Ongoing efforts to reduce load-shedding impact on water and sanitation infrastructure

22 May 2022

The City’s Water and Sanitation Directorate has been implementing ongoing measures to reduce the impact of load-shedding on its infrastructure to ensure that water and sanitation services continue as optimally as possible when the lights go off.

Know your water and sanitation infrastructure:

Sewage pump stations are an important part of the sewer network. The majority of the system works on gravity, but in cases where the sewage must flow uphill, pump stations maintain the flow to wastewater treatment plants.
26 Wastewater Treatment Works (WWTWs) ensure that sewage/wastewater coming from homes, businesses and industries, entering the works (also referred to as influent) is treated optimally for reuse purposes and to be released (also referred to as effluent) into the environment via our waterways.
The City is progressing well to reach the target of replacing 26 000 meters of pipeline to carry sewage/wastewater from homes, businesses and industries to sewer pump stations and WWTWs by the end of June 2022.

Water is purified at 12 water treatment plants. Each of them has an on-site laboratory where drinking water is tested every two hours- every day of the year.
Water flows through the 10 800km network of pumps, reservoirs and pipelines to get to our taps.

Water and sanitation infrastructure such as water and sewage pump stations, wastewater treatment works as well as water treatment plants all require electricity to function correctly. Without electricity, it will not be able to operate.

For this reason, the City has been actioning various measures to help navigate the challenges posed by load-shedding on its operations.

Permanent generators have been fitted at all wastewater treatment plants, 85 larger priority water and sewer pump stations were fitted with permanent generators as a measure to increase the resilience of water and sanitation supply systems.
Some smaller sewer pump stations may overflow when the power goes off so they have been fitted with early warning telemetric alarm systems. This assists maintenance staff in preventing or reducing overflows by using mobile generators to power the pumps. The City has budgeted over R 5,7 million for the telemetric system for the period 1 July 2019 to 25 April 2022. However, with severe load-shedding i.e. large areas without power, it is not logistically possible to prevent overflows entirely, in which case the operational teams do their utmost to contain and clean up such flows.
Most of the City’s water supply is gravity-fed from higher-lying dams. The water treatment plants and critical pumping stations are equipped with standby generators to ensure that clean drinking water can continue to be provided in the event of load-shedding. Some higher-lying areas may experience low pressure or supply disruptions in the event of a power outage affecting the local pump station.

Control Systems in place

Out of the 487 sewer pump stations, the City is planning to upgrade its top 20 critical pump stations. Work is currently underway to assess more pump stations that would require upgrades in a phased approach over the coming years.
The City is installing and engineering a new redesigned Supervisory Control and Data Acquisition (SCADA) system at Reticulation Pump Stations and Waste Water Treatment Works which monitors and adjusts the pumping system to ensure that we operate as energy-efficiently as possible.
Newly installed temperature and vibration detection equipment is used to monitor the condition of the pump sets. The components feed into the SCADA system and the data is logged for review by the maintenance staff. The data then provides the maintenance staff a predictive glance into the condition of the equipment, allowing for maintenance work to be planned and budgeted for more efficiently.

In addition, should recreational water bodies or beaches be detrimentally impacted by such sewage spills, the City takes steps to close the water body and alert users about possible health risks by erecting signage and other appropriate communication. Residents are however urged to remain proactively cautious and take steps to avoid entering potentially contaminated water bodies until the extended load-shedding period is over.

‘Load-shedding affects residents and businesses alike. As a City, we need to ensure that our water and sanitation services continue to operate as optimally as possible and the impact on the environment is prevented or reduced to a minimum as far as possible. For this reason, we have been implementing these measures and ensuring we have the necessary resources available to navigate the challenges caused by load-shedding as much as possible,’ said Councillor Zahid Badroodien, Mayoral Committee Member for Water Sanitation.

End

Published by:
City of Cape Town, Media Office