Earth kids have been learning about sewage pollution. They have focused on one of the local streams which flows into False Bay: the Else River has suffered ongoing sewage pollution thanks to broken pipes, bursting sewers and lack of maintenance in the area.
This catchment is enjoyed by children and pets and is rich in wildlife such as caracal, otters, squirrels and raptors. Sewage is also pumped into the ocean at Glencairn and often the untreated sewage leaks from pipes directly into the wetland and ocean. This causes a huge impact on environmental and human health. There is an ongoing problem of sewage pouring from drains onto the railway line and at Glencairn train station.
What Exactly is Sewage?
Sewage is waste matter such as faeces or dirty water from homes and factories, which flows away through sewers.
According to the OxyMem website, the terms ‘wastewater’ and ‘sewage’ are regularly used interchangeably, however there are differences between both. In fact, ‘sewage’ is considered a subset of wastewater.
Although the term ‘sewage’ usually brings toilets to mind, it is used to describe all types of wastewater generated from domestic dwellings. There are two types of sewage: blackwater, or wastewater from toilets, and graywater, which is wastewater from all domestic sources except toilets. Blackwater and graywater have different characteristics, but both contain pollutants and disease-causing agents that require treatment.
Wastewater is mostly water by weight. Other materials make up only a small portion of wastewater, but can be present in large enough quantities to endanger public health and the environment. Because practically anything that can be flushed down a toilet, drain, or sewer can be found in wastewater, even domestic sewage contains many potential pollutants. The wastewater components that should be of most concern to homeowners and communities are those that have the potential to cause disease or detrimental environmental effects.
Many different types of organisms live in wastewater and some are essential contributors to treatment. A variety of bacteria work to break down certain organic pollutants in wastewater by consuming them. Through this process, organisms turn wastes into carbon dioxide and water.
Many disease-causing viruses, parasites, and bacteria also are present in wastewater and can enter from almost anywhere. Likely sources include hospitals, schools, farms, and food processing plants.
Large amounts of biodegradable materials are dangerous to receiving waters such as lakes, streams, and oceans, because organisms use dissolved oxygen in the water to break down the wastes. This can reduce or deplete the supply of oxygen in the water needed by aquatic life, resulting in fish kills, odors, and overall degradation of water quality. The amount of oxygen organisms needed to break down wastes in wastewater is referred to as the biochemical oxygen demand (BOD) and is one of the measurements used to assess overall wastewater strength.
Inorganic minerals, metals, and compounds, such as sodium, potassium, calcium, magnesium, copper, lead, nickel, and zinc are common in wastewater from both sewage and wastewater. They can originate from a variety of sources including industrial and commercial sources, stormwater, and inflow and infiltration from cracked pipes. Most inorganic substances are relatively stable, and cannot be broken down easily by organisms in wastewater.
Wastewater often contains large amounts of the nutrients nitrogen and phosphorus in the form of nitrate and phosphate, which promote plant growth. Organisms only require small amounts of nutrients in biological treatment, so there normally is an excess available in treated wastewater. In severe cases, excessive nutrients in receiving waters cause algae and other plants to grow quickly depleting oxygen in the water. Deprived of oxygen, fish and other aquatic life die, emitting foul odours.
The State of South Africa’s Rivers
South Africa’s Department of Water and Sanitation (DWS) recognised the dire state of the country’s rivers three years in the Integrated Water Quality Management (IWQM) Policies and Strategies for SA in 2016 and 2017. They pointed out that eutrophication was “one of the country’s pressing water-quality challenges, along with salinisation, acid mine drainage, urban pollution and sedimentation.”
Apparently eutrophication has become a catastrophe in South Africa. It is caused by huge and continual quantities of sewage pouring into rivers. Eutrophication causes an overgrowth of algae that harms water quality, reduces oxygen, produces toxins, impacts river and marine life and affects food and human health.
Rivers suffering eutrophication have never recovered as sewage causes cyanobacteria blooms of toxic blue-green algae which smothers the river and all life therein.
About 60% of the 824 wastewater treatment works (sewage plants) in the municipalities are dysfunctional. This means that together they discharge over 5-billion litres of sewage into South African our rivers daily. And the country uses this water for drinking!
“Simply put, the more human settlements, the more sewage waste is produced, sometimes exceeding the volumes that wastewater treatment works can handle. Agricultural and industrial activities also contribute nutrients into rivers,” CSIR senior researcher Dr Melusi Thwala says.
Sewage Issues in Cape Town
Meanwhile, in the Mother City, Groundup reported that raw sewage “spills” are polluting the ocean and its marine life in and around Cape Town. Some environmental activists claim that sewage has been discharged there for more than 30 years. The discharges have raised come under the spotlight. Is it a spill or a deliberate discharge?
Read here for more on this dramatic finding: https://www.thesouthafrican.com/news/raw-sewage-cape-town-ocean-photographs-and-details/
False Bay Sewage Pollution
And again, in a report released not long ago by the City of Cape Town, many beaches in False Bay are severely polluted. This affects swimmers, surfers, fishermen, leisure enthusiasts and, of course, ocean and beach wildlife.
Muizenberg, Fish Hoek, Monwabisi and Beta Beach are among 31 polluted sites along Cape Town’s 307 km of coastline, as revealed by the long-awaited coastal water quality report released by the City on 20 March.
Almost half (45%) of the 49 testing sites in False Bay failed the minimum water quality guidelines in 2019. The water quality at almost every site from Muizenberg to Strandfontein and from Monwabisi to Gordon’s Bay is rated “poor”. Most of these sites suffer from chronic pollution, failing the minimum guidelines every year since 2015.
The predominantly clockwise water circulation leads to pollutants being deposited in the middle of the bay and in the north-eastern corner, at Gordon’s Bay, as well as in sheltered places such as Simon’s Town, Fish Hoek and Muizenberg.
The 22 False Bay sites rated “poor” include Muizenberg station, where hundreds of surfers paddle out almost every day, and Fish Hoek, which is a popular family beach due to its calm waters.
A newspaper revealed last year that ” The province’s favourite fish – snoek and hottentot – caught along the False Bay coast have been found to be contaminated by pharmaceutical products such as antibiotics, painkillers, antiretrovirals, disinfectants and industrial chemicals.”
A study conducted by the UWC chemistry department has shown that fish caught by small-scale commercial fishers in Kalk Bay are also contaminated by pesticides, herbicides and industrial chemicals, among others. In their peer-reviewed paper, senior Professor Leslie Petrik at the UWC’s chemistry department and Cecilia Y Ojemaye tested for 15 different chemical compounds in the fish fillets, gills, livers and intestines.
Time to act for the Oceans! Some useful contacts: