A filter of coconut shells, bamboo and sand can be used to purify wastewater, according to researchers at the Campinas State University School of Civil Engineering. The method they have developed is a low-cost sanitation alternative ideal for small-scale operations, they say. “The technique is simple: we pour the wastewater into a stainless steel reactor through a bamboo frame and the water is purified as it passes through a filter of coconut shells and sand. Its effectiveness in removing impurities is close to 70 percent,” project leader Luana Mattos told Tierramérica.

Another bonus is that the filtered water contains high concentrations of nitrates and other nutrients, making it ideal for fertilization. “The method can be implemented in communities in northeastern Brazil, where coconuts are abundant,” stressed Mattos. “The next step is testing on a large scale,” she added.