CAPE TOWN – Some experts are calling on the City of Cape Town to rethink the way it is disposing of human waste.It follows the recent furore surrounding three marine outfall pipes, which pump millions of litres of raw sewage directly into the ocean.
City officials claim the method, which was first implemented in 1901, is both a safe and cost-effective way of dealing with effluent. They quote various studies which show ‘insignificant’ environmental impacts.
The municipality is currently applying for permits via the Environmental Affairs Department to keep using its outfall pipes in Green Point, Camps Bay and Hout Bay. Officials cite financial pressure as one of the major reasons it would prefer to continue pumping untreated effluent out to sea.
While the City cautions that alternative treatment technologies may likely cost ‘tens of millions of rand’, the local authority admits no feasibility reports have been commissioned to explore other options.
Mayoral committee member for utility services Councillor Ernest Sonnenberg says the way forward is clear.
“Ultimately, given the budget constraints the City is faced with and the minimal environmental impact of these outfalls, the argument to allocate precious resources for their upgrade is not strong enough.”EWN requested the City for more details, including statements detailing the current costs involved.
The City made two sediment surveys conducted by the CSIR in 2006 and 2011 available to EWN. The papers conclude the effect on the environment is minimal, based on its analysis of contamination in sediment. The most recent comprehensive impact study was done in 1990.Some experts are concerned the available information is outdated and they are lobbying for the method to be re-evaluated.
Researcher Glen Ashton believes pumping raw sewage into the ocean is no longer justifiable, partly due to growing volumes. According to the City 30 million litres of sewage are discharged through the Green Point pipeline daily. The current volumes at Hout Bay and Camps Bay are 5.5 million litres and 2.2 million litres respectively.
“There’s been a significant increase in human pressure on the environment and the other thing that’s changed obviously is the body of knowledge. We know a lot more about the impacts.”
Ashton says in addition to looming water shortages, new scientific knowledge regarding harmful compounds needs to be taken into account.
“The amount of sewage going through those pipes is enormously more than it used to be and I don’t think one can just carry on operating under the existing paradigm, considering the fact that things have changed so much,” says Professor Leslie Petrik from the University of the Western Cape’s Chemistry Department.
She warns although unsavoury, the sewage itself is the least of our worries since the chemical components commonly flushed down with human waste pose greater long-term health risks which may affect the food chain from the bottom up.
These include caffeine, oestrogen from birth-control pills, and aspirin as well as compounds found in personal hygiene products. Most of these do not make the list of chemicals commonly tested for in impact studies. She warns there are some 87,000 compounds that still need to be studied for their potential dangers.
“We’ve… developed all these new compounds since the original permits were granted. And we have no idea what amount of these compounds are being released into the ocean and what their ultimate effect is going to be,” Petrik explains.
The City counters screening to remove solids, coupled with the length and depth of the outfall pipes, lead to sufficient dispersion and dilution. Petrik is not convinced and cautions we’re probably inflicting damage we do not yet understand.
“What is going out into the ocean is essentially a mixture of your sewage waste, as well as every chemical that you use in the household, or for medicinal purposes, or for cleaning purposes… these other compounds are far more dangerous than the actual sewage, because the sewage will still probably decompose over time, but many of these compounds are very persistent and they accumulate within the environment and once they’re released you can’t recall them back.”
About 120 coastal outfall pipes are operating in South Africa, but anEWN investigation has revealed the Department of Environmental Affairs (DEA) does not know how much waste water flows from them.The most recent estimate dates back to 2008, when some 786 million litres of polluted water was being discharged into South Africa’s oceans daily.
The DEA, which recently took over responsibility for marine outfall pipes, says it is trying to establish the most recent discharge figures while reviewing existing licences.The City of Cape Town’s public participation process ends on 10 July 2015.
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