Published: October 8, 2015
By Katie Herzog
D.C., the American city most full of shit, is now powered by it.
The Washington Post reports that utility D.C. Water recently started using a Norwegian thermal hydrolysis system to turn sewage into clean energy. From the Post:
“Here’s how it works: When you flush or send soapsuds down the drain, the contents travel through miles of pipe and ultimately reach [the Blue Plains Advanced Wastewater Treatment Plant], off Interstate 295 in Southwest Washington. There, what looks like brown, murky water flows through screens that remove debris and then sits to allow solids to settle. Then, enormous centrifuges spin off the water and concentrate the remaining solids. (Don’t think too long about that part.)
The liquid is sent off to be treated and then returned to the Potomac River, and the concentrated sludge is pumped into large steel Cambi reactors, named for the Norwegian manufacturer. The reactors function like pressure cookers, using 338-degree steam and pressure to cook the sludge. Then it gets pumped to another tank. …
The sludge is then sent into one of four “digesters” — concrete cylinder tanks as tall as eight-story buildings — that each hold 3.8 million gallons. There, it spends about three weeks as microbial bugs nibble at it. The bugs convert the organic matter into methane gas, which is cleaned and sent to a nearby building, where turbines burn the methane gas and produce electricity. The entire system covers about five acres.”
It seems gross — and probably smells like a porta-potty at a NASCAR rally in August — but the Post reports that the system will produce enough electricity to power about 10,500 homes. Plus, there’s the savings. D.C. Water says the system will save $13 million annually, and it will eventually be able to sell the byproducts as compost. This might be the least shitty thing to come out of D.C. since, well, ever.