For most of us, the thought of algae in our water conjures images of murky ponds, but what if I told you that a specific type of algae could enhance the taste and odour of your drinking water?

Meet spirulina, a blue-green algae and potential water purification hero. It is already used for cosmetics and foods, and can be cultivated on a large scale. As they grow, spirulina cells also sequester carbon dioxide, which means it is not only carbon neutral but has the potential to be carbon negative.

The issue

For consumers, the taste and odour (T&O) of drinking water are like a first impression. These sensory qualities are crucial for how much we enjoy our water, making them a critical factor in consumer acceptance.

Environmental problems such as climate change can promote the growth of T&O-causing microorganisms. Unfortunately, many existing methods for tackling unpleasant T&Os in water fall short.

These treatments are either inefficient, meaning they do not remove enough of the offending compounds, or simply too expensive. This is why finding a more effective and cost-friendly way to eliminate T&O from drinking water is a pressing need.

The science

The study was carried out on behalf of waterTOP - a European network of water experts. Its objective was to assess for the first time the effectiveness of spirulina-based carbon materials in removing geosmin (GSM) and 2-methylisoborneol (2-MIB) from water.

Two commonly occurring natural compounds, 2-MIB and Geosmin produce strong musty and earthy smells and impart unfavourable tastes in drinking water. According to researchers, their presence even at trace levels in the water is the main cause of consumer complaints in many parts of the world as it is assumed unsafe for drinking.

In addition, utilities must employ costly treatment methods to remove these compounds from the water, which increases customer bills.

The results

Based on the study's findings, spirulina-based materials are promising in drinking water treatment applications, as they do not harm human cells while being highly efficient at removing GSM and 2-MIB from water.

The main aim of waterTOP is to increase capabilities and capacities in Europe for solving water T&O, by creating the first European network of water experts, end-users and stakeholders.