Just last month, President Cyril Ramaphosa and Minister of Water and Sanitation Senzo Mchunu were in Pietermaritzburg to give addresses on upgrades to water supply in Vulindlela and to the Darvill Sewage Works.

The work on Darvill Sewage Works has been substantial, with the government reporting that over R1-billion has been spent on upgrades there over the last decade. The upgrades are aimed at handling predicted increases in demand for a minimum of 20 years. This is a major step in the right direction.

Effectively and efficiently treating wastewater before it is released into the environment is vital to ensure that our streams, rivers and dams (primary sources of freshwater) are not contaminated, leaving them safe and suitable for further use, often by vulnerable communities, for recreation, farming, and for supporting the ecosystems on which we all depend.

This kind of remediation of sewage works around the country is obviously sorely and urgently needed, as has been discussed in many articles, both scientific and otherwise, over the last two decades.

The shockingly poor state of South Africa’s sewage works was already apparent in the Green Drop Reports between 2008 and 2013, before the former minister Nomvula Mokonyane put a stop to the Green Drop Assessment process.

To the benefit of all South Africans and South Africa’s environment, Minister Mchunu commendably and courageously reinstated the Green Drop Assessments in 2021. However, in the interim without monitoring, the situation has deteriorated: the latest report shows that 39% of the 995 sewage works assessed were found to be in a critical state (i.e., considered dysfunctional) and that only 23 achieved the coveted Green Drop award for excellence.

Unfortunately, the reality behind the already worrying Green Drop headlines is worse than most people in South Africa realise.

Wastewater inflow, or lack thereof 

Treatment of sewage is one issue, but first wastewater must actually get to the treatment plant to be treated. The upgrades at Darvill were planned to enable the plant to cope with increasing wastewater flows as Pietermaritzburg grew and sewers were extended to previously unserved areas.

However, over the last 10 years, the wastewater inflow to Darvill has not increased — it has in fact decreased. The long-term data on treatment volumes indicate a seven million litre per day decrease in the amount of sewage treated at Darvill in 2021 compared to 2011.

President Cyril Ramaphosa at the Darvill Wastewater Treatment Plant, received by Minister of Water and Sanitation, Senzo Mchunu. (Photo: Elmond Jiyane/GCIS)

If the inflow trend prior to 2010 had been maintained, the flow should, in that time, have increased by 14 million litres per day. The implication is that more than 20 million litres of sewage is going missing from the sewer network every day.

Not surprisingly, the median level of Escherichia coli (E. coli, high levels are associated with untreated sewage) in Pietermaritzburg’s streams and rivers has increased 10-fold in the last 12 years. We can show any interested party the places where sewage has been openly and obviously spilling (and thus, not reaching sewage treatment works) for months and sometimes years.

These problems are repeatedly reported. In response the Department of Water and Sanitation (DWS) sends warnings, then directives, followed by the Department of Environmental Affairs (DEA) asking for turnaround plans. But the turnaround does not come.

Pietermaritzburg is not alone and is nowhere near the worst. For example, the Madadeni Sewage Works in KwaZulu-Natal was treating 77% less sewage per day in 2021 than it was in 2013. The Butterworth Sewage Works in the Eastern Cape and Meyerton Sewage Works in Gauteng were treating 75% and 67% less, respectively.

None of these three sewage works has changed their design capacity or the catchment they service in that time, so the amount of sewage they are treating should increase or remain stable, certainly not drastically decrease.

What’s possibly worse, is that out of the 876 public sewage works for which there are some Green Drop data in both 2013 and 2021, 431 do not have comparable inflow data. That is half of them. For half of our wastewater treatment works, the sewage inflows are not even measured consistently, so no one has any idea how the volume treated per day has changed over time.

This has consequences. For example, this year the organisers of the Dusi Canoe Marathon took the unprecedented step of moving the start of the Dusi canoe marathon to Bishopstowe in response to the chronically high and unsafe pollution levels in the Msunduzi River in Pietermaritzburg. It is quite possible the residents of Pietermaritzburg will never again enjoy the iconic spectacle of the Dusi paddlers shooting the Ernie Pearce Weir.

Read more in Daily Maverick: Anger grows over Durban’s apparent apathy in dealing with widespread river contamination

Durban’s sewage woes are another glaring example. Ethekwini blamed the April 2022 floods for the very high levels of E. coli in Blue Lagoon and the harbour, but the reality is that the problems predated the floods.

In the 2021 Green Drop assessment the volumes of wastewater treated by Durban’s Northern and Central Sewage Works were just 50% and 62% of their 2013 levels. This means that by 2021 a staggering 66 million litres of sewage per day, every day, was no longer reaching these two major sewage works compared to 2013 — almost the same as the bulk of Cape Town’s sewage production (Green Point outfall).

What goes “missing” in a year, the volume of raw sewage that should be reaching these two sewage works, but is not, could fill over 9,600 Olympic-sized swimming pools.

That sewage is still being generated, so where is it going? Straight into streams, rivers, dams, groundwater, and ultimately the ocean — untreated and unaccounted for. 

Durban’s beachfront has gone through extended closures to the public on grounds of severe risk to public health and safety, no doubt at huge cost to the tourism industry and Durban’s local and international reputation. This should have galvanised anyone and everyone responsible for Durban’s future prosperity into action.

Hammanskraal cholera crisis

The recent cholera outbreak in Hammanskraal has been well-covered in the news. Naturally, as the crisis has unfolded, attention has focussed on the Rooiwal Sewage Works, a strong contender for the source of the problem, perhaps with justification.

But a comparison of the 2013 and 2021 Green Drop data shows that the volume of wastewater treated by the Rooiwal Sewage Works in 2021 was 14 million litres per day less than it had been in 2013. That’s not a problem with the sewage works — it’s a problem with the management and state of the sewer infrastructure network that is supposed to supply the sewage works.

Read more in Daily Maverick: Killer cholera hits amid decade-long bickering over Hammanskraal water crisis – and tender scandals

Even if the Rooiwal Sewage Works was functioning perfectly, the streams and rivers in that area would still be inundated with 14 million litres of raw, untreated sewage every day — and that is a major human health disaster waiting to happen.

This problem is not necessarily reflected in the Green Drop scores. According to these, the Johannesburg North Sewage Works, by far the biggest sewage works in SA (treating over 420 megalitres per day in 2013), showed no change in its GD score (77%) from 2013 to 2021. The sewage plant appears to be working reasonably well on the sewage that arrives.

However, the volume treated dropped by nearly 78 million litres per day from 2013 to 2021. For context, that is equivalent to all of the sewage generated at either Stellenbosch, Polokwane, Mthatha or Amanzimtoti — an amount that is just not getting to the Northern Sewage Works.

So, the headlines about the disturbing finding of the most recent Green Drop report and failing sewage plants are overlooking a catastrophic failure hiding in plain sight, a sleeping (now stirring, considering Hammanskraal and Durban’s beaches) giant of human health and environmental hazard: far too much of our sewage is just not getting to the treatment plants.

Warning ignored

When the lights go off, everyone knows about it and there is huge pressure on our political leaders to do something about it. When the taps run dry, it’s a political and socioeconomic crisis.

But if a significant portion of our sewage does not get to the sewage works, if sewage spills go untended for months and years, who notices, and who cares? Then people start dying of cholera, and people ask, how could that happen in South Africa? Aren’t we world leaders in wastewater treatment technology?

While the public is left wondering how South Africa could be the epicentre of a cholera outbreak, experts are wondering how it didn’t happen sooner.

Already in 2009, Prof Etinosa Igbinosa and colleagues had raised the alarm: “Vibrio pathogens [the genus of bacteria containing those responsible for cholera] easily survive treatment processes… thus posing a potential health risk to the rural communities which depend on the watershed for domestic and recreational purposes. There is a need for intervention by the appropriate regulatory agencies to ensure compliance with wastewater treatment facilities for regulating effluent quality standards” (bracketed information added by us).

In 2010, M Dungeni and colleagues echoed the sentiment: “The presence of pathogenic E. coli, S. typhimurium, Vibrio cholerae and viral indicators in treated wastewater effluent [at sewage plants in Gauteng] is a potential public health hazard, as this water source is directly discharged in receiving water bodies and may be used by communities for multiple purposes. There is therefore a great need to adopt a new approach in wastewater treatment processes and to ensure the proper management of wastewater treatment plants in all the provinces, in order to produce effluents that comply with the current standards”.

These were followed by nearly a dozen other scientific articles showing similar issues and giving the same warnings.

It is also worth noting that while the loss of human life is tragic and garners the press and public attention, pathogen pollution is only a part of the problem in rivers.

Untreated or poorly treated sewage can cause extensive nutrient enrichment, which is the foundation for massive algal growth, particularly when it reaches our critical storage dams. The process is already happening, but in time our dams will be covered in toxic blue-green algal blooms.

This will drive up the cost and difficulty of treating water for drinking supply, and render the dams useless for recreation and dangerous for any other use. Farmers will find it difficult or even impossible to meet standards for exporting into valuable markets due to the poor quality of the water they have to use for irrigation.

The highly valuable tourist industries in our coastal towns and cities will wither away, as local and international tourists get the message that our beaches are no longer safe for bathing.

All of this is completely avoidable and not that expensive to remedy, relative to most of the problems government faces. It is, evidently, just not a priority at the moment. 

Managing sewers and sewerage systems is one of the easier human and environmental challenges we face — all it needs is to be given the priority it deserves.

The upgrades due at Rooiwal, and those now implemented at Darvill are encouraging. There is also a promising engagement with citizen science and conventional science from organisations such as Unicef, the Duzi-Umgeni Conservation Trust (Duct), as well as the DWS for community-based monitoring of these issues and to improve water resource monitoring and management.

We have made a start, but South Africa needs drastic action to attend to the state of its wastewater treatment infrastructure, including the too-easily-ignored problem of sewage not reaching treatment works.

It’s not glamorous, but it is fundamental to securing public health and environmental sustainability, which is one of the main justifications for the existence of government in the first place. We ignore it at our peril. DM

David Still is a professional civil engineer specialising in the field of water supply and sanitation. He is the founder and has been since 2006 the chairperson of the Duzi-uMngeni Conservation Trust (DUCT), which champions the environmental health of the uMsunduzi and uMngeni Rivers.

Dr Mark Graham is director of GroundTruth Environment and Engineering in Hilton, KwaZulu-Natal, a research associate at UKZN’s Centre for Water Resources Research, and a founder member of the United Nations University’s Regional Centre of Expertise. He has a long involvement with the Water Research Commission (WRC) as a research scientist.

Nicholas B Pattinson is a research scientist at the environmental research and consulting group GroundTruth. He has an MSc. Zoology and has authored several scientific papers, as well as nearing completion of his PhD Biological Sciences.