The specialist bioremediation company Blueplanet has been appointed by Magalies Water to assist in the remediation efforts of Hartbeespoort Dam.
Utilising Moleaer Nanobubble technology as a foundational tool in the multifaceted remedial programme, the company’s approach aims to restore healthy biology to the ecosystem.
“We are up to the task of remediating one of the most notable and hypertrophic (nutrient-dense) bodies of water in the country to restore its intrinsic values and biochemical processes,” said Heiner Dominick of Blueplanet. “Nanobubble technology is a transformative technology used to efficiently dissolve much-needed oxygen into the aquatic ecosystem. Lack of oxygen due to intense biomass growth causes mass fish kills and diminished biological nutrient processing. A healthy body of water has sufficient oxygen, microbial life and oxidation potential to deal with a certain amount of nutrient loading. These factors have been lost in over 70% of South Africa’s water bodies due to excess loading, most often from non-compliant wastewater discharge.”
He said biomass in the case of the Hartbeespoort dam is twofold. Firstly there is floating biomass in the form of Hyacinth, which blocks out beneficial ultraviolet light and atmospheric oxygen transfer. Secondly, suspended biomass, in the form of harmful algae blooms that flourish when hyacinth levels are reduced. In both these situations, the root cause is nutrient bulking (nitrate & phosphate), which is banked in the accumulated bottom sludge and flux back into the water column. Nutrients also arrive consistently from upstream due to sub-par wastewater treatment discharge. “Moleaer Nanobubble generators are unique in the fact that they provide oxygen transfer with high efficiency and at any depth. The true challenges are found at depth where accumulated sludge and decomposing plant matter reduce oxygen levels and release compounded nutrients such as nitrate and phosphate. By providing dissolved oxygen throughout the water column, an ideal environment is restored for aquatic lifeforms and the growth of beneficial microbes that deal with the nutrients and outcompete pathogenic microbes such as E. coli. Each nanobubble is about 2500 times smaller than a grain of salt. This lack of buoyancy means the beneficial reactions and oxygen transfer can occur at the sediment layer, where naturally occurring microbes deal with nutrient cycling and organic digestion of accumulated sludge. The nanobubbles will soften the compacted sludge and solubilise it. The process also removes the nutrients that hyacinth flourish from.”
According to Dominick, with one large Nanobubble generator installed at Ifafi Aquatic Club and focused on the immediate bay and Swartspruit inlet, an immense amount of data is being gathered. This data is provisioned for the design of the end-state solution to restore good health to the Hartbeespoort dam. The project is a one-year pilot project.
Blueplanet was responsible for cleaning the Roodeplaat Dam in 2023 in time for the World Rowing Masters Regatta. “BluePlanet has deployed Nano Bubbler Technology at a number of Anglo American Platinum biodiversity offset areas to rehabilitate water bodies impacted by sewer ingress. Internationally many projects are underway, specifically the much publicised Lake Elsinore and Lake Arrowhead projects,” Dominick said.
Well-known water scientist Dr Anthony Turton said he supported the nanobubble project. “Think of a bubble of air as something with a membrane or skin around it. That skin separates the air from the water, but it also allows gas to be exchanged. The gas in question is oxygen. The smaller the bubble the easier the exchange of gas. The smaller the bubble the more there are so the bigger the exchange of gas. The biggest benefit is the exchange of gas, which means that the water becomes oxygenated, but it also allows bad gas like methane to be removed. The other good thing is that the masses of tiny bubbles rise to the surface, bringing up cold deep oxygen-depleted water where it is exposed to the sun and a bit of heat.”
Blueplanet expressed its gratitude to the Ifafi Aquatic Club for making the site available for the project. “We are really excited about the project and will keep the public updated on the progress.”