Cape Town- A recent meeting held with Milnerton residents over the polluted lagoon left a bitter taste in their mouths, but the City said strides have been made to address the pollution.
Mayco member for water and waste services Xanthea Limberg said: "In a joint operation between multiple City departments the work undertaken in December yielded a positive result. The plan was to help the lagoon cope with the high levels of pollutants, and one of the best ways to do this was to get as much seawater into the system as possible. This, in turn, replicated a healthy natural functioning estuary.
"The wider and deeper lagoon mouth allowed for increased flow of seawater into the lagoon, which is most effective in counteracting eutrophication, or the scenario in which algae is flourishing and consumes all of the oxygen in the water," Limberg said.
"The artificially widened lagoon mouth allowed high-tide ingress into the estuary, and when low tide occurred, the polluted and algae-rich water was naturally drawn out into the ocean."
Recently, the City announced plans to upgrade the Potsdam Wastewater Treatment Works. The completion of the upgrade is scheduled for 2025.
The City said the treatment plant was not the primary cause of the pollution despite residents saying it was. According to the City, there were various sources of pollution. The upgrade of the Potsdam plant will cost R1,7 billion.
Limberg said: "However, it must be understood that reasons for poor water quality are complex and include natural causes such as drought, high temperatures and the closing of the river mouth. Other factors such as cable theft pose a challenge, which is what caused the Table View East pump station failure in October 2019, leading to a sewerage spill.
"Teams have been working to clear hyacinth growth in the river which may have dislodged some of the pollutants from the spill and caused them to flow downstream to the lagoon."
In December an aerial photograph was circulated on social media showing the extent of the pollution. However, residents associated the brown or green colour in the water with sewage, but the photograph that has been widely circulated showed the growth of an algal bloom in the lagoon.
According to the City at any given time, the growth of an algal bloom is as a result of excess nutrients from wastewater, fertilizer, and stormwater runoff that is coupled with lots of sunlight, warm temperatures and shallow, slow-flowing water.
"A range of City representatives met with members of the community on Monday evening and shared progress of plans and investments to alleviate challenges in the catchment, which was followed by a question and answer session.
"This is one of several meetings that have taken place between the City and the community recently, and the City is committed to sustaining a close working relationship with the residents as we drive the projects to improve water quality. We acknowledge the community’s frustration and hope that by keeping channels of communication open that costly litigation can be avoided," Limberg said.
@MarvinCharles17