KNYSNA NEWS - Authorities have instituted multiple interventions to probe and address sources of pollution in South Africa's number one biodiverse waterbody, the Knysna Estuary.
SA National Parks continues to test the quality of water through deepwater sampling. Results show all deepwater channel sites have low E. coli levels, except for the Ashmead and Thesen Island inlets which are noncompliant.
The latest samples taken by Garden Route District Municipality (GRDM) indicate that the Bongani, Bigai, Long Street, Station and the Knysna Angling and Diving Association culverts are noncompliant, with E. coli readings above the department of water affairs' acceptable limits for recreational use.
Ongoing interventions
The intervention to find the source of oil pollution which affected the wastewater treatment works (WWTW) is ongoing although oil was reduced considerably in the system subsequent to the introduction of an oil-eating bacteria. Letters requesting restaurants to provide proof of their oil and fat disposal mechanisms were completed. Recent oil and grease tests show a drastic decrease in levels at the WWTW.
The municipality also removed residual oil and grease in sumps. This has brought on a subsequent recovery of the WWTW so that its functioning has improved.
A positive move by the municipality is the replacement of screens at the WWTW. This is important to retain solids that might cause blockages in the system and will further improve the functioning of the system. All clarifiers have recently been restored to operation.
New pollutants
Although functioning has improved significantly, the WWTW is subject to disturbance from any new pollutants that may enter, which may lead to pollution of the estuary. Such pollutants include those found recently in the system such as blood, dye, lime and oil. Citizens and businesses are requested not to pollute sewers and not to dispose of substances in culverts. The "polluter pays" principle will be followed in such cases.
Authorities will convene a workshop within the next week to identify and understand pollutants – and their sources – going into the system from the industrial area which could land in the estuary.
The district municipality continues to take E. coli samples at 14 points around the estuary, and results are posted on Knysna Municipality's website.
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