December 4, 2024

Flex Tech

Innovation in Every Curve

Repurposing Wastewater to Combat Global Water Scarcity

Repurposing Wastewater to Combat Global Water Scarcity

Water scarcity is a significant threat to global health, and it is expected to worsen in the coming years. Repurposing wastewater offers a new, valuable source of clean water, nutrients, and energy. This can be a game changer in addressing the global issue of water stress, yet the potential of wastewater is not yet fully exploited. EU-funded projects have tested innovative solutions to make the reuse of wastewater more feasible and efficient.

As little as 0.5% of the water on our planet is usable and available freshwater, and around 2 billion people do not have access to it. Water scarcity is exacerbated by climate change, leading to more frequent droughts, floods, and pollution. Coupled with a projected 55% increase in global water demand by 2050, this poses a significant threat to human health. 

The problem is also evident in Europe, where 17% of its population could face high to extreme water scarcity risks by 2050. In some southern regions of the continent, a large majority of the population already suffers from seasonal water stress in warmer months. Wastewater from homes, businesses, industries, and agriculture is a mix of chemicals, nutrients, and metals that can be treated and repurposed to help address water scarcity. In fact, about 320 billion cubic meters of wastewater are produced worldwide every year, over ten times the capacity of current global desalination. In Europe, for example, treated water reuse could be six times higher than the current levels. According to the EU’s Water Reuse Regulation, it is up to member states to decide if they want to allow water reuse in their territory or limit it only to certain areas.

“I believe one of the major issues worldwide right now is water scarcity, especially during the summer when the demand for fresh, drinkable water is even higher. Reusing wastewater can help relieve pressure on freshwater sources,” Kimberly Tumlos Solon, a postdoctoral researcher at Ghent University and part of the team of EU-funded project DARROW, told Earth.Org.

“Treating wastewater to a level suitable for its intended use, known as ’water fit for purpose,’ allows for its reuse for different uses such as irrigation, industrial processes, and even potable water. This approach can alleviate the strain on freshwater resources and is a sustainable way to manage water scarcity.”

AI Can Make Wastewater Treatment Plants More Efficient

Wastewater treatment plants produce a vast amount of data, such as water quality measurements, water conditions, and sediment levels. To better interpret these datasets the DARROW projects developing and testing artificial intelligence (AI) tools that guide operators to optimise wastewater treatment plant performance.

“We want to focus on reducing greenhouse gas emissions. We have tools that help track emissions and provide recommendations for minimising them. Another key focus is producing more biogas, which can be converted into heat and power to be used in the plant. This helps reduce the need for external energy,” Solon explained.

Analysing wastewater composition with AI tools can help the facilities run more independently and ultimately reduce energy and greenhouse gas emissions by 20% compared to traditional water treatment plants.

“We are using AI tools for three main purposes,” said Solon. 

“Firstly, we use AI to augment and clean missing data in order to detect anomalies in the system. Secondly, we adopt AI to control the process in the wastewater treatment plant. We believe this approach is more effective than traditional controllers, as it learns from history and from simulations to operate optimally. Finally, we have developed a decision support tool that provides recommendations on how to operate the plant more efficiently.” 

The developed AI tools will be tested at the wastewater treatment plant RWZI in Tilburg, one of the largest water recovery facilities in the southern Netherlands. It treats 10,000 cubic meters of wastewater daily, releasing clean water into the Zandleij River and supporting the region’s environmental sustainability.

“The Tilburg plant already has the basic equipment needed to build these AI tools. It was thus a perfect scenario to run the test,” said Solon. She explained that different tools are modular and flexible, meaning they can be adopted by other plants as well.

Algae and Microalgae Solutions for Circular Economy

Another problem that puts pressure on freshwater availability in Europe and the rest of the world is pollution. 

Agriculture is not only consuming a third of Europe’s water, but is also one of the major polluters and a major cause of water degradation in some regions across Europe. Nitrogen, phosphorus, and other nutrients are added to irrigation water to promote healthy plant growth and improve yields. However, not all nutrients are absorbed by the plants, and those in excess are washed into rivers and lakes. 

Earth.Org spoke with José Luis Guzmán Sánchez, professor of automatic control and system engineering at the University of Almería and part of the team of EU-funded project REALM. The project converts the nutrient-rich wastewater from greenhouses into valuable products using microalgae. 

“The microalgae absorb the nutrients and convert them into biomass, which can be utilised to produce bio-products such as bio-stimulants and biopesticides for agricultural purposes. This process not only purifies the water but also sustains the microalgae without requiring additional nutrients,” explained Sánchez. 

Using drain water from greenhouses to cultivate microalgae can prevent nutrient runoff, improve water quality, and conserve freshwater by removing excess nitrogen and phosphorus, which would otherwise harm aquatic ecosystems and the environment. REALM works with microalgae researchers, agricultural producers and technology experts across Europe to test this concept. 

They installed two fully operational pilot facilities in Wageningen, The Netherlands and Turku, Finland, and two industrial scale facilities are being installed in Faro, Portugal and Almería, Spain to understand how this system works specifically under the climatic and light conditions of Northern and Southern Europe. Thanks to solar energy, as well as new technology, the REALM team will automate the production of microalgae and help farmers recycle their drain water at no or reduced cost.

“Our communication architecture is designed with sensors installed everywhere to digitalise everything,” explained Guzmán. 

“We collect information and develop AI models to learn from the microalgae and reactor behaviour. We also develop optimal control that uses weather forecasts to predict the next 24 hours. The goal is to minimise the system’s inputs to save energy while maintaining optimal performance, which in this case involves cleaning water and producing biomass simultaneously.”

The system is expected to reduce the costs of growing microalgae by up to 50%. This could help microalgae producers reach more sectors and lower-priced markets, fully seizing the potential of microalgae for biofuels, sustainable food, feed, or medicine. When greenhouse farmers and microalgae producers adopt the REALM concept, they can help each other overcome challenges and sustainably increase their competitiveness.

“I believe there are several reasons to be optimistic about the development of the algae sector in Europe,” said Margarida Pinto Costa, Head of Research Department at NIVA and Project Coordinator of the EU-funded project LOCALITY.

“The diverse possibilities of algae applications offer a reduced market risk and increase the sector’s resilience. However, I think it is also fair to acknowledge that realising the full potential of this market will require continued innovation, investment, and research efforts. If we overcome these major hurdles, I believe that the algae sector can be a cornerstone for Europe’s sustainable economy.” 

The team of the project LOCALITY, which stands for “Leading Ocean’s Circular Algae Transition in the Baltic and the North Sea,” is exploring how to turn microalgae into sustainable feed and other products. The objective is to establish algae-based ecosystems by utilising waste from agriculture, fish, and textile industries in countries around the Baltic and North Seas. This approach will generate biomass for sustainable algae products, reducing costs by utilising nutrient-rich waste as a growth medium. 

Additionally, seaweed from the Baltic and North Seas will be used to help clean nutrient-polluted waters and provide materials for product development. 

To optimize algae growth, the team is also developing a real-time monitoring system that gathers sensor data to predict key growth parameters, enabling efficient, sustainable cultivation across the region.
The main challenge that all the aforementioned projects will face in relying on new technology, such as AI, to reach their goals is taking into consideration the energy usage that such machines require to function.

In fact, the energy consumption of AI, cryptocurrency, and data centres accounted for almost 2% of global energy demand in 2022. This is expected to double by 2026, reaching more than 1,000 TWh, which is roughly the same amount as Japan’s electricity consumption. Therefore, even if AI can definitely help in the development of innovative and sustainable solutions, it is important to also consider the energy cost that comes with it and what can be done to minimise the issue.

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