Milnerton Lagoon, an estuary formed by the Dieppe River, remains highly contaminated four years after the Western Cape Environmental Inspectorate ordered the City of Cape Town to clean it up. Archive photo: Steve Kretzman
The stench of sewage from Cape Town's Milnerton Lagoon is not new, but residents say it has become nauseating in recent weeks. This is despite the state government ordering the city to repair the highly polluted lagoon more than four years ago.
Residents who live near the lagoon have described the stench emanating from the lagoon since late last month as “eye-opening” and nauseating.
Asked about the cause of the sewage contamination in the lagoon, Zahid Badrudeen, Mayco's member for water and sanitation, pointed to a breakdown in the sewage infrastructure since July, as reported by GroundUp to Milnerton residents and councilors. It referred to a letter outlining the city's intervention to address the resulting pollution.
The letter, dated Nov. 29, said the city had received complaints about “foul odors” in Milnerton “for the past few weeks.” This was due to a “series of events” that “compromised the integrity of the sewerage system” and the issue was being addressed.
The letter explains that there were sewer line collapses in July, August and September, all of which caused sewage to flow into the lagoon through storm channels.
Repair work in October also caused sewage to overflow into storm channels and flow into the lagoon.
The city explained the current state of remediation and efforts to contain the sewage flow, apologized for the “significant inconvenience” and said, “We are working diligently to address the root causes of the contamination and prevent future occurrences.” We are working on it,” he said.
Sewage treatment failure
The Potsdam Wastewater Treatment Plant (WWTW) discharges more than 40 million liters of sewage effluent per day into the Dieppe River, just 5 km upstream of the lagoon. This is the main flow of fresh water that enters the lagoon in summer. If the Potsdam sewage treatment plant had properly treated the sewage it received before releasing it into the river, the pollution would not have occurred.
Among other contaminants, sewage contains Escherichia coli and enterococci, bacteria known as fecal coliforms that are present in the human intestines. National guidelines state that the colony forming units (cfu) of fecal coliform bacteria in treated wastewater should be less than 1,000 per 100ml. This is also true for the 'target' range of intermediate contacts in the city's rivers, flies and estuaries. In other words, you should be able to canoe and kitesurf in properly treated wastewater released from sewage treatment plants without any negative effects.
Badrudin said the pollution was not caused by World War II in Potsdam.
However, according to the Department of Water and Sanitation's (DWS) regulatory information system, only 3% of the monthly wastewater quality tests conducted at the Potsdam WWTP over the past year met minimum wastewater quality guidelines.
Additionally, Potsdam has achieved chemical compliance in only 48% of its wastewater tests so far this year. This is the measurement of elements such as nitrogen, phosphate, and ammonia. It also achieved only 31% physical compliance, which measures aspects such as suspended solids, pH, and electrical conductivity. Currently, the DWS system lists the water quality of Potsdam's wastewater as “poor.”
Over the past 20 months, the city has been implementing a R5.2 billion refurbishment of Potsdam WWTW, with completion scheduled for the end of 2027.
Asked about the poor quality of the drainage water, Badrudeen said the final results of the renovation would be known “only once all components are constructed.”
“To address the current challenges, some infrastructure components are being rapidly developed and are expected to be completed by mid-2025, leading to significant improvements in the quality of treated wastewater.” he said.
He said wastewater compliance has “already improved to 75%.”
However, the DWS information system has revealed nine “high-level failures” this year, the most recent being on October 29th.
water quality results
To the city's credit, the city makes the results of inland water quality tests publicly available through its public inland water quality dashboard. The results also show that the main source of sewage pollution in the lagoon comes from the Potsdam sewage treatment plant.
According to the city's water quality data, results at testing sites immediately downstream of the Potsdam WWTP were, on average, worse than water quality results upstream of the WWTP. The latest water quality test results (November 19) show an E. coli count above Potsdam WWTW of 29,100 cfu/100 ml, which is more than 11 times the allowable limit for intermediate contact. However, the count downstream of Potsdam WWTW was 7.3 million cfu/100 ml. This indicates a serious source of contamination, most likely coming from sewage treatment plants.
Carolyn Marx, an environmental activist, Milnerton resident and member of the Mayor's Advisory Committee on Inland Water Quality, said the results showed significant sewage contamination was coming from either the Potsdam sewage treatment plant or the sewer pipes leading to Potsdam. He said that it shows.
Marx said on November 27 that the stench from the lagoon was so bad that it burned his eyes. When GroundUp spoke to her on December 3, she said the lagoon was still emitting a foul odor.
She said there is little to no rain this time of year, and most of the flow to the lagoon comes from the sewers.
Compared to the 40 million liters of wastewater released per day from Potsdam, it would take “vast amounts” of sewage coming from other sources to pollute the lagoon to this extent.
But whatever the source, she said all the measures the city is taking to prevent pollution of the lagoon appear to be insufficient.
green scorpions command
Following a warning to stop pollution of Milnerton Lagoon, Green The state's environmental compliance officer, known as Scorpion, issued the directive to the city. A clean-up of the lagoon was ordered in September 2020.
Directives are enforceable notifications issued under the National Environmental Management Act.
The city's inland water quality dashboard shows significant pollution in the lagoon in 2019, improving in late 2020 and 2021, but worsening from 2022 to the present. Results in 2024 were on average worse than those in 2019, which led to the issuance of the directive.
Western Cape Department of Environment, Development and Planning spokesperson Rudolf van Jaarsveld said the directive was in force and the city was liaising with the provincial government on some of the terms of the directive.
“Some conditions are [of the directive] The City has communicated this to the Western Cape Government as it is subject to future deadlines and a lengthy procurement process,” Van Jaarsveld said.
He said renovations to the Potsdam sewage treatment plant and Koeberg pumping station would “prevent further pollution from these facilities.”
He said compliance with the directive and the city's reporting on this issue continues to be monitored.
But Milnerton Canoe Club chairman Richard Allen said the condition of the lagoon appeared to be worsening. More experienced canoe club members were paddling in the lagoon four years ago when state officials issued the directive, but Allen said they have since stopped all paddling in the lagoon. He said club members are currently rowing along a canal in Century City, about 5 kilometers away. He said they are fighting to keep the canoe club alive.
He said the lagoon's water quality was “gradually deteriorating”.
“It’s toxic and stinks to hell,” he said.
He said the smell coming from the water was “terrible” at the end of November.
Several events were scheduled at the clubhouse on the shores of the lagoon, but the water was “really dirty.” “I almost threw it.”
Marx told GroundUp on Dec. 10 that the stench diminished because storm surge washed out the lagoon and “suddenly everyone jumped in to try and fix the problem.”
This article was first published ground up
