King County’s innovative program converts sewage into sustainable fertilizer

In King County, a pioneering project is turning sewage into a valuable resource, offering both environmental and agricultural benefits. For over four decades, the King County Loop Biosolids Program has been converting wastewater into ‘Loop’, a nutrient-rich organic fertilizer, enhancing both Marckworth Forest and farmlands in Eastern Washington.

This initiative, led by the King County Department of Natural Resources and Parks, stands out as one of the oldest biosolids programs in the United States. It repurposes wastewater treatment byproducts, thereby redefining forest management, agriculture, and environmental conservation strategies.

The process starts with sewage treatment, where organic waste is transformed in digester tanks using heat and microorganisms, similar to our digestive system. This method not only generates biogas for fuel and electricity but also returns essential nutrients to the land, improving soil quality and crop yields.

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Dr. Sally L. Brown from the University of Washington praises Loop for containing all the essential elements needed for plant life. The program’s environmentally friendly approach, favored over conventional fertilizers, reduces greenhouse gas emissions and conserves finite resources.

In Marckworth Forest, research has shown that applying Loop since 1973 significantly enhances tree growth, contributing to carbon storage and potentially lowering tax rates. The forest, managed by the Department of Natural Resources, also provides financial returns for the county through timber sales.

The program has demonstrated its positive environmental impact by storing carbon and reducing greenhouse gas emissions, effectively balancing emissions from transportation. Benjamin Axt, the project manager, emphasizes Loop’s role in promoting forest growth and productive agriculture.

Safety and efficacy are paramount, with rigorous monitoring and testing processes in place to ensure compliance with EPA regulations. The program also engages in proactive education and outreach to address concerns and misconceptions about the use of biosolids.

Looking to the future, the program aims to maximize the reuse of biosolids and diversify their applications, including a new compost project. This innovative approach presents a model for global communities, showcasing how waste can be transformed into a valuable resource for environmental sustainability and agricultural productivity.

Source: South Seattle Emerald