Construction will soon start on the R70-mil-lion upgrade of the Wemmershoek wastewater treatment works (WWTW), following a delay owing to environmental issues, reports engineering and environmental consultancy SSI.
The project is one of several in the Western Cape that are in various stages of completion where SSI is involved.
SSI Western Cape sector area manager for water Peter Jordaan tells Engineering News that the design for the Wemmershoek WWTW project has been finalised and a contractor has been appointed.
The project entails the construction of an upgraded five-million-litre-a-day sewage treatment works, a new main transfer sewer pipeline from Franschoek to Wemmershoek and an outfall pipeline to the Berg river. Treated effluent will be pumped back to Franschoek through a separate rising main to irrigate parks and sports fields.
The Wemmershoek plant will be built to the same latest technology standards as the Fisantekraal WWTW project, and will also include a Nereda Aquasuite intelligent controller similar to the one recently installed at the Gansbaai WWTW, says SSI sector consultant for control and instrumentation Alfred Schröder.
These technologies include intelligent motor control and fieldbus instrumentation, as well as the Nereda wastewater treatment technology.
Nereda technology has a much smaller plant footprint than equivalent-capacity conventional plants, and is suited to the Wem-mershoek plant owing to space restrictions, Jordaan explains.
SSI Energy & Resources sector area manager Carl Schneider further adds that the Nereda technology is more energy effi- cient than the membrane bio- reactor (MBR) technology. “Last year, the energy savings of the Nereda plant, compared with a conventional MBR, was esti- mated at R400 000.”
The Wemmershoek project will be completed within the next 20 months, says Jordaan.
Meanwhile, SSI is also involved in the design and project management of a direct water reuse scheme and the upgrade of the Hermanus WWTW to provide 2.5-million litres a day of high-quality treated effluent from the works destined for the area’s drinking water network.
To supplement the drinking water in Hermanus, purified water will be pumped through a new pumpstation and pipeline into the existing clear well at the Preekstoel water treatment works.
Jordaan explains that the extensive and prolonged drought situation in the Cape region has led SSI to reconsider solutions that make the best use of available resources, rather than simply increasing the sizes of reservoirs or storage dams, especially in holiday towns where the popul- ation is increased by holiday- makers only for a few weeks every year.
Meanwhile, the company is also involved in the rehabilitation of the Lourens river at Somerset-West.
A large portion of the Somerset West central business district, as well as various residential areas, falls below the 1:5 year floodline, resulting in regular flooding and associated damage, he explains.
As a result of urbanisation, the river was declared a protected natural environment (PNE) in 1997 to control development activities and reinstate the natural environment. This is the only PNE-declared river in South Africa.
Existing property rights had to be respected and the social implications of widening the river had to be considered, resulting in a challenging project, says Jordaan.
SSI also advised the City of Cape Town on the relocation and upgrade of the scheme’s Flood Early Warning supervisory control and data acquisition system.
Saldanha Bay Electrical Infrastructure Project
In 2011, SSI also developed an electrical infrastructure master plan for the Saldanha Bay municipality, says SSI specialist engineer Barry Reid.
“Developing such a plan involves considering a municipal area’s current electrical infrastructure and determining the area’s growth in electricity demand, both historic and forecast. Further, the company also looks at the area’s population growth, housing plans and electrification progress.”
Information on applications for electricity supply is then collected from the municipality, and from this, SSI develops a 20-year electricity forecast, explains Reid.
The forecast is used to deter- mine how the municipality’s electrical infrastructure can be expanded or upgraded to cater for this demand.
The final report for the municipality was expected to be sub- mitted to the municipality by the end of February.
Morupule Colliery Expansion
SSI Cape Town was subcontracted by engineering design company ADP Projects to undertake the complete electrical, control and instrumentation design on the Morupule colliery expansion project, in Botswana.
The project entails upgrading the existing mining infrastructure, materials handling systems and processing plant capacity to increase coal production from about one-million tons a year to about 3.2-million tons a year, explains SSI Western Cape associate Selvan Murugan.
A tight project schedule presented a challenge and SSI and ADP had to work in tandem to ensure everything was completed on time. The procurement of equipment and the design were under- taken simultaneously, which made a detailed level of design necessary to go out with the procurement information.
The project is in the final stages of commissioning and all systems have been designed and built. It will be complete within the next two to three months, says Murugan.