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City responds to ‘Bay of Sewage’ video<figure class="figure-credits right"><img class="responsive" alt="placeholder" src="http://resource.capetown.gov.za/cityassets/Media%20Centre/water%20quality%201.png" style="width:635px;" /><figcaption> <p>© City of Cape Town</p> </figcaption> </figure> <p>The City of Cape Town has been made aware of a recently released video on Youtube entitled ‘Bay of Sewage’. The video asserts that the Camps Bay long sea effluent outfall off the coast of Camps Bay is ‘killing our coastline’ and ‘starting to harm us’.</p><p>The City recognises that civil society action and pressure is an essential component of democracy and governance and welcomes the focus and passion by individuals and stakeholders on the matter of healthy and unpolluted ocean environments. However, the City holds the view that along with that right is the essential commensurate responsibility of accountability in ensuring that information presented to the broader public is factual, correct and not sensationalised.</p><p>The ‘Bay of Sewage’ video provides no substantive data or measurable science to support its extensive claims. The City, on the other hand, has been monitoring the impact of the outfalls and coastal water quality in general for many years. The City is in the process of completing an extensive 12-month study with the Council for Scientific and Industrial Research (CSIR) on the outfalls which is close to completion and which will in due course be made public. The City is confident that this CSIR analysis will demonstrate once and for all that the marine outfalls are not impacting on Camps Bay in any manner to the extent as suggested by Mr Jean Tresfon in the documentary. However, with the peak summer season upon us and the release of the video, the City now needs to respond directly to the claims made in the video in the public interest, and will use available data to do so.</p><h3>Context</h3><p>The City operates three marine outfalls as a means of sewage disposal and has done so for the last 30 years. These outfalls service the Sea Point area (the Green Point outfall), the Clifton and Camps Bay area (the Camps Bay outfall) and Hout Bay (the Hout Bay outfall). Prior to release, all waste moves through a 3 mm screen which removes all solids and general litter/detritus from the waste stream, which is then disposed of at a land-based disposal facility.</p><p>The outfalls themselves make use of a diffusion system at the end of the undersea pipeline which rapidly dilutes the effluent to at least 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. The distance of the outfalls from the coastline then ensures that bacteria dies off before it can come into contact with humans, as will be demonstrated below.<br><br>All coastal cities globally use outfalls as a means of disposal and scientific consensus has been that the strategy of wastewater disposal through an outfall with preliminary treatment is a safe, affordable, effective, and reliable solution that is simple to operate and has only minimal environmental impacts.</p><p>The City of Cape Town is an urban environment of approximately 4 million people, and as such the daily human waste produced is substantial. Various components of this waste, regardless of the method of disposal, eventually find their way into our environment. As humans, we do not tread lightly on this earth and each of us contribute daily to this waste stream. The City continuously works to dispose of that waste in a manner that is most environmentally appropriate and which will have the least impact on human health. However, any expectation that we as humans do not pollute our environment in some way is not realistic, practical or achievable.</p><h3>Do the marine outfalls have an impact on our beaches?</h3><p>The City has monitored over 100 sampling points across our 300 km of coastline for the last 30 years. In accordance with international and national practice, water samples are collected and measured for E. coli and Enterococci. Further, during each summer period of December to March our qualified Blue Flag beaches are additionally measured by an external service provider (in this case the SABS) on a weekly basis and the results submitted to WESSA. This goes above and beyond the Blue Flag monitoring requirements.</p><p>As it relates directly to both Camps Bay and Clifton, both beaches have successfully retained Blue Flag status over many years. This would not be possible were the outfalls having any substantial impact on our inshore water quality. Further, the City’s own 30-year database shows no discrepancy between the results we get at these two beaches as opposed to beaches situated in False Bay.</p><p>The marine outfalls operate continuously and if they did have an impact on the beaches as claimed in the video, we would see this in the water quality results continuously. This is not the case.</p><h3>Does additional treatment mean that inshore water quality will improve?</h3><p>Sydney, Australia actually moved from tertiary treated sewage with near-shore effluent systems to primary treated marine outfall-based systems in the early 1990s which substantially improved their beach water quality as shown in the graph.</p> <figure class="figure-credits left"> <img class="responsive" alt="placeholder" src="http://resource.capetown.gov.za/cityassets/Media%20Centre/camps%20bay%20sampling%201.png" style="width:604px;" /> <figcaption> <p>© City of Cape Town</p> </figcaption> </figure> <p>What about the plumes as seen in Jean Tresfon photographs and in the video?<br>We expect to see these plumes on a regular basis and in fact they demonstrate that the outfall is working as it is designed to work. Highly defused wastewater released through the diffusers is less dense and warmer than the salty cold sea water and therefore rises in what as known as the ‘mixing zone’. This is the plume that, at times, is visible. It is in this mixing zone that the effluent begins to dissipate rapidly in the ocean water column.</p><p>Do we have data to substantiate this?<br>As part of the CSIR report (that is under way) 14 water sampling points in an array above and around the marine outfalls are tested. These are shown as the flags in the marine chart.</p> <span> <figure class="figure-credits right"> <img class="responsive" alt="placeholder" src="http://resource.capetown.gov.za/cityassets/Media%20Centre/camps%20bay%20sampling%202.png" style="width:576px;" /> <figcaption> <p> © City of Cape Town</p> </figcaption> </figure> <p>To demonstrate how the outfall system works, we have applied a set of results to that array on a day when the plume reached the surface. As would be expected when the plume reaches the surface directly over the outfall, the water sample collected had high counts of E. coli and Enterococci (shown as a red circle). However all of the other sample points showed results below 20 cfu/100 ml for both E. coli and Enterococci (shown as green circles) indicating the rapid dissipation as expected and for which the outfalls were designed.</p> <p>Do we ever get results outside of the national standards?<br>On occasion we do get sample results that are outside of the national standards for coastal water quality.</p> <h3>Are these as a direct result of the marine outfalls?</h3> <p>The evidence says otherwise. Both E. coli and Enterococci, the indicator species used, occur naturally in our environment and are also introduced into the beach environment via multiple sources, some point-source, and some non-point source. Point-source pollution refers to any single identifiable source of pollution from which pollutants are discharged, such as a sewage leak close to the shore or into the stormwater system, whereas non-point point source refers mainly to pollution caused by rainfall washing natural and human-made pollutants from the urban environment and finally depositing them into the coastal waters.</p> <p>We also, from time to time, like any other city, experience infrastructure failures such as pipe bursts. When this happens we will see a discrete and short-term impact on the environment which recedes once the infrastructure is repaired.</p> <h3>What if I notice a yellow/brown foam, or if the water looks brown?</h3> <p>We often have strong wave action on our beaches which, when it occurs, releases many nutrients and proteins from algae and decomposing kelp common in a healthy and productive marine ecosystem such as ours, which in turn increases natural bacterial counts as well as produces a yellowish surface foam. This foam is often misconstrued as sewage, which it is most certainly not.</p> <p>In the past, diatom (algal) blooms have also led people to believe that there is sewage in the water. Carte Blanche sensationalised the issue in 2015 when they showed footage of a naturally occurring ecosystem diatom bloom in their documentary – see the screen grab below. This is not sewage but a healthy normal diatom bloom in False Bay.</p> <span> <figure class="figure-credits left"> <img class="responsive" alt="placeholder" src="http://resource.capetown.gov.za/cityassets/Media%20Centre/false%20bay.png" style="width:436px;" /> <figcaption> <p> © City of Cape Town</p> </figcaption> </figure> <p> <br>What does the video show or say that is incorrect or misleading?<br><br>1.    It states that the limit for Enterococci is 50 cfu/100 ml</p> <p>South African Guidelines for Coastal Marine Waters (90th percentile) ≤185 Enterococci and ≤500 E. coli counts per 100 ml and International Blue Flag criteria specifies (95th percentile) 100 Enterococci and 250 E. coli counts per 100 ml.</p> <p>2.    Footage is shown that suggests the plume is reaching the beach</p> <p>The picture below taken from their video demarcates the expected plume and separates out the foam that is also expected on high surf days. The two are quite distinct from each other. The wave action around the rocks indicates that the footage was taken on a high surf day as the next picture shows a low surf day and no or little white water around the rocks</p> <span>​<figure class="figure-credits right"><img class="responsive" alt="placeholder" src="http://resource.capetown.gov.za/cityassets/Media%20Centre/false%20bay%201.png" style="width:488px;" /><figcaption> <p> © City of Cape Town</p> </figcaption> </figure> </span></span></span> <p>3.    The video suggests that it is only through the outfalls that we contaminate our environment with chemicals, etc.</p><p>As stated earlier, the only way to not allow those chemicals and waste products (such as antibiotics, etc.) into our environment would be to stop using them. No wastewater treatment process removes all bacteria and viruses, and no treatment exists that is effective in removing all heavy metals or chemicals.</p><p>4.    The outfalls are illegal in terms of the Municipal Planning Act.</p><p>This is not correct. The City is currently reapplying for a new type of licence which has been recently introduced. While this application process is under way, the outfalls remain licensed under the original licence are not illegal.</p> <span> <figure class="figure-credits left"> <img class="responsive" alt="placeholder" src="http://resource.capetown.gov.za/cityassets/Media%20Centre/false%20bay%202.png" style="width:535px;" /> <figcaption> <p>© City of Cape Town</p> </figcaption> </figure> <p>5.    The implication that pollution in these areas must be due to the outfall.</p> <p>While there is very little evidence to suggest contamination due to the outfalls, there is a strong correlation between the presence of stormwater outlets and poor water quality across the coastline. This is why signs are posted near stormwater outlets that cross the beach to warn beach users that water may be contaminated.</p> <p>6.    The water quality information they have provided is NOT from the open ocean – these are surf zone results that can be highly impacted by beach conditions and factors such as stormwater runoff</p> <p>7.    It is during the northwest onshore winds that ‘sewage’ reaches the shore.</p> <p>In fact, were the sewage to reach the shore, one would expect that to occur during the southeast driven upwelling which draws deep offshore water into the bay – hence the freezing summer waters.</p> <p>8.    They state that at Camps Bay the outfall is situated inside the bay.</p> <p>This is also not correct and was designed in accordance with coastal engineering standards and falls outside of the pocket beach of Camps Bay</p> <p>9.    The capacity of the outfalls has been exceeded.</p> <p>The pipeline was designed to handle significant increases in volume. The fact that it was designed many years ago has no bearing on its ability to function.</p> <p>Finally, recently another external stakeholder group called Water Watch SA has launched a public platform in Facebook accessible to all. This group is undertaking their own independent E. coli water testing. Their most recent data collected and shown on their Facebook page shows the following results for E. coli on 23 November 2016:</p> <ul><li>40 cfu/100 ml on Clifton 4th Beach</li><li>0 cfu/100 ml on 2nd Beach</li><li>0 cfu/100 ml in front of the pump station on Camps Bay Beach</li><li>121 cfu/100 ml on the southern end of Camps Bay Beach</li></ul> <p>These results would simply not be possible if the marine outfalls were impacting on the beaches as claimed in the video.</p> <h3>Summary</h3> <p>The City does operate three outfalls. These do, like all waste streams, have a measurable impact on our environment. This is unavoidable. However, extensive data shows that with regard to the marine outfalls, the impact is localised to the plume area and does not have an impact on the associated beaches outside of accepted national and international standards and limits.</p> <p>These two beaches meet national and international standards for coastal recreational health guidelines and on the very rare occasion that they don’t this is due to a transitory and discrete event, most likely associated with a land-based pollution source.</p> <p>We are an extraordinary city with the most wonderful coastline for all to enjoy. As we approach the peak of our summer season, the City would like to encourage everyone to enjoy the coastline. Recognising the possible harm that this video may have done in terms of confidence in using the water at Camps Bay, the City will sample and analyse the water daily for the next seven days and provide a follow up communication on the results to reassure all that our beaches are of the highest standard.</p> <p> <strong>End</strong></p></span>2016-12-06T22:00:00ZGP0|#1d539e44-7c8c-4646-887d-386dc1d95d70;L0|#01d539e44-7c8c-4646-887d-386dc1d95d70|City news;GTSet|#62efe227-07aa-45e7-944c-ceebacca891dGP0|#b835b4b5-77f2-4cab-8d4f-b19bcc21c5df;L0|#0b835b4b5-77f2-4cab-8d4f-b19bcc21c5df|Camps bay;GTSet|#2e3de6c1-9951-4747-8f53-470629a399bb1

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