Compiled by Tanya Olckers with technical input from Steve van Zyl, Technical Director, IOPSA
The United Nations Environment Programme stated in a 2019 report that more than 80% of the world’s wastewater, and 95% in least developed countries, is released into the environment without being treated. According to the report, 2.4 billion people on the planet do not have access to improved sanitation. The consequences of this are obvious, and alarming.
IOPSA’s Steve van Zyl inspects a tank Supplied by Steve van Zyl
United Nations South Africa has released these six goals to be achieved by 2030:
- Achieve universal and equitable access to safe and affordable drinking water for all.
- Achieve access to adequate and equitable access to sanitation and hygiene for all and end open defecation, paying special attention to the needs of women and girls and those in vulnerable situations.
- Improve water quality by reducing pollution, eliminating dumping and minimising the release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling safe reuse globally.
- Substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of fresh water to address water scarcity and substantially reduce the number of people suffering from water scarcity.
- Implement integrated water resources management at all levels, including through transboundary co-operation as appropriate.
- Protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, aquifers and lakes.
According to Nick Horne from EcoTanks, there seems to be an uptick in consumers looking for alternative solutions. “Rainwater storage tanks remain the most common products in our range,” he says, “Water pumps and filtration are catching up. Our domestic and commercial wastewater treatments system has also gained a tremendous amount of traction in South Africa.
He may well be onto something there as South Africa continues to watch its infrastructure crumble a day at a time. “We believe that becoming self-sustainable with energy provision, and with water backups and storage is the only long-term approach,” says Horne.
Septic tanks are defined by SANS 10252-2 as chambers that receive and retain sewage so that the waste material can be sufficiently decomposed. Septic tanks must discharge into French drains. French drains are absorption fields that are made up of a trench that is filled with material that is suitable to drainage and is used to get rid of liquid effluent from a septic tank.
A conservancy tank, as defined by SANS 10252-2, is a covered tank that receives and temporarily retains sewage, which needs to be emptied at regular intervals by honey suckers and disposed of properly by treatment plants.
With installations of either of these, the plumber needs to take serious note of the requirements laid out in SANS 10252-2. The installation of these tanks must be approved by a local authority prior to any work being done.
SANS 10400-P:2010 provides the requirements for conservancy tanks, septic tanks and French drains and any installation of any of these must comply with these requirements. SANS10252-2 provides further requirements.
A Calcamite unit. Supplied by Calcamite
Septic tanks
A septic tank, according to the definition in SANS 10252-2 receives sewerage and retains it. This waste is decomposed by bacteria. It is advisable not to put anything into the septic tank – such as soap water, chemics or foreign objects – that could potentially disturb the delicate balance of the micro-organisms’ eco-system.
Septic tanks provide a solution in areas where there are no municipal sewer line connections available, or possible.
| Benefits: An affordable solution to sewerage treatment with low maintenance potential. |
A KaacKai pod. Supplied by KaacKai.
Conservancy Tanks
Conservancy tanks store sewerage. When these tanks are full, waste is pumped out of these tanks by honey-suckers, sludge pumps or centrifugal pumps. This is then disposed of according to legislation, laid out in the South African Waste Act 59 of 200.
“A sustainable sewage system consists of so much more than just a tank,” says Bianca van Rooyen, marketing manager at Calcamite and JoJo, “Although the tank is of utmost importance and needs to be fit-for-purpose and safe to use for the intended application.”
Factors to consider when it comes to septic tanks include the sizing of the tank – it would need to remove about 40% of the wastewater’s organic load before it is released into the sub soil for further treatment. The soil at the location needs to be suitable for effluent absorption. Groundwater sources need to be taken into consideration to avoid pollution. The soakaway also needs to be the right size so that there is adequate seepage and absorption into the soil. Finally, environmental considerations also need to be made.
“A conservancy tank’s function is to temporarily collect and retain wastewater on the premises, ensuring that it does not contaminate groundwater,” says Van Rooyen. “Once the tank reaches its capacity, the wastewater must be pumped out and transported to an appropriate treatment plant. Alternatively, instead of disposal, the wastewater can undergo treatment in an on-site wastewater treatment plant for reuse in non-potable applications.”
| Benefits: A safe way to temporarily store sewerage, not much maintenance is needed, and it can be adapted to fit the needs of a variety of households |
Also included in the septic tank and conservancy tank bracket are tanks such as EcoTank’s Big Red wastewater treatment plant and those available from Calcamite. These units function as a conservancy or septic tank with a wastewater treatment unit included as an all-in-one convenient solution.
Propelair uses propelled air to assist in flushing. Supplied by Propelair
Plug-in Pods
Smart technologies, such as the wastewater recovery pods from KaacKai, can be used to generate high quality clean water that can be used for watering gardens, cleaning paved surfaces and irrigation or toilet flushing. The modular Pods come as a plug-in to conservancy tanks and contain patented Danish patented Bioblock cubes and biofilm that house microbes that assist in the breaking down of waste.
“Air blowers agitate and distribute oxygen, creating an ideal environment for microbial digestion of unwanted nutrients in the wastewater, with minimal use of power,” says Paige Albyn from KaacKai. “After treatment, water flows into the clarifier chamber, where bio-sludge is recycled back to the conservancy tank and water is disinfected using UV filtration. The result is high-quality, safe, chemical-free and environment friendly water ready for reuse for gardening, or for various purposes.”
The pods are highly efficient with a one-to-one water generation from wastewater, the smaller pods use the equivalent of a 40-Watt light bulb that stays on all the time.
“The smart wastewater recovery pods are not only about minimising damage to our environment, however crucial that is,” says Albyn. “They also save money. The average IRR for a medium sized pod for example is around 15%, depending to a large extent on the civils works.”
| Benefits: Modular, odour reduction, eco-friendly, easy to install and maintain, compact and efficient (1-1 ratio), and energy effective. |
There are toilet solutions available in order to support sustainable sewage disposal.
EcoTanks’ Big Red wastewater treatment plant. Supplied by Ecotanks
Propelled Air Toilets
Air propelled toilets from Propelair utilise an efficient technology that can lead to saving both water and energy. This comes with a claimed 84% reduction in water usage.
These toilets use only 1.5ℓ litres of water per flush. When compared to the SA average of 9ℓ per flush, it’s easy to see why it’s a water saver.
So how does a Propelair toilet work?
A two-section cistern provides one section for air and one for water. Before flushing, the lid is closed to form an airtight seal. The flush sensor is activated, and water goes into the pan to wash it and a blast of air from the pump follows. Because the lid is sealed, the air escapes and pushes out the pan contents.
The rest of the water fills the water trap. The flush takes 3 seconds, and the toilet is ready to be re-flushed in about half a minute.
These toilets can be fitted anywhere, falling in with whatever necessary design for the commercial washroom. It saves water, which is vital for a water scarce country like ours.
| Benefits: Water saving, reducing cost on the environment and the cost effective, reduces the spread of infection from virus and bacteria. |
Sanitech’s dry unit. Supplied by Sanitech
Non-waterborne systems
Pit latrines are still being used in South Africa. These could pose a danger to users if they are not well built or well maintained. They are often associated with bad odours, flies and could be regarded as unhygienic. Many South Africans make use of these latrines each day.
There are solutions available that are not only hygienic but are also easier on the environment. Sanitech’s Khusela unit is made for a water scarce country like South Africa and operates using far less water than regular toilets. The Khusela does not require any excavation for installation. Its rotating bowl effectively reduces odours, enhances cleanliness, and prevents the deposition of foreign objects into the pit.
The unit has a bladder that collects waste. The bladder is exceptionally durable and can be easily replaced. With a capacityof up to 2000ℓ, it effectively contains waste and prevents underground contamination.
It boasts a 3 to 5 year lifespan and can be effortlessly installed without disabling the unit.
Equipped with a tamper-proof safety hatch, only service teams can access it, ensuring that waste is securely sealed away from both users and service personnel, eliminating any risk of waste exposure.
SANS 30500 provides the relevant requirements for a non-sewer sanitation system.
| Benefits: reduced odour, hygienic, provides dignity to users, eco-friendly. |
As we navigate the uncertainty of the infrastructure around water, it is worth bearing in mind that even if the infrastructure does get back on its feet, there is a global need to implement water saving measures wherever possible. Raising awareness in communities and newly qualified professional plumbers on the benefits of sustainable sewage systems is just one step on a ladder to overall water conservation.
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