Biosolids: Making Use of Human and Industrial Wastes
King County in western Washington is home to Seattle, Bellevue and numerous smaller towns, and the 1.4 million citizens of King County generate 300 tons of treated sewer waste every day. Until the 1960s we dumped raw sewage into Lake Washington and Puget Sound. Today King County/Metro is committed to 100 percent capture and reuse of our sewage wastes. Federal law prohibits ocean dumping of treated sewage waste, landfilling is expensive, incineration is even more expensive and generates air pollution to boot, so Metro composts 10 percent of its biosolids and sells the rest as fertilizer.
Aside from culturally ingrained fear of human wastes, there are real considerations of disease and the potential concentration of industrial pollution in treated biosolids. The Cornell Waste Management Group has raised these and other technical concerns with the biosolids industry and government regulators. We spoke with Chuck Henry about King County's waste treatment system.