As global population grows and industries expand, the stress on freshwater resources intensifies. Water management is a critical challenge with untreated or partially treated wastewater causing a negative impact on our ecosystems and human health. Focusing on this issue is no longer optional but a necessity for sustainable development.

We’re facing a growing number of environmental challenges, from polluted waterways to contaminated soil. While technological solutions are crucial, sometimes the most elegant answers come from nature itself. Algae is often overlooked as mere aquatic plants, but are in fact nature’s unsung heroes. These microscopic organisms have been purifying water bodies for millions of years, playing a vital role in maintaining ecosystems. Today, this natural process is being adapted and enhanced via scientific innovation to address modern wastewater challenges.

In this blog, we delve into the concept of phycoremediation and its applications in wastewater treatment.

WHAT IS PHYCOREMEDIATION?

The term phycoremediation is a combination of two words; phyco originates from the Greek word phykos which means “seaweed” or “algae”, while remediation is derived from the Latin word remedium, meaning “a cure” or “a remedy”. Phycoremediation therefore, means “remedying or curing using algae” (Phang, Chu, & Rabiei, 2023). The process involves leveraging algae’s natural ability to absorb nutrients, detoxify pollutants and degrade harmful substances present in the environment. 

Key mechanisms that drive its effectiveness:

• Nutrient uptake and assimilation:Algae needs nutrients like nitrogen and phosphorus, essential for their growth. Unfortunately, these nutrients are often overabundant in polluted environments, causing problems like algal blooms. Algae readily absorb these excess nutrients (nitrates, phosphates, ammonia) through their cell membranes and incorporate them into their biomass, reducing their concentration and preventing eutrophication (excessive nutrient enrichment) in water bodies (Mengel, Kirkby, Kosegarten, & Appel, 2023).  
• Heavy Metal Removal:Algae deals with heavy metals like lead, mercury, and cadmium in several ways (Machado, Valiaparampil, & Lavanya, 2024):
• Biosorption: Heavy metals bind to the surface of algal cells. The cell wall, made of complex sugars, proteins, and lipids, is particularly involved. We can think of this as the “sticky” approach.
• Bioaccumulation: Here, the algae actively take up the heavy metals into their cells, storing them in the cytoplasm or special compartments called vacuoles. They might use specialized transport proteins such as Phytochelatins or Cation Transporters to bring the metals inside.
• Bioprecipitation: Some algae can even trigger the heavy metals to form insoluble compounds, essentially locking them up and reducing their toxicity.
• Organic Pollutant Degradation: Pollutants are complex organic molecules. Algae produce enzymes – biological catalysts – that can break down these complex molecules into simpler, less harmful substances. Some algae can even use these pollutants as a food source!
• Carbon Dioxide Sequestration: Like all plants, algae are photosynthetic, meaning they use carbon dioxide to grow. In phycoremediation systems, this means they can pull carbon-dioxide from the atmosphere or even from industrial emissions, helping to mitigate climate change. The CO2 gets converted into algal biomass.
• Oxygen Production: A byproduct of photosynthesis is oxygen. In wastewater treatment, where oxygen is often depleted, this oxygen boost from algae is a lifesaver. It helps other beneficial microbes thrive and further break down pollutants (Ugwuanyi, Nwokediegwu, Dada, Majemite, & Obaigbena, 2024).

Two main types of algae that are used for phycoremediation:

• Microalgae: These are single-celled algae, like Chlorella and Spirulina. They’re like the workhorses of the operation, growing quickly and soaking up nutrients.
• Macroalgae: These are the larger, multicellular algae, like seaweed. They’re easier to harvest and are often used in coastal areas.

Case Study

Successful Implementation of Phycoremediation for Dairy Wastewater Treatment

Dairy industry generates large volumes of wastewater containing high levels of organic matter, nutrients, and suspended solids. Conventional treatment methods often struggle to meet stringent discharge norms, especially for nutrients. Researchers then explored phycoremediation as an alternative solution for the treatment. The microalga Chlorella vulgaris was used in open pond systems to assess its efficiency in pollutant removal. Raw dairy wastewater was pretreated, diluted, and introduced into the algal system under sunlight with proper aeration. Over a 16-day treatment period, significant reductions in pollutants were observed: 87% decrease in chemical oxygen demand (COD), 96% reduction in biological oxygen demand (BOD), and substantial removal of nitrates and phosphates. The process not only purified the wastewater but also generated valuable algal biomass, highlighting phycoremediation as a sustainable and efficient solution for nutrient-rich industrial effluents (Kumari, Kumar, Kothari, & Kumar, 2022).

Where Do We Use This Technology?

Wastewater Treatment: Algae removes nitrogen, phosphorus and other pollutants from wastewater, reducing COD and BOD. It is effective in industries like dairy, textiles, pharmaceuticals to treat heavy-metal-laden and nutrient-rich wastewater.

Carbon Sequestration: Algae utilizes Carbon dioxide during photosynthesis, making phycoremediation an effective method for capturing Co2 from industrial emissions and reducing greenhouse gases

Agricultural Runoff Treatment: Fertilizers and pesticides in agricultural runoff can pollute waterways. Phycoremediation offers a natural way to clean this runoff before it reaches rivers and lakes.

Aquaculture and Fisheries: Phycoremediation helps maintain water quality in aquaculture ponds by removing excess nutrients and preventing harmful algal blooms.

Oil spill Remediation: Certain algal species like Nannochloropsis degrade hydrocarbons, aiding in the cleanup of oil spills in marine environments.

Biofuel Production: Biomass generated during phycoremediation can be harvested and processed into biofuels, providing a renewable energy source.

Bioproducts: Algae are packed with essential macromolecules like proteins, lipids, carbohydrates, pigments. These can be extracted and used in various industries, from food and cosmetics to pharmaceuticals.

Conclusion

Phycoremediation stands at the intersection of innovation and sustainability, offering a natural, cost-effective, and eco-friendly solution to one of the most pressing environmental challenges—wastewater treatment. By harnessing the power of algae, this technology not only removes pollutants like nitrogen, phosphorus, and heavy metals but also contributes to carbon sequestration and the generation of valuable byproducts such as biofertilizers and biofuels. As industries and communities face increasing pressure to adopt sustainable practices, phycoremediation presents a promising path forward. It exemplifies how nature’s processes can be adapted to modern challenges, creating a cleaner environment and a healthier planet.

To learn more about how algae-based solutions can transform wastewater treatment, explore our ongoing projects and reach out to discover how we can help make your processes more sustainable.

Together, let’s work towards a greener tomorrow! https://agromorph.com/

About AgroMorph

AgroMorph Technosolutions focuses on creating environmentally conscious, economically viable solutions to urban environmental challenges. Initially specializing in algal ingredients, we have expanded to provide turnkey solutions leveraging advanced photobioreactor designs. Our scalable systems address diverse needs, from wastewater treatment to carbon sequestration, aligning with our vision of pioneering sustainable innovation to combat climate change.

References:

1. Phang, S.-M., Chu, W.-L., & Rabiei, R. (2023). Phycoremediation. In The Algae World (pp. 357–389). Springer. https://doi.org/10.1007/978-94-017-7321-8_13
2. Mengel, K., Kirkby, E. A., Kosegarten, H., & Appel, T. (2023). Nutrient Uptake and Assimilation. In Principles of Plant Nutrition (pp. 111–179). SpringerLink. https://doi.org/10.1007/978-94-010-1009-2_3
3. Avryl Anna Machado, Jithu George Valiaparampil, & Lavanya M. (2024). Unlocking the Potential of Algae for Heavy Metal Remediation2. Water, Air, & Soil Pollution, 235:629. https://doi.org/10.1007/s11270-024-07436-3
4. Ugwuanyi, E. D., Nwokediegwu, Z. Q. S., Dada, M. A., Majemite, M. T., & Obaigbena, A. (2024). The role of algae-based wastewater treatment systems: A comprehensive review. World Journal of Advanced Research and Reviews, 21(02), 937-949. https://doi.org/10.30574/wjarr.2024.21.2.0521
5. Sonika Kumari, Vinod Kumar, Richa Kothari, & Pankaj Kumar. (2022). Experimental and optimization studies on phycoremediation of dairy wastewater and biomass production efficiency of Chlorella vulgaris isolated from Ganga River, Haridwar, India. Environmental Science and Pollution Research, 29, 74643-74654. https://doi.org/10.1007/s11356-022-21069-1.