News Feature | November 13, 2014

Biosolids May Help Fight Global Warming

Sara Jerome

By Sara Jerome,

Biosolids may be a valuable tool in the fight against global warming.

"When biosolids are applied to land, some of the carbon remains in the soil, which keeps it out of the atmosphere. This process is called carbon sequestration, and it’s one way to mitigate some of the problems associated with climate change," according to the Seattle Daily Journal of Commerce.

In addition, biosolids can help improve plant health, which provides more greenery to take carbon from the atmosphere, according to the report.

If biosolids help clean up the atmosphere, then ratepayers in the Puget Sound region of Washington are fighting global warming just by flushing the toilet. The King County Wastewater Treatment Division uses sewage to make biosolids. The plant makes a fertilizer branded as ‘Loop.’

"King County's Loop biosolids are recycled as a fertilizer and soil conditioner in agriculture and forestry, and a portion of our biosolids is composted by a private company and sold as GroCo for use in landscaping and gardening," the county explained.

The utility is carbon conscious, recycling "100 percent of the 120,000 tons of biosolids it produces each year. Between biosolids recycling and the production of renewable energy, the utility estimates its carbon offset is equivalent to 42,000 tons of CO2, which is like taking 8,000 cars off the road each year," the report said.

Years ago, King County asked the University of Washington to take stock of its carbon use, including biosolids, in a study.

"The results from this process were encouraging. It seems as though appropriate management of a biosolids program is one way that a municipality can accrue carbon credits and reduce the impact that their operations have on the environment," according to BioCycle.