akua water filtration
AKUA is a home water filter for Mexico City, made from nopal cactus and tezontle lava rock. A research prototype developed during a 2021 SPACE10 residency, with TU Delft.
Mexico City is one of the planet's most absurd urban paradoxes — a dense, wet, and viciously thirsty city built on top of a network of lakes. The basin sits on unstable layers of clay and lava rock that prevent water from refilling the aquifers below. Replacing a managed system of levees, lakes, and canals built by the Aztecs, modern-day Mexico City lives with the contradiction: when it rains, it pours, then it floods. With all that water, people are still thirsty.
The project began at the city scale, then narrowed. The big infrastructure is being repaired by other people, slowly and expensively. Local filtration initiatives exist, but most rely on materials imported from Europe or China — replacing one globalized supply chain with another. The research turned instead to the surrounding bioregion. The answer was already on the flag.
nopal and tezontle
The flag of Mexico shows an eagle on a nopal cactus growing out of tezontle lava rock, rooted in water. It's the Aztec origin myth of Tenochtitlán, and it's also a working description of the local ecology. Nopal and tezontle grow together across the basin, and both turn out to filter water.
Nopal mucilage — the goo inside the cactus pad — acts as a flocculant. Heavy metals and contaminants in the water bind to the mucilage and congeal into clumps that can be removed. Research has shown nopal can clean contaminated water 300 times more efficiently than aluminum sulfate, the standard industrial filtration agent, which is energy- and chemical-intensive. Extracting the mucilage from the cactus is as simple as juicing or blending it.
Tezontle is the porous volcanic rock that's been used in Mexico City architecture for centuries. Its porosity makes it act as a sponge in the filter — as the nopal mucilage flocculates contaminants, the tezontle catches and holds them.
a filter for the home
AKUA is a household-scale biosand filter that uses both materials. The form draws on Aztec pyramids and the architecture of Luis Barragán — stacked stone geometries with the proportional weight of sacred objects. The whole piece can be made within Mexico City using locally sourced components.
The filter is part of the studio's broader research thread on water — capturing it, filtering it, moving it through architecture without industrial systems.