Milorganite is a brand of biosolids fertilizer produced by treating sewage sludge by the Milwaukee Metropolitan Sewerage District. The term is a contraction (or portmanteau) of the term Milwaukee Organic Nitrogen. The sewer system of the District collects municipal sewage from the Milwaukee metropolitan area. The collected sewage is treated at the Jones Island sewage treatment plant (also called "Water Reclamation Facility") in Milwaukee, Wisconsin. As a side product, sewage sludge is produced. This sewage sludge is heat-dried to remove pathogens. The resulting treated sewage sludge (also called biosolids) is then marketed under the name of milorganite. The treated wastewater is discharged to Lake Michigan.
The recycled pelletized fertilizer is branded as milorganite and sold throughout North America. It can reduce the amount of manufactured fertilizer applied as it contains nitrogen and phosphorus which plants need for growth. The fertilizer is marketed throughout the United States and Canada, and in parts of the Caribbean.
After more than 90 years, the milorganite production and use is a long-term and large-scale example of a municipality-run nonprofit environmental program.
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History
The name Milorganite is the winning result in a 1925 naming contest held in National Fertilizer Magazine, a contraction of the term Milwaukee Organic Nitrogen. Its history began with Milwaukee's goal to clean up its rivers and Lake Michigan. Rather than land filling solids left over from waterwater treatment, the sludge was used in a pioneering effort to make, distribute and sell fertilizer. "Its production is among the largest recycling programs in the world."
The Jones Island Plant was the first sewage treatment plant in the United States to succeed in using the activated sludge treatment process to produce an organic fertilizer, and had the largest water treatment capacity of any plant in the world when constructed in 1925. The plant has been designated as a Historic Civil Engineering Landmark by the American Society of Civil Engineers.
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. As raising taxes for public health was relatively controversial in the early 1900s, producing 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. Experiments showed that heat-dried activated sludge pellets "compared favorably with standard organic materials such as dried blood, tankage, fish scap, and cottonseed meal." Milorganite made its debut in 1926 as the first pelletized fertilizer in the United States, with sales directed at golf courses, turf farms and flower growers. The brand was popularized during the 1930s and 1940s before inorganic urea became available to homeowners after WWII.
Since its inception, over four million metric tons of Milorganite have been sold. As of 2012, the plant produces about 45,000 tons of Milorganite per year. 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:
"Headquartered in Milwaukee, Wisconsin, Milorganite products are manufactured and marketed by the Milwaukee Metropolitan Sewerage District (MMSD), a regional government agency whose primary focus is providing water reclamation and flood management services for about 1.1 million customers in 28 communities in the Greater Milwaukee Area. Since 1926 MMSD has been a world leader in supplying Organic Nitrogen fertilizers for professional and residential use. While revenue generated through the sale of Milorganite products does not make up for the entire cost to produce and market, our belief in beneficial reuse and recycling makes producing our value added products the clear choice."
Even as it balances such conflicting goals and successfully navigates the fluctuations and vagaries of a changing waste stream,Milorganite has been at the forefront of the sewage sludge recycling industry in the U.S..
The process is the end point of the Milwaukee County sewerage system, which includes "three thousand miles of household laterals and another 3,000 miles of sanitary sewers." Also included is the 28.5 miles (45.9 km) "deep tunnel project" and the 521 million US gallons (1.97×106 m3; 434×106 imp gal) overflow storage system. Two plants, one on Jones Island and the other in Oak Creek, process sewage using bacteria. They employ about 220 people. Methane is recaptured and used to minimize energy costs.
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Product
Heat-dried biosolids contain slow release organic nitrogen, largely water-insoluble phosphorus bound with iron and aluminum and high organic matter.
Milorganite can be used without restriction on gardens intended for human consumption under USEPA rules. The product is tested daily for the presence of heavy metals and waterborne pathogens. It complies with the Environmental Protection Agency's (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. Milorganite is also tested for the presence of contaminants such as waste pharmaceuticals and other forms of drug pollution.
According to its Material safety data sheet Milorganite is "registered for sale in all 50 states and meets all federal and state requirements." The United States Department of Agriculture (USDA) certifies it as biobased because it is derived from 85% renewable materials. It is not, however, certified for use on U.S.D.A. organic farms.
Suggestions that Milorganite deters deer are unsubstantiated and the reputed costs of having it certified for such use are claimed to be prohibitive and the cost of certification is greater than its potential return.
Environmental concerns
The United States Environmental Protection Agency (USEPA) and others have shown that biosolids can contain measurable levels of synthetic organic compounds, radionuclides and heavy metals. USEPA has set numeric limits for arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc but has not regulated dioxin levels.
Contaminants from pharmaceuticals and personal care products and some steroids and hormones may also be present in biosolids. Substantial levels of persistent, bioaccumulative and toxic (PBT) polybrominated diphenyl ethers were detected in biosolids in 2001.
This finding came despite the EPA's previous assertion that all PBT organic pollutants of concern had been banned from production in the 1970s and hence these could be ignored in risk assessment. In 2007 toxic PCBs were detected in Milorganite, donated to the City of Milwaukee and subsequently applied on city parkland. The cost to the Milwaukee Metropolitan Sewerage District and tax payers was estimated as $4.7 million. The source of the PCBs was later determined to be a shuttered die-casting facility. The PCBs made their way to the treatment plant via sewer lines years after the facility stopped operation. PCBs were banned from commerce in the US in the mid-1970s. The United States Geological Survey analyzed in 2014 nine different consumer products containing biosolids as a main ingredient for 87 organic chemicals found in cleaners, personal care products, pharmaceuticals, and other products. These analysis detected 55 of the 87 organic chemicals measured in at least one of the nine biosolid samples, with as many as 45 chemicals found in a single sample.
Source of the article : Wikipedia
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