At a treatment plant inauguration a few weeks ago, Ministers Carlos Montes (Housing and Urban Development) and Álvaro Elizalde (Interior) announced a new public policy: promoting the reuse of water from sinks, washing machines, and showers in new building projects to conserve water resources.
The news was enthusiastically received by the Greywater Reuse Project (GWR) team, led by Usach, who view these provisions as a significant boost for scientific initiatives focused on water efficiency. While Law No. 21,075, published in 2018, had already approved such projects, the GWR Project researchers indicate that the enactment of new opportunities are opening up with Decrees No. 40 from the Ministry of Health and No. 10 from the Ministry of Housing and Urban Development (Minvu).
According to the Ministry of Housing and Urban Development's website, the new standard is mandatory for public buildings with a surface area of 5,000 m² or more, as well as for certain other building types such as hotels, shops, schools, and terminals, based on their occupancy load and location. It's worth noting that while optional for residential buildings, the government is actively promoting its adoption via pilot projects across various regions.
Dr. Julio Romero, Usach academic and GWR Project researcher, believes the regulation "is undoubtedly a step forward that, despite being in its early stages, facilitates the implementation of solutions for disseminating various gray water treatment and reuse alternatives in high-visibility projects."
"Because our project has been developing diverse alternatives for graywater treatment and reuse," he explains, "this regulatory change will allow us to disseminate a wide range of technologies. These extend from nature-based solutions, such as artificial or constructed wetlands, to advanced technologies like electrochemical treatment systems, membrane filtration and separation processes, and the sorption of emerging contaminants, among others."
The Brazilian Experience
Coming to an end this year, the GWR Project has focused on the treatment and reuse of graywater in homes, developing systems to be implemented in a single-family pilot house. However, as the team explains, this regulation now opens opportunities for scaling these solutions to larger buildings with diverse water usage.
Dr. Romero emphasizes, "This will certainly be the beginning of action. It's crucial not only to define treatment systems and technologies, but also to focus on water reuse to visualize the possibilities of using treated gray water and other unconventional water sources in multiple applications such as irrigation, toilet flushing, washing, and cooling systems. This will optimize water resource management. Tools like Artificial Intelligence will also play a key role, and we must not overlook community acceptability studies."
The GWR Project's collaboration with Professor Ricardo Franci, an academic at the Federal University of Espírito Santo in Brazil and technical director of Fluxo Engenharia Ambiental, proved instrumental in understanding specific cases of graywater treatment and reuse in large buildings. The Usach academic highlighted this experience, stating: "Visiting various types of facilities in Brazil, we witnessed firsthand the application of nature-based, biological, and physical graywater treatment systems in residential, corporate, and industrial buildings. This demonstrated that scaling and detailed design are feasible for each unique situation, that the concept is readily accepted by communities, and that it necessitates a shift in perspective from both organizations and individuals."
"Considering the possibilities of reusing treated water for irrigation or toilet flushing, among other applications," he states, "poses the significant challenge of adopting an integrated perspective on water use."
About the GWR Project
Proposing the reuse of domestic greywater (which makes up about 65% of household discharge), the Greywater Reuse project aims to irrigate green walls and roofs, among other applications. This initiative seeks to enhance water management while offering benefits like improved thermal and acoustic insulation for homes. Funding is provided by ANID's Anillo Project ATE220224.
To test the project's technology, a 60 m² pilot house was built in Corfo's CTEC Technology Park, located in Laguna Carén.
The scientific team is made up of seven researchers from the universities of Santiago (5), Andrés Bello (1), and Bío-Bío (1).
More information at www.proyectoaguasgrises.usach.cl