is five years.

Next steps

Metsi-a-Lekoa and the Alliance to Save Energy are investigating the potential for further pressure management by dividing the water network area in smaller supply zones so that each one of these areas has its own advanced pressure management system. Active leakage control is also being considered, involving the detection of network leaks using sophisticated underground pipe leak detection equipment.

Application

• Advanced pressure management works best in specific locations: places with high water wastage, high water pressure etc.
• The effectiveness of advanced pressure management is also dependent on the topography of the potential implementation area, working best in locations where bulk water is supplied from a high point to a low point.
• The application of advanced pressure management is much more complex where multiple supply points supply water into a large area. The fewer the supply points, the better (in this case there are only 2 supply points).
• In certain instances more localized (secondary) pressure control stations can also be installed downstream to a large control station where pressures in the network are still high due to undulating topography, but only where it is possible to ring-fence supply into smaller localized and discreet supply zones.

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