Surprisingly, it doesn’t smell that bad.<\/p>\n
During a tour on a recent spring afternoon, King County analyst Jim Pitts navigated his way through a network of open-air scaffolds and underground tunnels at one of the county’s wastewater treatment plants in Renton. Despite processing up to 200 million gallons of sewage, runoff and gray water per day, the plant is surprisingly clean and free of offensive odors or waste — even as tons of sludge, garbage and human feces are efficiently processed on the 80-acre site.<\/p>\n
On top of cleaning water and returning it to Puget Sound through pipes thousands of feet from shore, the King County South Treatment Plant also produces a product called Loop. Loop is a concentrated and sanitized form of human waste that is used as a highly potent fertilizer for agriculture and forests. It also has the consistency of cake, an observation Pitts was quick to point out as he molded a handful of the treated brown fertilizer into something resembling an animal before dropping it back into a machine.<\/p>\n
While this process may seem gross, nearly all pathogens have been removed from the finished Loop, and it is safe to use for many commercial uses across the state, including a collection of farms in Eastern Washington. On top of this, Loop and the wastewater plant are playing a role in a process that is already needed if the planet is to avoid the worst effects of climate change.<\/p>\n
Loop is so rich in carbon, it offsets the carbon that’s expended to process the plant’s wastewater. Loop also returns carbon to farmland, allowing crops to grow larger and soak up more carbon.<\/p>\n
There are several ways to remove carbon dioxide (CO2) from the atmosphere, many of which are outlined<\/a> in a report from the Intergovernmental Panel on Climate Change. The report presents a case for keeping global temperatures from rising more than 1.5 degrees Celsius above pre-industrial levels — and if that fails, the need to keep the increase below 2 degrees.<\/p>\n Agriculture, water access and heat-related deaths will be lower at 1.5 degrees. Even still, in areas around the equator, hot days have the potential to be up to 3 degrees Celsius warmer than now with 1.5 degrees of total warming.<\/p>\n In order to stay at or under 1.5 degrees, the world would need to reach net zero emissions by 2050, and for limiting warming below 2 degrees, net zero would need to be met by 2070.<\/p>\n This will require stopping the use of fossil fuels, but also removing carbon from the atmosphere, which will require large investments. James Mulligan is a senior associate with the World Resources Institute, which published<\/a> a post detailing several techniques to remove carbon from the atmosphere.<\/p>\n “It would be really great to have the technologies available by 2040,” Mulligan said.<\/p>\n Several of these options can be implemented fairly cheaply, but there is a trade-off between cost and effectiveness and feasibility. For example, reforesting is an option. Healthy forests are good at removing CO2 from the atmosphere and storing it in wood and soil. Every acre of restored forestland can rake in around 3 metric tons of CO2 annually.<\/p>\n