Roodeplaat Dam. Picture: Oupa Mokoena/African News Agency (ANA)
Roodeplaat Dam. Picture: Oupa Mokoena/African News Agency (ANA)

Key treatment clears toxic plant from Roodeplaat Dam

By Liam Ngobeni Time of article published Apr 30, 2020

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Pretoria - Despite last-minute budgetary constraints that reduced planned treatment by 50%, a massive reduction of a toxic bloom’s biomass has been achieved at polluted Roodeplaat Dam.

Eyal Harel, the chief executive and co-founder of BlueGreen Water Technologies Inc, said the treatment was designed as a local proof-of-concept to demonstrate the ability to dramatically reduce a toxic cyanobacterial bloom economically and within a short time.

“It was scheduled ahead of the School Champs 2020 Regatta, which was scheduled for March to improve the water quality.”

He said that despite the financial constraints, a total reduction of the bloom’s biomass by 99.9% was achieved after the treatment.

“The BlueGreen Water Technologies team is currently undergoing discussions with South Africa’s regulator to put in a proposal for a treatment programme that can be implemented nationwide.

“Once full funding is secured, BlueGreen intends to permanently reduce the bloom in Roodeplaat Dam below dangerous levels and to ensure these conditions remain so for the safety and benefit of its surrounding communities.”

Harel said Roodeplaat Dam had been subject to uninterrupted pollution for decades.

“Its waters are full of nutrients that encourage the excessive growth of cyanobacteria as well as hyacinth.

“Naturally, a first step would be to control these effluents from reaching the dam.

However, he said that as long as the dam continued to have a high nutrient-load, it was crucial that an early detection and fast intervention mechanism be put in place to remove and prevent blooms from occurring altogether.

“This is planned to be achieved through a strategic public-private partnership - a combined effort that will include satellite remote sensing, local skills development that would enable them to conduct in-situ sampling and monitoring, complemented with rapid local intervention teams that are ready to timely deploy a Lake GuardTM treatment where and when needed.”

Low cyanobacterial levels will, in turn, allow natural, non-toxic competitors to reoccupy the vacant ecological niche, according to Harel.

“The latter will rehabilitate the aquatic ecosystem, improve the overall distribution of nutrients in the water column and serve a natural role in suppressing cyanobacterial resurgence.”

He said these natural processes would contribute to the long-term health of the dam and would contribute to the longevity of the Lake Guard treatment.

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Pretoria News

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