Sharp, sudden downpours of rain have been blamed on incidents of silt pouring into properties in Craigieburn from the Biggarsberg waterworks.
Residents who spoke to the Courier complained of thick mud being dumped onto their properties, and in some cases even endangering animal and human life.
“The thick mud is like quicksand, and can trap a person,” said one resident. The incidents were reported to uThukela Water, under whose control the waterworks fall.
Hannelie Hickley, Acting Senior Manager for Operations and Laboratory Services, confirmed that residents had complained, but denied that the material was ‘sludge’.
“Our reservoirs store clean potable water. There are sludge drying beds and a sludge dam, which receives the effluent/de-sludge process water from the plant. The automatic de-sludge water from the clarifiers flows to the two sets of sludge drying beds. The beds are operated whereby the flow is controlled to ensure the sludge (solids) settles on the drying beds, and the cleaner overflow water flows into the natural stream. The sludge dam was constructed to contain the settled material that was removed from the raw water, balancing dam at the plant inlet when it is cleaned out and relined.
“An investigation was done after receiving the complaints, and the following was found.
“A complaint from the first resident downstream of the plant was received a day after a severe storm occurred – 34mm of rain was received in an hour at the plant site on February 5. “This volume of rain and wind caused the sludge dam to overflow, and disturb the sludge drying bed operations, and the suspended solids would have been disturbed, washing into the stream below. On January 31, 45mm of rainfall was recorded at the plant. Any normal operations were affected by this volume of rainwater, and this would have had an impact on the overflow water quality flowing into the natural stream. :