Brannon Meyer, Tokai
There is something that has been bothering me for many years, with the current water crisis it has become more of a concern.
If I mentioned “electrolytic corrosion of the bulk water supply pipelines feeding Cape Town and environs” it would most probably mean very little, so allow me to try and contextualise it briefly.
Electrolytic corrosion occurs when a steel structure or any buried structure containing steel for reinforcing, like water pipelines, is installed in an area where the salts, minerals and moisture in the ground form a electrolyte, creating a local cell (much like a motor car battery), the circulating current in this area eats away the steel until the water pipe bursts, wasting millions or thousands of litres of water unless appropriate protection is implemented and “regularly monitored”
Areas along the Bulk Water Pipeline Reticulation System supplying Cape Town and environs was identified and in most instances “sacrificial anodes” were electrically connected to the pipelines. This allowed the circulating current a direct path via the pipeline to anodes.
The anodes would be eaten away instead of the water pipeline thus the term “sacrificial anodes”
One of my mandates while employed by the City of Cape Town prior to retirement was to design specific systems to protect submerged structures and conduct regular electrical measurements and inspections of all electrolytic corrosions protection systems.
The reasons were twofold – to monitor the effective functioning of the systems, and to ensure timeous replacements of the anodes before they were completely eroded.
It does not matter how full or empty the dam levels are, if the bulk water supply pipelines are not in a condition to carry water to various treatment plants for local distribution, the dam levels are superfluous.
On my behalf and that of other ratepayers, could you ask mayoral committee member Xanthea Limberg the following:
1. Are these tests and inspection still being carried out?
2. In which areas are they being done?
3. If they are not being done, what has changed that has made this worldwide practice redundant? (There has possibly been some major advancements since my retirement)
Xanthea Limberg, mayoral committee member for informal settlements, water and waste services, and energy, responds::
There is something that has been bothering me for many years, with the current water crisis it has become more of a concern.
If I mentioned “electrolytic corrosion of the bulk water supply pipelines feeding Cape Town and environs” it would most probably mean very little, so allow me to try and contextualise it briefly.
Electrolytic corrosion occurs when a steel structure or any buried structure containing steel for reinforcing, like water pipelines, is installed in an area where the salts, minerals and moisture in the ground form a electrolyte, creating a local cell (much like a motor car battery), the circulating current in this area eats away the steel until the water pipe bursts, wasting millions or thousands of litres of water unless appropriate protection is implemented and “regularly monitored”
Areas along the Bulk Water Pipeline Reticulation System supplying Cape Town and environs was identified and in most instances “sacrificial anodes” were electrically connected to the pipelines. This allowed the circulating current a direct path via the pipeline to anodes.
The anodes would be eaten away instead of the water pipeline thus the term “sacrificial anodes”