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World-first treatment technology set to tackle nutrient runoff in the Great Barrier Reef and beyond

Nutrient runoff has long been known to damage the health of freshwater and marine ecosystems, but an award-winning, world-first technology using the power of seaweed is set to dramatically shift the dial on protecting water environments, including the Great Barrier Reef.

Pacific Bio’s breakthrough wastewater treatment technology – RegenAqua – won the Conservation accolade at the 2022 Reef Champion Awards held in Cairns last December.

Scientifically developed over 10 years at James Cook University, RegenAqua’s bioremediation process uses native Australian seaweed and sunlight to naturally remove contaminants such as phosphorus and nitrogen from municipal wastewater treatment plants, onshore aquaculture farming, abattoirs and agricultural run-off.

Pacific Bio CEO Sam Bastounas said the award was recognition of the outstanding work RegenAqua are doing in rehabilitation and restoration projects to improve the environment and quality of water entering the Great Barrier Reef catchment.

And Australian of the Year and climate change scientist Professor Tim Flannery agrees, saying the technology is world-leading, and truly deserving of the recognition.

“After climate change, nutrient runoff is the greatest challenge facing vulnerable sections of the reef. By using algae to clean up polluted water, as well as generating a biostimulant that cuts fertiliser use, it attacks the problem cost effectively, and at source,” he said.

“It’s an absolute no-brainer sustainable solution that’s going to change the landscape of industries – for the better.”

The award follows Burdekin Shire Council’s recent announcement that they are proceeding with a 4.5-hectare RegenAqua tertiary treatment facility to further clean water from its Ayr-Brandon sewerage treatment plant.

RegenAqua’s successful macroalgal bioremediation pre-facility at the Burdekin Shire Council plant proved the technology to be a cost-effective, carbon neutral and sustainable solution for water quality improvement in the Great Barrier Reef catchment and, ultimately, Australia wide.

Since the inception of the Burdekin Shire Council’s project in March 2021, the facility has exceeded all expectations, delivering positive results with nutrient pollutant reductions to below global best-practice of 5mg/L Nitrogen and 1mg/L Phosphorus.

Burdekin Shire Council Mayor Lyn McLaughlin said the extensive research and development conducted alongside James Cook University and Pacific Bio has paid off and holds great promise for other regional councils seeking cost-effective and sustainable solutions to nutrient removal. 

“This project is the first of its kind and will revolutionise the treatment of wastewater for all smaller coastal councils: the facility is significantly cheaper to both construct and maintain than a traditional tertiary wastewater treatment plant,” she said.

How RegenAqua works

RegenAqua General Manager Kevin Patrick said the technology’s fundamental focus is to protect and restore natural aquatic environments in a way that is financially viable and sustainable.

“It’s about enhancing the quality of water that’s being discharged into the local waterways and marine environment. But we are also aiming to provide an accessible technology to councils, or any water service provider with a circular-economy ambition,” he said.

“Macroalgae species have an enormous propensity to uptake harmful nutrients. We utilise local Australian seaweed or macroalgae, using different species in different parts of the country. The species we use must be endemic to the region,” he said.

“We feed the wastewater stream into our raceways, the algae absorb the nutrients, uptakes heavy metals and significantly reduce bacteria counts. It grows via photosynthesis, so it also sequesters carbon dioxide as well.”

RegenAqua’s long, rectangular tertiary treatment ponds – or raceways – are designed to be space efficient, but also to optimise the uptake of nutrients through the water using wheel paddles.

“We need to be able to move the water past the algae. It’s physical contact that allows the seaweed to uptake nutrients. It can be very tricky to get a homogenous distribution of nutrients through the water, but our raceways keep the water circulating,” Patrick said.

“Our raceways are highly-controlled environments. We can change the speed of our paddle wheels, the exchange rate and the depth of the water column. So we have some levers to help us optimise the process as much as possible.

“But the energy consumption from the process is very light, all you need is enough power to move the paddle wheels. That’s it.”

Ensuring circularity

Patrick said the RegenAqua solution comprises two key processes – bioremediation of nutrients and pollutants, and the production of a biostimulant, which can be used within the agricultural industry. 

“Following the bioremediation process, we harvest the macroalgae and repurpose it for the agricultural industry. We convert it into a powerful biostimulant called PlantJuice for farmers,” he said.

“The biostimulant is a companion product for fertilisers that’s been proven to produce strong crops that are quicker to establish and more resilient to heat and drought. We have had some phenomenal feedback on the efficacy of this product. It also reduces farmers’ reliance on traditional fertilisers.

“Aside from all of those benefits, creating the biostimulant from the macroalgae enables us to deliver a compelling, world leading, circular economy technology. It’s a nature-based solution, at its core. It’s about leaning into the power of nature to provide that benefit to the surrounding environment.”

One of the most impressive aspects of the new technology is that it is exceedingly cost competitive, while also remaining carbon neutral, Patrick said.

“If we look at our competing technologies from a traditional engineering perspective, we are about a quarter of the capital cost and a fifth of the operational cost. This cost competitiveness is incredibly appealing to many clients,” he said.

“In addition, we are a carbon neutral solution that’s also chemical free. It ticks a lot of boxes.”

The only potential constraint is that the technology does require space for set up, Patrick said.

“It’s a bolt-on technology and our feedstock is secondary effluent from the treatment plant. We need sunlight and space, so we need to be selective in terms of where we pitch our technology,” he said.

“But when we look at our circularity and our cost competitiveness, it certainly resonates with councils with a bit of extra space around their facilities that are looking for innovative ways to reduce their environmental footprint.”

Patrick said the level of technical competency required to operate the technology is relatively low compared to traditional treatment technologies, which often have a lot of moving parts, and membranes that are complex to operate and expensive to service and replace.

“Algal growth is a proxy for bioremediation rates. The higher your algal growth, the higher your bioremediation rate is, too. The key challenge is to be able to maintain the macroalgal species in an optimal fashion – so long as we keep our algae healthy, it will keep doing its job for us,” he said.

While most of the research and development has focused on applying the technology within a tropical climate, Patrick said preliminary work done to assess efficacy in temperate climates has been very promising.

“With a pre-facility currently operating with Sydney Water, we are moving towards getting RegenAqua up and running all around Australia, too,” he said.