Earlier this week the issue of the City of Cape Town’s effluent being pumped into the ocean was brought to the public’s attention. However, the City maintains that this is the most efficient way to get rid of waste.
“This method requires less land and has less impact on surrounding communities, and has little to no impact on coastal recreational areas. This system operates by rapidly diluting the preliminarily effluent to at least a 100:1 at the immediate exit point of the outfall. This corresponds to a 99% reduction in contaminant concentrations in the receiving water, which is far beyond the capabilities of even advanced conventional treatment processes,” said Ernest Sonnenberg, mayoral committee member for utility services.
“Furthermore, in the case of a long marine outfall, bacteria are controlled by locating the outfall so that transport of wastewater to beaches or other water contact areas is virtually eliminated. The outfall is designed so that, in the unlikely event that transport to beaches does occur, the combination of initial dilution, oceanic diffusion, and bacterial mortality reduces the bacteria to very low (safe) levels,” said Sonnenberg.
With regards to whether or not this is a sustainable method of disposal, Sonnenberg noted that the City of Cape Town defers to the Department of Environmental Affairs for guidance. “The current position is that it is an economically viable and environmentally safe alternative to secondary treatment.”
According to Sonnenberg, there is no need to look for an alternative method of sewage disposal at present, “as this method has negligible impact on the environment,” said Sonnenberg.
“Coastlines are regularly monitored to ensure that E.coli from the outfall is not reaching the beach, as such there is very little [health] risk associated with this activity,” added Sonnenberg.
If the public wishes to submit comment, they can email Kevin Samson, manager of Waste Water Treatment at Kevin.Samson@capetown.gov.za.