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Data shows we’re in deep sh*t

  • Latest Green Drop report papers over the ecological devastation caused by wastewater treatment failure
  • The widely hailed resuscitation of the Green Drop report reveals the extent of South Africa’s wastewater treatment failure, but data shows the situation is even more dire

The long awaited Green Drop report paints a bleak picture of sewage treatment failure across South Africa. More than half of all wastewater treatment works fail to treat sewage properly – and in many cases fail to treat it at all – before pouring billions of litres of it into rivers and oceans every day. But as catastrophic as this failure is, an examination of the underlying data reveals even some of the few treatment works the Green Drop report states are functioning well, are polluting our environment.

The latest Green Drop report released on 30 March after a nine-year hiatus, reveals wastewater compliance, bad to begin with, has plummeted in the intervening years. Of 850 municipal wastewater treatment works, 334, or 39%, are in a critical state, obtaining a score of 30% or less. The number of critical treatment works listed in the last report in 2013, was 248.

“This decline is at both the treatment and sewer collection levels,” states the report. Thus it is not just that wastewater treatment works are failing to properly treat sewage before releasing it back into the environment, much of it is spilling into the environment before even getting to the treatment works.

The average Green Drop score across all provinces was 49,9%, indicating more than half our raw sewage and industrial waste is not being treated to standards which are already inadequate, according to scientists in the fields of chemistry and epidemiology. The average score in 2013 was 60,6%.

As Affiliated Professor in the Centre for Environmental Management at the University of the Free State, Anthony Turton states, this represents “a tsunami of human waste inundating our rivers and dams, without respite, for more than a decade”.

But analysis of the Department of Water and Sanitation’s (DWS) own data shows even some of the few wastewater treatment works that received certification for obtaining scores of 90% or more, are polluting the environment.

Key to understanding this is the acronym NMR, which stands for No Monitoring Required. It is not reflected in the national Green Drop report, but is found in the individual provincial reports.

The Green Drop score

Green Drop scores for wastewater treatment works and the sewerage infrastructure servicing them are obtained using an equation in which weightings are given to five key performance areas: capacity management; environmental management; financial management; technical management; and effluent and sludge compliance, which, at 30%, has the highest weighting.

The report notes: “The effluent quality must comply to 90% (in total) with the authorised limits for the respective categories.”

There are three effluent quality indicators: microbiological compliance, indicating the concentration of faecal bacteria such as E.coli and enterococcus in the water; chemical compliance, indicating the concentration of chemicals such as nitrates and phosphates which negatively impact ecosystems; and physical compliance, indicating turbidity, electrical conductivity, and oxygen demand. The minimum compliance levels are set out in the wastewater treatment works’ authorisation issued by the DWS.

No Monitoring Required means a wastewater treatment works is exempt, according to its authorisation, from having to comply with all or some of these effluent quality indicators.

Five of the 22 Green Drop award winners fall into this category. All of these are in the Western Cape, which obtained 12 Green Drop awards.

Most notable are the Greenpoint and Hout Bay wastewater treatment works in the City of Cape Town, which are in fact marine outfalls. The only treatment the raw sewage – containing pharmaceutical and light industrial wastewater in the case of Greenpoint – receives before being pumped about 2km into the ocean, is maceration through a 3mm sieve to remove solids and grit.

Neither of these are required to monitor or reduce the faecal bacteria in the wastewater before releasing about 30 million litres of essentially raw sewage into the ocean per day.

Questions on the Green Drop scoring for these and other award-winning wastewater treatment works which data shows failed effluent quality standards, received no response.

Ocean pollution

Following research conducted by Edda Weimann in 2013 which found Clifton beach contaminated with faecal bacteria, media reports and a public outcry over the marine outfalls led to the City of Cape Town commissioning its own report.

Conducted by the Council for Scientific and Industrial Research (CSIR) in 2017, it found “no immediate ecological disaster” was imminent as a result of effluent discharge from Cape Town’s marine outfalls. However, the report stated there was “indirect evidence from faecal indicator bacteria counts in seawater samples collected at many sites along the Cape Town shoreline over an extended period that effluent is possibly, even if infrequently, reaching the shoreline”.

The CSIR report further stated that although sewage outfalls are common in coastal cities around the world, “the world cannot use the marine environment as a waste receptacle in perpetuity and opportunities for improved and economically and environmentally feasible wastewater treatment, and the feasibility of using alternate strategies for disposing of wastewater to the marine environment should be investigated by the City of Cape Town (and other municipalities).”

The City has stated it has no plans to divert wastewater disposed via the marine outfalls to wastewater treatment works.

Independent research led by Senior Professor Leslie Petrik at the University of the Western Cape’s Chemistry Department in 2017 to determine whether sewage pollution was affecting seawater and marine organisms, found occasions when E.coli counts near the outfalls that were thousands of times above the general limit for treated wastewater effluent.

But beyond bacteria such as E.coli, and the nitrates and phosphates which are supposed to be removed during wastewater treatment, Petrik et al state sewage contains chemicals of emerging concern which current wastewater treatment methods, when applied, do not remove.

There are thousands of these synthetic chemicals, found in pharmaceuticals, personal hygiene products, pesticides, and industrial applications. These are stable compounds which do not break down in the environment, but accumulate.

Petrik and her colleagues tested for 15 of them in the area surrounding the Greenpoint marine outfall. They included diclofenac (an anti-inflammatory drug commonly known as Voltaren), sulfamethoxazole (antibiotic used for a variety of infections), phenytoin (a medication used to prevent seizures), carbamazepine (a medication for epilepsy and bi-polar disorder), lamivudine (used to treat Hepatitus B infection), and acetaminophen (commonly known as paracetamol).

These were all found to be present in wet sea sand, and accumulating in marine organisms such as seaweed, sea urchins, starfish, and limpets.

Further studies found some of these chemical compounds accumulating in fish in False Bay. False Bay receives effluent either directly or indirectly from seven wastewater treatment plants, none of which received Green Drop certification awards.

Effluent flows into False Bay from the waste water treatment works at Strandfontein. Nearly half of the 49 water quality monitoring sites in False Bay were rated as having ‘poor’ water quality, including popular swimming and surfing beaches. Photo: Steve Kretzmann/WCN

Contender status masks sewage treatment failure

Further clouding the picture is the Green Drop report’s introduction of the contender awards. These are given to wastewater treatment works which fulfil all criteria, but are disqualified from receiving a 90% score (the minimum for a certification award) because they fail to treat the effluent to minimum standards.

Contender status was awarded to 30 wastewater treatment works in the country, giving the impression their environmental impact is acceptable. However, eight of them failed dismally when it came to effluent quality, cumulatively releasing billions of litres of partially treated sewage into their catchments.

This includes, in the case of the Potsdam wastewater treatment works in Cape Town, into an ecologically sensitive estuary.

Releasing approximately 37 million litres of effluent into the Diep River per day, Potsdam wastewater treatment works was given an 89% score in the Green Drop report, yet met minimum standards for effluent quality just 9% of the time during the year under review.

One of only six large estuaries on South Africa’s west coast, the Diep River estuary, also known as the Milnerton Lagoon, has become so polluted that schools of hardy mullet cannot survive its waters. Estuaries such as these are critically important as fish nurseries, says marine biologist and founder and director of Anchor Environmental Consultants, Dr Barry Clark.

They are breeding grounds for a large number of species which are important for inshore fisheries, which are a source of livelihood for small scale commercial and subsistence fishers, as well as recreational fishers who contribute to local economies.

“On the west coast there are only five or six reasonably large estuaries, and the Diep River is one of them,” said Clark, with their scarcity making them “disproportionately important to fisheries”.

With Potsdam wastewater treatment works releasing huge volumes of wastewater into the Diep River estuary, it is in an “extremely poor state of health at the moment”.

He said the quality of wastewater flowing into the estuary has “deteriorated severely” over the last decade.

“Diep River estuary is hugely important and it’s a tragedy it’s effectively lost to society,” said Clark.

The City of Cape Town is making efforts to upgrade Potsdam wastewater treatment works and rehabilitate the Diep River estuary, but is falling short of meeting a directive to do so meted out by the provincial Environmental Management Inspectorate in 2020.

Another of Cape Town’s high scoring contender wastewater treatment works is Athlone, which releases effluent into the Black River, a major river running through the central city area. Athlone wastewater treatment works scored just 15% on average for microbiological compliance across 2020 and 2021 – the period of the latest Green Drop audit. Its chemical compliance levels were at 54% for the period.

Chemicals of concern

Beyond the widespread failure of wastewater treatment across the country resulting in untreated or partially treated wastewater being released into the environment daily, even at treatment works that are awarded Green Drop certification awards and contender status, measuring the levels of pharmaceutical compounds and chemicals of emerging concern are not even mentioned in effluent quality standards.

Writing on South Africa’s largest news site, News24, Turton said the cocktail of chemical compounds in wastewater effluent, particularly pharmaceutical drugs such as the antibiotic sulfamethoxale found to be accumulating in marine organisms and fish, is creating drug-resistant pathogens.

“Think of this as a boot camp for microbes, because lazy and weak ones are destroyed by the low concentration of antibiotics, leaving only the stronger ones to flourish. In short, our boot camp for microbes is producing the next generation of multidrug-resistant pathogens,” stated Turton.

Petrik said while she was “happy” the Green Drop programme had been resuscitated as held the municipalities responsible for wastewater treatment responsible “in some form”, government needed to develop better quality guidelines.

When it came to the new contender status in the Green Drop report, she said it could not be considered a good outcome if they were able to be labelled as contenders for certification awards when they were “drastically falling short of effluent quality standards” which were in themselves insufficient.

“What are they basing their criteria on seems quite unscientific if they are not measuring environmental pollution? That needs to be improved,” said Petrik. “These chemicals of concern need to be dealt with.”

State of the waste water treatment works in Springbok, Northern Cape. Photo: Steve Kretzmann