Rainwater harvesting should not be a luxury

Rainwater harvesting and management is nothing new. This technique has been used for thousands of years – from Mesopotamia to Ancient Rome, India and China. Today, growing water scarcity, climate change, rapid urbanisation and ‘Day Zero’ are making this ancient technology a viable option for cities.

Water scarcity is becoming one of the most critical risks threatening social and economic development throughout the world. Access to appropriate quality and quantities of water can either impede or enable economic growth. Rainwater harvesting can reduce water consumption, alleviate the damage caused by excessive amounts of stormwater run-off, and provide usable water. For cities and communities to become truly water-wise, adapting to use alternative water sources, such as rainwater, is key,” explains Chester Foster, GM, SBS Group.

Specialist manufacturer SBS Tanks, which is part of the SBS Group, provides rainwater harvesting solutions for the manufacturing, commercial property development, mining, agricultural, residential estate development, fixed fire protection, desalination and municipal sectors.

Due to their modular nature, SBS Tanks are easy to retrofit, requiring minimal site preparation and no heavy-duty machinery, and are made of steel that is hotdipped and coated with a molten alloy, Zincalume®. This, along with the internal water liner, makes SBS Tanks more resistant to corrosion, alleviating hidden maintenance costs. Systems designed by SBS can store from 7 000 to 4.4 million litres of water, and can maximise either vertical or horizontal space usage.

Considerations for different rainwater systems

“A rainwater harvesting system generally starts off with a catchment area, where water is brought from that area into a tank. A rainwater system off a building roof will usually include gutters and piping,” explains Foster. “First flush diverters will be required to help remove sediment and leaves that may have built up on a roof. If the harvested water is used as drinking water, additional processing will be required. SBS works with a network of experts to develop the perfect system for each site.”

The water tanks can be located above the ground or even inside a built structure. When the tanks are above the ground, rainwater should not have contact with sunlight, as this could lead to the growth of algae in the tank. Smooth surfaces on the inside of the tank, a potable water liner and a roof preventing sun exposure inhibit algal growth.

When designing a rainwater harvesting system, potential overflow needs to be considered. SBS Tanks can be fitted with water level control valves to regulate the water levels and various inlets, outlets, dump drains or scours. Excess water as a result of a heavy or continual downpour will typically be drained into additional water storage tanks, or diverted safely into stormwater systems; however, municipal bylaws always need to be considered. When designing a system, SBS engineers will work closely with a client’s engineers to ensure that all regulations are observed.

“Rainwater harvesting is highly sustainable and every building, public or private, should have a rainwater harvesting system. Water scarcity will always be with us, which means that current consumer and business behaviour will need to adapt to ensure sustainability of this precious resource. Every drop we can store, and reuse, will have a positive ripple effect,” concludes Foster.

SBS Tanks at the Buthelezi Museum

Due to their modular nature, SBS Tanks are easy to retrofit, requiring minimal site preparation and no heavyduty machinery Chester Foster, GM, SBS Group