As it has for the past 40 years, King County produces Loop from solids extracted during the wastewater treatment process. Using Loop as a soil amendment closes the nutrient loop wherein harvested plants take nutrients from soil, humans obtain nutrients from the plants, and then we return nutrients to soil with Loop. Loop is an endlessly renewable resource restoring carbon and nutrients to the land for the good of plants, people, and Puget Sound.
Loop delivers a full suite of macro- and micronutrients, making it a superior source of plant food over synthetic fertilizers. It has a proven ability to improve soil structure thereby reducing runoff and erosion. Held to rigorous standards by both the EPA and the State of Washington, Loop is safe. Choosing to use Loop as a soil amendment reduces greenhouse gas emissions into the atmosphere. It has enriched Pacific Northwest landscapes as an ingredient in the commercial product GroCo since 1976.