Milorganite is a brand of biosolids fertilizer produced by treating sewage sludge by the Milwaukee Metropolitan Sewerage District.

After settling, wastewater is treated with microbes to break down organic matter at the Jones Island Water Reclamation Facility in Milwaukee, Wisconsin.

[3][4] Rather than land filling solids left over from wastewater treatment, the sludge was used in a pioneering effort to make, distribute and sell fertilizer.

[7][8] Milorganite's roots began in 1911, when local socialist politicians were elected on a platform calling for construction of a wastewater treatment plant to protect against water borne pathogens.

[3][9] As raising taxes for public health was relatively controversial in the early 1900s,[citation needed] producing an organic fertilizer as a means of partially offsetting its operating cost was proposed.

With the help of researchers in the College of Agriculture at the University of Wisconsin, the use of waste solids in the form of activated sludge as a source of fertilizer had been developed in the early 20th century.

[10] Experiments showed that heat-dried activated sludge pellets "compared favorably with standard organic materials such as dried blood, tankage, fish scrap, and cottonseed meal".

[11] The Milwaukee Metropolitan Sewerage District's Jones Island Plant had the largest wastewater treatment capacity of any in the world when constructed in 1925.

[13][15][16] In 1926, Milorganite made its debut as the first pelletized fertilizer in the United States,[7] with sales directed at golf courses,[4] turf farms, and flower growers.

While working for Milorganite, he visited more than 80 percent of U.S. golf courses, to aid greenskeepers diagnose and cure "turf problems based on research-based knowledge".

[7] The sale of product does not generate sufficient funds to cover the costs of manufacture, but the Milwaukee Metropolitan Sewerage District states that the environmental benefits are a legitimate offsetting consideration:[5][1] In addition to the conflicting financial and environmental goals, it has to cope with fluctuations and vagaries of a changing waste stream.

[21] Milorganite can be used without restriction on gardens growing food crops intended for human consumption under United States Environmental Protection Agency (EPA) rules.

It complies with the EPA "Exceptional Quality" criteria, which establishes the strictest concentration limits in the fertilizer industry for heavy metals, allowing Milorganite to be used on food crops.

[25] Suggestions that Milorganite deters deer have been substantiated, but the reputed costs[A] of having it certified as a repellent are greater than its potential return.

[29][30][31] USEPA has set numeric limits for arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc.