Biochar Filter Media to Mitigate Arsenic- and Fluoride-Contaminated Drinking Water

"Well water for many communities on the Independence Aquifer of Central Mexico contains dangerously high levels of arsenic and fluoride’s toxic cocktail known to cause dental fluorosis in children and crippling skeletal fluorosis, developmental disabilities, skin lesions, organ failure and cancer among longer term consumers. This public health hazard is due to unsustainable over-extraction by commercial agriculture, which forces wells ever deeper into mineral laden substrates. Similar groundwater contamination challenges affect marginalized communities elsewhere in Latin America, North Africa, Bangladesh, India and China – an increasingly worrisome global public health challenge. Caminos de Agua, a non-profit based in San Miguel de Allende, Mexico, is developing low-cost biochar-based filter systems that effectively remove arsenic and fluoride from drinking water. We have proven the effectiveness of animal bone biochar as filtration media for fluoride, and wood biochar treated with iron oxide for arsenic. Both media are produced from waste biomass’ ones from butcher shops and scrap wood from carpentry shops and mills’ co-fired in kilns made from used steel drums. The wood is loaded into a typical 55-gal. TLUD, and the bone into a 30-gal. retort situated inside a 55-gal. combustion chamber located directly above the TLUD base unit. The biochar is milled and packed into column filters made from inexpensive plastic plumbing parts. Our goal is to develop and deploy an aggressively affordable world-class solution to this locally acute, globally distributed, public health hazard; one that may be adopted by communities worldwide that confront similar water quality challenges.