Algal Turf Scrubber from Hydromentia pulses water to stimulate algal growth, creating an efficient environment for pollutant removal.


  • Reduced nutrient pollution
  • Reduced nutrient toxicity
  • Natural
  • Cost‑effective
  • Sustainable


  • Domestic and agricultural wastewater
  • Stormwater treatment
  • Lake restoration

UN Sustainable Development Goals Addressed

  • Goal 6: Clean Water & Sanitation

  • Goal 11: Sustainable Cities & Communities


  • Algae
  • Diatoms
  • Bacteria

The Challenge

Nutrient pollution is an incredibly challenging and costly environmental problem. It is caused by excess nitrogen and phosphorus in the air and water, often as a result of fertilizer runoff from crops. Nutrient pollution has impacted many streams, rivers, lakes, bays and coastal waters for the past several decades, resulting in serious environmental and human health issues, and impacting the economy.

Innovation Details

The Algal Turf Scrubber® system cleans pollutant-laden water by pulsing water down a sloped substrate to stimulate algal growth, similarly to coral reefs. The algae remove nutrient pollutants, including phosphorus and nitrogen, from the water. The algae also produce pure oxygen as a byproduct, which can be used aquatic organisms and also helps to breakdown other toxic chemicals, such as lead and mercury. The algal mat can then be harvested and processed into marketable commodities such as soil-enhancing compost or biofuel feedstock.

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Biomimicry Story

The use of algae to remove nutrient pollution is . However, the Algal Turf Scrubber also mimics coral reef wave action by pulsing water over the algae. Coral reefs have a dense, biodiverse turf of filamentous algae that cover roughly 40% of their surfaces. Many coral reefs rhythmically pulse water over the algae, which enhances water and nutrient mixing, stimulating algal growth. It also prevents refiltration of water by neighboring polyps and enhances the coral’s .