“Devilfish” catfish, also called suckermouths, are native to South America but have spread to four other continents. These freshwater invaders can outcompete native species and eat their eggs, causing havoc in fisheries. But in Scientific Reports, researchers in Mexico showed the pests could be unexpectedly useful: when ground into a paste, they can help filter ceramics industry wastewater.
The ceramic tile sector alone produces at least 16 billion square meters of product a year. A biological cleaning system such as this could allow for reuse of potable water in manufacturing facilities.
Collagen from the fish’s connective tissues, when combined with an iron-rich salt, works as a coagulant: the mix destabilizes tiny bits of waste compounds so they amass into bigger globs that can be strained out. The scientists found this process removed 94 percent of solids from industrial ceramics wastewater, and it reduced an indicator of organic materials in the water by 79 percent. Researchers claim that their fish mixture is less toxic than other coagulants, which discourages some ceramic waste manufacturers from filtering it.
“Most ceramic waste is left to dry in sunlight, and then the mud is disposed of, or used as fill material,” said Miguel Mauricio Aguilera Flores, an environmental scientist at the National Polytechnic Institute of Mexico. He was the one who conducted the study. “People are afraid of the toxicity of chemical coagulants and don’t trust reusing water for any purpose.
Although the mixture is easy to prepare, Aguilera Flores warns that getting enough biomass for industrial use may be a problem. He says that while wild devilfish can be trapped, it could only support a modest demand. However, to grow the population, they may need to be farmed more carefully.
“Effluent Management from any industry is a serious problem, and the ceramic industry is no exception,” states Eileen De Guire (technical content and communications director at American Ceramic Society). “Taking advantage of an invasive species seems to be a creative way to use one waste problem to solve another.”