Sewage still runs into lagoon
Following an article in this newspaper on August 25, referring to raw sewage spilling into the lagoon alongside George Rex Drive, it appears as if the problem has not yet been rectified.
“Sadly, more than a week after this problem was reported, the problem has got worse,” complained a concerned Knysna resident. This resident spoke of an overpowering smell in the vicinity of the waster water works.
Referring to the municipality’s earlier comment on the problem, the resident continued: “I am really disappointed in the municipal response – which is to go into the details of how the system is supposed to work. They have not accepted responsibility for allowing this work to go ahead without proper environmental advice, and for allowing the situation to happen.”
Several reports by paddlers of raw sewage being seen in the lagoon had been tweeted throughout the week.
The resident further expressed that it was “depressing enough to see all the empty shops and houses, try to earn a living, watch the news etc. Now do we also have to deal with failing infrastructure and this pong?”
Municipality responds
Knysna Municipality, SANParks, Eden District Municipality and Aurecon Consulting Engineers held another meeting to address the crises at the Knysna waste waterworks. At the meeting all parties once again acknowledged the problem and evaluated the short- and long-term solutions.
According to Acting Knysna Municipal Manager Lauren Waring, the municipality’s immediate action will be to eliminate the excess seepage currently fouling the Ashmead culvert. “We will be using a vacuum tanker to remove this seepage from the immediate vicinity.”
Waring assured, “This seepage is not raw sewerage. Recent excessive hydraulic loading, along with recent wind and rain has unsettled sediment within the maturation pond which was seeping into the lagoon. The accompanying strong smell of rotten egg, present around the bottom end of Vigilance Drive, is due to gasses released from this mobilised sludge, and not raw sewerage.”
An eye witness to sewage flowing into the lagoon via the culvert under George Rex Drive says, however that he had witnessed not only sewage, but sanitary towels, condoms etc flowing together with “what looked very much like raw sewage to me”.
“This latest incident follows shortly on the heels of the already reported on drop in levels of the bacteria which is used at the waste water treatment works to assist in breaking down effluent, resulting in semi-processed effluent seeping through the filters,” Waring said. “As previously stated, correcting this issue is a time consuming process, which we are committed to completing as soon as possible.”
She further explained that the current municipal waste water treatment works system, which was in the process of being upgraded, had been in use since 1986. “Processing the effluent at our waterworks is a continuous process and the plant is designed to facilitate a constant flow. This makes it very difficult to address the situation as the town’s waste has to continue being processed.”
She further explained that the municipality had been able to bypass the maturation pond from which the disturbed sludge is seeping by reconnecting to the previous system’s oxidation ponds, “While this means that we will be able to clean the maturation pond and is at present a better option than running the system through this pond, this solution, utilising pre-1986 technology, is not ideal.”
“Piping necessary to bypass the old oxidation ponds and convey the product from the settling tanks directly to the final maturation pond where chlorination takes place, has been delivered on site. Unfortunately two different materials requiring a specific bonding agent have to be used and we await delivery of the necessary fittings. We are however confident that this temporary solution will show a visible change to the product leaving the waste water treatment works by the end of this week.”
Waring further reiterated: “I have to stress that this is a temporary solution and that the issue cannot be solved with a quick fix. This issue will only be resolved once the bacteria in the bio-reactor have reached satisfactory levels. Unfortunately the ideal growing circumstances for these bacteria are dictated by factors outside of our control such as the ambient temperature, wind and sunlight.
“We will however be attempting to raise the levels of bacteria through a process called bio-augmenting by which bacteria are added to the system.”
Waring continued: “It must however be kept in mind that as the waste water treatment works have to remain in use, large amounts of water continuously flow into and out of the bio-reactor, which means that even bio-augmentation is not an immediate or long-term solution.”
She said that the municipality had to wait for the bacteria to grow. “In the meantime we will do what we can to ensure that the situation is remedied as speedily as possible and that as little impact as possible is made on the lagoon.”
James McCarthy, assistant chief of Municipal Health at the Eden District Municipality, assured that the estuary would be tested daily. “Both bacteriological and chemical samples will be taken on a daily basis. We will also be taking samples in more locations as SANParks have made one of their vessels available to us.”
SANParks Knysna area manager, André Riley said the organisation is very concerned with the current water quality in sections of the Knysna estuary. “Excessively high bacteriological counts have recently been recorded in the Ashmead channel. These results exceed the acceptable limits for recreational use.
“As the management authority of the lagoon, it is SANParks’ obligation to ensure that the public are notified of any possible health risk arising due to pollution input into the estuary. To this extent, SANParks, Eden District Municipality, as well as the Knysna Municipality are busy exploring communication channels to keep the public informed of any changes in the water quality on a constant basis. The first test results are expected this Thursday,” said Riley.
Knysna Executive Mayor Georlene Wolmarans confirmed the municipality’s determination to fix the problem. “Since we became aware of this problem no effort has been spared in attempting to save the lagoon while still delivering the service of waste water treatment. The problems have been identified, and the solutions have been identified and are in the process of being implemented.
“Although solving the problem permanently will take longer than any of us would like it too, rest assured that we are doing everything we can to speed up the process while minimising the impact in the meantime,” Wolmarans concluded.
Aurecon Consulting Engineers in George were contacted for further comment, but they said that they stand by the municipal explanation for now and would reserve comment until a later stage.
ARTICLE: FRAN KIRSTEN, KNYSNA-PLETT HERALD REPORTER
Source: The Knysna-Plett Herald