The world is becoming more and more environmentally aware, to the point that even how grey stone tiles are made are scrutinized. A research team from the University College London has taken note of this, developing algae-coated tiles that can be placed on walls, combined with a wastewater tank stored atop the building, funnelling water through the tiles to filter harmful contaminants.

Dubbed Indus, these tiles operate via bioremediation, a scientific process  wherein biological organisms assist in breaking down contaminants, allowing for the cleaning of water in a sustainable manner. This isn’t a new idea, actually, as we’ve been using this technique since the 40s to help with the cleanup of heavily contaminated sites, where microbes like algae, bacteria and fungi are used to eat plastic and oil spills.

The team designed these tiles with India in mind, where, according to a report from 2015, up to 80% of the surface water is polluted. They even went so far as to travel to India, in order to see how textile production and its dyes and other contaminants affect the water in the country, testing which species of algae would be most effective in dealing with contaminants. This specific algae species was then used by the team for their design, infused into a seaweed-based hydrogel, which acts as housing for the algae while they do their thing.

The Indus tiles were made in India’s ceramic capital, Khurja, who has produced thousands of ceramic tiles and how grey stone tiles, with the designers cooperating with locals in order to discover the best materials and techniques. For the small batch they made, the team noted that the cost of each individual tile sat between $5 to $7 for every square foot, though they note that this will likely go down when handled en masse.

Lecturer Brenda Parker, UCL Biochemical Engineering, says that, while the prototype was designed with an Indian context in mind, the concept is global, and only requires that Indus be made with different materials in order to make it work in different regions. The designers are also looking to build an entire system of tiles, each variation aimed at dealing with specific heavy metals, with hopes of installing into a building in order to test how viable the system would be.