With Eskom reintroducing load shedding nationally as from this month, the City of Cape Town is installing special safeguards to reduce the risk of sewage spills resulting from non-functioning sewage pumps.
In 2006, the Koeberg power failures affected almost all of the city's 390 sewage pump stations across the Metropole, resulting in sewage pump station overflows.
However, this problem has been reduced significantly by the introduction of telemetry systems and upgrading maintenance schedules, says Sipho Mosai, Director of Water Services.
According to Mr Mosai, most pump stations are equipped with a duty pump and a standby pump.
When one of the pumps malfunctions, it is removed and sent away for repairs (Pumps are either taken out for routine or scheduled maintenance or electro - mechanical breakdown) the standby pump then takes over.
It is at times like these, he said that the pump station is at increased risk for the duration of the repair.
"The city has now implemented contingency plans for future load-shedding and the wet winter season.
"These include the installation of back-up generators for strategic sewage treatment plants, as well as cooperation with the City's Electricity Department to plan power cuts in such a way that sewage flows can be managed and spillage into the environment minimised ," said Mr Mosai.
In addition, the city has upgraded its telemetry system which links the 26 municipal pump stations across the entire Metropole to the Schaapkraal control centre via its base station at the Steenbras Water Treatment Plant.
The system immediately alerts the control centre as soon as it detects a pumpset failure. This enables the centre to mobilise response teams within minutes.
Experience has shown that power cuts for two hours or less do not cause overflow problems.
However, longer blackouts do, as retention facilities at the stations have a limited capacity.
"In the event of a spillage, environmental pollution from our pump stations is usually treated with bio-augmentation material that breaks down harmful substances naturally.
"Health warnings are also posted at water bodies in the city areas where there could be a health risk.
"During sustained power cuts, residents are advised to use water sparingly and to flush toilets only when necessary to reduce the city's volume of wastewater that has to be treated," Mr Mosai said.
Members of the public can also call the 24-hour number at 086-0103-054 to report any sewage spills. - BuaNews
Compiled by the Government Communication and Information System