Sewage sludge

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WARNING! Sewage sludge is toxic. Food should not be grown in "biosolids." Join the Food Rights Network.

This article is part of the Food Rights Network, a project of the Center for Media and Democracy. Find out more here.

Sewage sludge is the growing and continuous mountain of hazardous waste produced daily by city sewage plants. The sewage sludge industry has created a PR euphemism it uses in place of the words 'sewage sludge': biosolids. There is now a SourceWatch Portal on Toxic Sludge The sewage sludge industry promotes its product through front groups and stakeholders including Water Environment Federation, US Composting Council, BioCycle magazine, and others.

What is Sewage Sludge?

A list of just some of the hazardous chemicals and pathogens found in sludge can be found in the article Sludge contaminants. Sludge contaminants include Dioxins and Furans, Flame Retardants, Metals, Organochlorine Pesticides, 1,2-Dibromo-3-Chloropropane (DBCP), Naphthalene, Triclosan, Nonylphenols, Phthalates, Nanosilver, and thousands more substances.

"Sewage is the mix of water and whatever wastes from domestic and industrial life are flushed into the sewer. To retrieve the precious water, the sewage is then 'treated,' that is, 'cleaned,' in what are called 'treatment plants.' The ideal of the treatment plant is to take out of the sewer water all the 'wastes' that sewering put into it. The water is 'cleaned' in the degree to which the pollutants which had turned the water into sewage are removed by treatment-primary, secondary, or tertiary-and concentrated in the sludge. We must note that, though the aim of sewage treatment is to produce clean water, it is never to produce 'clean' sludge. Indeed, the 'dirtier' the sludge - the more complete its concentration of the noxious wastes - the more the treatment has done its job. If there are industrial chemicals, pharmaceuticals, hormones, nano particles, prions, hospital wastes including antibiotic-resistant bacteria - and there will be all of these - you want them to end up in the sludge. Every waste produced in our society that can be got rid of down toilets and drains and that can also be got out of the sewage by a given treatment process will be in the sludge. Sludge is thus inevitably a noxious brew of vastly various and incompatible materials unpredictable in themselves and in the toxicity of their amalgamation, incalculably but certainly wildly dangerous to life." [1]

Why is Toxic Sewage Sludge Dumped on Farm and Gardens?

"The policy of disposing of sludge by spreading it on agricultural land - a policy given the benign term 'land application' - has its inception in the Ocean Dumping ban of 1987. Before 1992, when the law went into effect, the practice had been, after extracting the sludge from the wastewater, to load it on barges and dump it 12, and later 106 miles off shore into the ocean. But many people who cared about life in the ocean knew that, wherever it was dumped, the sludge was causing vast dead moon-scapes on the ocean floor. New EPA regulations for 'land application' were promulgated in 1993. With the aid of heating and pelletizing and some slippery name morphs along the way, EPA claimed sludge could be transmogrified into 'compost' ... . But the land “application” of sewage sludge ... will pollute the whole chain of life for which soil is the base." [2] In 2002, the National Research Council found that the "U.S. Environmental Protection Agency's standards that govern using treated sewage sludge on soil are based on outdated science."[3] This was again confirmed in 2011 when scientists found that noroviruses survive treatment that kills pathogens such as Salmonella.[4]

In March 2013, a study involving neighbors of land where sewage sludge had been dumped -- "living in rural and semi­rural areas within approximately one mile of sewage sludge land application sites in North Carolina, South Carolina and Virginia" -- found that "over half of respondents attributed physical symptoms to application events." More specifically, "Over half (18/34) of the interview respondents associated acute physical symptoms that lasted a short period of time with sludge application events near their home (Table 1). The most commonly reported symptoms were eye, nose, and throat irritations and gastrointestinal symptoms (nausea, vomiting, diarrhea). Other symptoms reported by more than one respondent include cough, difficulty breathing, sinus congestion or drainage, and skin infections or sores."[5]

Toxic Sewage Sludge Given Away as "Organic Biosolids Compost"

In 2009 a major controversy erupted in San Francisco when the Center for Food Safety and the Organic Consumers Association called on the SFPUC to end its give-away of toxic sewage sludge as free "organic biosolids compost" to gardeners. A March 4, 2010, demonstration at City Hall by the OCA forced a temporary halt to the program. (See articles below)[6] [7][8][9] [10] The misleading labeled "organic compost," which the PUC has given away free to gardeners since 2007, is composed of toxic sewage sludge from San Francisco and eight other counties. Very little toxicity testing has been done, but what little has been done is alarming. Just the sludge from San Francisco alone has tested positive for 1,2-Dibromo-3-Chloropropane (a.k.a. DBCP), Isopropyltoluene (a.k.a. p-cymene or p-isopropyltoluene), Dioxins and Furans. [11] The controversy spread to the famous Berkeley chef Alice Waters and her Chez Panisse Foundation. Waters and the Foundation advocate growing organic food and creating organic schoolyard gardens; toxic sewage sludge fertilizer is forbidden under the National Organic Standards Act in the production of commercial organic food. The executive director of the Water's Chez Pannise Foundation is Francesca Vietor, the vice-president of the SFPUC, the agency promoting and giving away toxic sewage sludge as "organic biosolids compost." Waters and her foundation have refused to publicly oppose the practice of growing food in toxic sludge.

EPA 2009 Toxic Sewage Sludge Survey

Targeted National Sewage Sludge Survey results are described in two EPA reports published in 2009. EPA found that dozens of hazardous materials , not regulated and not required to be tested for, have been documented in each and every one - ALL - of the sludge samples EPA took around the USA.[12] Hundreds of communities across the U.S. sell sludge products that are renamed biosolids and sold or given away as "organic fertlizer."

2008 Report from IATP

Environmental Working Group 1998 Reports on Toxic Sewage Sludge

Scientific Papers and Technical Reviews of Sewage Sludge

Dozens of peer reviewed scientific studies examine and confirm the many hazards of sewage sludge See: Scientific Studies of Sewage Sludge for a synopsis of leading studies and a PDF of each

What's in sewage sludge

A list of just some of the hazardous chemicals and pathogens found in sludge can be found in the article Sludge contaminants. Sludge contaminants include Dioxins and Furans, Flame Retardants, Metals, Organochlorine Pesticides, 1,2-Dibromo-3-Chloropropane (DBCP), Naphthalene, Triclosan, Nonylphenols, Phthalates, Nanosilver, and thousands more substances.

From the 1995 book, Toxic Sludge Is Good for You, with permission:

The HarperCollins Dictionary of Environmental Science defines sludge as a "viscous, semisolid mixture of bacteria- and virus-laden organic matter, toxic metals, synthetic organic chemicals, and settled solids removed from domestic and industrial waste water at a sewage treatment plant."

Over 60,000 toxic substances and chemical compounds can be found in sewage sludge, and scientists are developing 700 to 1,000 new chemicals per year. Stephen Lester of the Citizens Clearinghouse for Hazardous Wastes has compiled information from researchers at Cornell University and the American Society of Civil Engineers showing that sludge typically contains the following toxins:

In addition, a 1994 investigation by by the US General Accounting Office found that "the full extent of the radioactive contamination of sewage sludge, ash and related by-products nationwide is unknown." Most of the radioactive material is flushed down the drain by hospitals, businesses and decontamination laundries, a practice which has contaminated at least nine sewage treatment plants in the past decade.

In 1977, EPA Administrator Douglas Costle estimated that by 1990 treatment plants would be generating 10 million tons of sludge per year, a thought that "gives us all a massive environmental headache." In 1995 there were about 15,000 publicly-owned wastewater treatment works in the United States, discharging approximately 26 billion gallons per day of treated wastewater into lakes, streams and waterways. Before treatment, this wastewater contains over a million pounds of hazardous components. Sewage plants use heat, chemicals and bacterial treatments to detoxify 42 percent of these components through biodegradation. Another 25 percent escapes into the atmosphere, and 19 percent is discharged into lakes and streams. The remaining 14 percent--approximately 28 million pounds per year--winds up in sewage sludge.

Once created, this sludge must be disposed of somehow. Available methods include: incineration (which pollutes the air), dumping into landfills (which is expensive, and often leaches contaminants into groundwater), and ocean dumping (where it has created vast underwater dead seas). A fourth method --gasification, using sludge to generate methanol or energy--is described by EPA's Hugh Kaufman as the "most environmentally sound approach, but also the most expensive." A fifth approach --using sludge as plant fertilizer--was considered hazardous to health and the environment until the 1970s, but it has the advantage of being inexpensive. As budget concerns mounted in the late 1970s, the EPA began to pressure sewage plants to adopt the cheapest method available--spreading sludge on farm fields.

Other SourceWatch resources

PRWatch Articles

External Resources

External Articles 2008 - 2011

Articles below are arranged from oldest to newest:



  • Xoco Shinbrot, Beyond Pesticides, "Biosolids or Biohazards?, Pesticides and You, organizational quarterly magazine, Volume 32, Number 3, Fall 2012, pp. 9-15.






  1. About Sewage Sludge,, Accessed June 18, 2010.
  2. About Sewage Sludge,, Accessed June 18, 2010.
  3. Sewage Sludge Standards Need New Scientific Basis, National Research Council, July 2, 2002, Accessed June 22, 2011.
  4. Emily Gertz, Safety Rules For Sewage Sludge May Be Outdated, Chemical & Engineering News, June 15, 2011, Accessed June 22, 2011. Link broken, but part of article archived here.
  5. Amy Lowman, Mary Anne McDonald, Steve Wing, and Naeema Muhammad, "[ Land Application of Treated Sewage Sludge: Community Health and Environmental Justice," Environmental Health Perspectives, March 11, 2013 (online).
  6. Heather Knight, Nonprofit calls PUC's compost toxic sludge, San Francisco Chronicle, September 27, 2009.
  7. Barry Estabrook, Free Compost--Or Toxic Sludge?, The Atlantic, December 1, 2009
  8. Anna Werner, Concern Over SF Compost Made from Sewage Sludge, CBS Channel 5, March 3, 2010
  9. Leora Broydo Vestel, Food Groups Clash Over Compost Sludge, New York Times Green Inc. blog, April 9 2010.
  10. Chris Roberts, Farmers Call PUC's Shit, Will Dump it on City Hall Today, San Francisco Appeal, March 4, 2010.
  11. Jill Richardson, What San Francisco Found in Their Own Sludge, La Vida Locavore blog, April 8, 2010.
  12. TNSSS: EPA-822-R-08-016 and EPA-822-R-08-018. Published by EPA, January 2009.