Milorganite is the trademark of a biosolids fertilizer produced by the Milwaukee Metropolitan Sewerage District. The name Milorganite is a contraction of the phrase Milwaukee Organic Nitrogen, and was the result of a 1925 naming contest held in National Fertilizer Magazine. The biomass from activated sludge is heat dried to 95% solids and pelletizing at the Jones Island Water Reclamation Facility in Milwaukee, Wisconsin. Mistakenly, Milorganite 6-2-0 is referred to as a compost, which it is not. Compost are blends of thermophilic organic materials, with higher moisture, lower nitrogen and much higher application rates.
Raising taxes for public health was relatively controversial in the early 1900s. In 1911, reform minded Milwaukee Sewer Socialists were elected on a platform calling for construction of a wastewater treatment plant to protect against water borne pathogens.[1]
Experiments showed that heat dried activated sludge pellets "compared favorably with standard organic materials such as dried blood, tankage, fish scap, and cottonseed meal."[2] Sales to golf courses, turf farms and flower growers began in 1926.[3] Milorganite was popularized during the 1930s and 1940s before inorganic urea became available to homeowners after WWII.
Milorganite guarantees 4% iron. Iron is added to remove phosphorus from the wastewater before discharged to Lake Michigan. Heat dried biosolids contain slow release organic nitrogen, largely water insoluble phosphorus bound with iron and aluminum and high organic matter.[4] Given these characteristics, Milorganite is ideal for Low Input Lawn Care (LILac), a strategy to reduce the use of lawn care products while maintaining healthy turf grass.[5]
Milorganite 5-2-0 is sold throughout the United States, Canada, and the Caribbean as a home lawn and golf course fertilizer. Boston (Bay State), Ocean County New Jersey (Oceangro) and other sewerage authories pelletize heat dried biosolids "just like Milorganite" as part of wastewater treatment system improvements. Marketing to willing buyers is sustainable recycling of nutrients without the controversy that out-of-town agricultural use provokes.[6]
University research confirms anecdotal evidence that applying Milorganite on lawns and near plants deters deer due to its fecal odour. However, the manufactuer cannot tout Milorganite as a deer repellent because it is not registered as a "pesticide." Therefore, repelling hungry deer from Hostas remains an "off-label" use.[7][8][9][10]
Environmental regulations classify Milorganite as "exceptional quality" biosolids.