Bidvest Protea Coin converts sewage water to greywater

Bidvest Protea Coin has entered a new era by installing a sewage treatment system, which converts sewage water into greywater at its Gijima Training Academy. This is a significant stride towards sustainable resource management. Through this system, sewage water is transformed into water that can be used for irrigation, allowing Bidvest Protea Coin to address water scarcity and promote sustainability at the academy, while also using the water to maintain the academy sports grounds.

This is how the Gijima treatment process unfolds:

• Sewage water enters septic tanks, where solids separate from liquids over time. Lighter solids, such as soapsuds and oils, float to the top, forming a scum layer. The liquid waste (effluent) exits the tank and moves to the balancing chamber before being pumped into the aeration tanks.
• Within the septic tanks, bacterial action digests the heaviest solids that settle at the bottom.
• Modern septic tanks often feature two compartments, with baffles at the inlet pipe to slow incoming waste, minimising disturbance to settled sludge. Another baffle at the outlet retains solids or scum in the tank for further bacterial digestion.
• The pretreated sewage water is then pumped to the aeration tanks for a nitrification and de-nitrification process, facilitated by oxygen. Aerobic bacteria digest the nutrient-rich sewage water, while slow or controlled clarification effectively denitrifies the water.
• Finally, ozone is used in the contact tank to sterilise the water before it is sent to the irrigation holding tanks for distribution via irrigation systems.

By using treated sewage water for irrigation, the academy conserves freshwater and municipal potable resources and reduces its reliance on traditional irrigation methods. The elevated nitrate and phosphate levels in the treated greywater serve as natural fertilisers, supporting healthy grass growth on the sports grounds.

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