In line with the City of Cape Town Water Strategy – Our Shared Water Future, the City is increasing focus on improving the state of our rivers. This is being done through engineering interventions, improved basic service provision, as well as education and raising awareness.
 
Unfortunately, last week the City experienced faults at the Koeberg Road Sewage pump station, which resulted in interrmittent overflows into the Theo Marais canal, which runs past the Theo Marais Sports Complex/Milnerton Cricket Club and into the Milnerton Lagoon. This has had a noticeable impact on the quality of the lagoon. A clean-up of the Theo Marais Canal downstream of the pump station spill was undertaken on Saturday, 18 April 2020, and remains ongoing.
 
Faults were a result of misuse/abuse of the sewage system, particularly the flushing of cloth rags. Two of the four mechanical pumps at this facility have ceased to function as a result.
 
A third pump has been installed within the past week (Thursday 16 April 2020), which has stopped the overflows, however until the fourth pump is installed, the risk of overflows will remain higher than usual. The fourth pump is expected to be repaired within two weeks. This will allow the City time to source material to repair the extensive damage to the pump impeller, shaft and bearing housing.

City staff have further confirmed that no evidence of a significant die off of fish could be found in the lagoon. Staff removed six barbal from the area. These are freshwater fish, which likely drifted from further upstream. The most likely cause is a sudden instance of excess nutrients in the water, resulting in algal growth which depleted the amount of oxygen available, but this will require further studies to determine with certainty.
 
In addition to repairing the broken pump station, the City has implemented special measures to limit the amount of illicit greywater which flows to the lagoon via the stormwater system by pumping into sewers at strategic points.
 
It should be noted that during this time, weekly samples of final effluent from the City’s Wastewater Treatment Works in the area, namely Potsdam, have shown significant improvement compared to the end of 2019 and the first three months of 2020 when technical issues at the plant caused the quality of final effluent to deteriorate.

Contingency plans implemented on site have produced the following results:

• Sampling on 6 April reflected e. coli counts of 100cfu/100ml
• Sampling on 13 April reflected e. coli counts of less than 10cfu/100ml
• Sampling on 20 April reflected e.coli count of 280cfu/100ml

These are very encouraging results which show our short-term interventions are working, while the broader R1,75bn plant upgrade continues. In terms of recreational water use guidelines, cfu counts of less than 250/100ml in 95% of samples over a given period is considered excellent, while cfu counts of less than 500/100ml is considered good.

Further repairs and upgrades being undertaken on site will improve the plant’s ability to achieve excellent results on a consistent basis.