Milorganite is the bran name of an organic nitrogen fertilizer produced by the Milwaukee Metropolitan Sewerage District. Popularized in the United States during the 1940s and 1950s, it consists of processed sludge from the Milwaukee Metropolitan Sewerage District Jones Island Wastewater Treatment Plant in Milwaukee, Wisconsin. The fertilizer is made up of microbes that have digested nutrients from the sewage stream along with added iron, used to strip phosphorus from the waste water flowing into Lake Michigan.