气候变化领域集成服务门户

In 2013, a client asked Igor to find a building-wide sewage recycling system for their space in the Bay Area. He couldn’t find a single model on the market. Some months later, at a tech conference, Igor watched someone sterilize dog poop by whipping it in a food processor with potassium permanganate. He knew the chemical from his childhood: Called margantsovka, it was a common disinfectant. When his aquarium fish would start getting sick, he would add a few drops, he recalls. “The bacteria would die, and the fish would swim in a rosy water for a little while because potassium permanganate is also a colorant.” The compound (chemical formula KMnO4) causes an oxidizing reaction that kills microorganisms, including the pathogenic ones that commonly afflict humans. “It’s been widely used to wash wounds or disinfect a glass that someone drank from,” says Govind Rao, professor of biochemical engineering at the University of Maryland, Baltimore County. “It’s a very powerful oxidant, but it works best when pathogen loads are low.” Disinfecting typical sewage would require tons of KMnO4, but the Tartakovskys found a workaround—just do it at the source. Most people don’t carry large amounts of dangerous pathogens in their intestines (otherwise they’d be very sick), so what they flush isn’t usually festering with germs. It is after sludge floats through the miles of pipes for days that it becomes colonized with all sorts of bugs that naturally dwell there, growing and multiplying. “When sewage swirls down the pipes for days and weeks, its pathogen load is huge,” Aaron explains. “But if you get it right after someone flushed the toilet, the pathogen load is much lower.”