Cape Town – Effluent leaving the Knysna Water Treatment Works is now compliant, according to the town’s estuary pollution committee.
E.coli water samples taken at the wastewater treatment plant and its outlet had showed a steady decline since red flags were raised about the water quality in February.
The SA National Parks (SANParks) has led the committee this year in partnership with the Knysna Municipality, Garden Route District Municipality, the Breede-Gouritz Catchment Management Agency and the Knysna Basin Project.
In March, water samples taken in the Knysna estuary showed improvement after signage was erected warning recreational users not to fish, collect bait or swim there due to contamination and high levels of E coli.
The municipality had attributed the water quality to a presence of oil and grease at the wastewater treatment works (WWTW).
The Knysna Municipality confirmed there was chemical contamination at its WWTW dating back to February 4, and acknowledged it was a cause for concern.
Knysna Park manager Megan Taplin said: “We are pleased with this progress at the WWTW where E.coli levels are compliant, according to the Department of Water Affairs and Sanitation standards.
“According to South African water quality guideline for recreational use, recreational areas must have an E.coli bacteria level lower than the 500 cfu/100ml mark.”
Cfu stands for colony-forming unit, an estimate of viable bacteria or fungal cells in a single sample.
Multiple interventions by partners led to this positive outcome, SANParks said. The municipality had replaced screens at the WWTW to monitor inflow into the plant.
“This is important to retain solids that could have caused blockages in the system and further improved its functioning. All clarifiers were also recently restored to operation.”
SANPark said that oil and grease samples were now being taken at different times of the day at the WWTW in order to try to pinpoint the businesses that might be contributing to pollution loads.
The committee partners are conducting a pilot survey of the industrial area to gain a better understanding of potentially harmful substances being discharged into stormwater, which may affect the health of the estuary.