“Devilfish” catfish, also called suckermouths, originated in South America but have spread to four other continents. These freshwater invaders compete with native species and eat their eggs, even damaging fisheries. But in Scientific reportsMexican researchers have shown that the parasites can be useful in unexpected ways: when pulped, they can help filter waste water from the ceramics industry.
The ceramic tile sector alone produces at least 16 billion square meters of product per year. Manufacturing facilities consume large amounts of potable water, and a biological cleaning system like this could allow reuse instead of letting the water drain.
Fish connective tissue collagen, when combined with an iron-rich salt, acts as a coagulant: the mixture destabilizes tiny bits of waste compounds so that they accumulate into larger globs that can be filtered out . Scientists found that this process removed 94% of solids from industrial ceramic wastewater and reduced an indicator of organic matter in the water by 79%. The researchers say their fish blend is less toxic than other available coagulants, a toxicity that discourages some manufacturers from filtering ceramic waste.
“Most of the time, the ceramic waste is left to dry in the sun and then the mud is disposed of or used as filler material,” says environmental scientist Miguel Mauricio Aguilera Flores of the National Polytechnic Institute of Mexico, who led the study. “People are wary of reusing water in any of their activities due to fears of toxicity resulting from chemical coagulants currently available, so right now the water resource is wasted.”
The mix is simple to prepare, but Aguilera Flores says getting enough biomass for industrial use could be a limiting factor. Trapping wild devils could meet modest demand, he says, but to thrive they may ultimately need to be farmed carefully.
“Managing effluent from any industry is a serious issue, and the ceramic manufacturing industry is no exception,” says Eileen De Guire, director of technical content and communications at the American Ceramic Society. “Taking advantage of an invasive species seems like a creative way to use one litter problem to solve another.”