Human Waste as a Climate Solution

In King County, treated human waste, also known as biosolids, plays an important part in the government’s efforts to combat global warming. “Every year we provide the equivalent of taking about 8,000 cars off the road,” said Cat Gowan, a biosolids project manager in the county’s wastewater treatment division.

King County is far from alone in sending its biosolids to farms; about 55% of all treated human waste in the U.S. is added to soils. But the Seattle-area program, which began in the 1970s, is one of the nation’s most ambitious.