Biosolids

Terminology

Biosolids may be defined as organic wastewater solids that can be reused after suitable sewage sludge treatment processes leading to sludge stabilization such as anaerobic digestion and composting.

Alternatively, the biosolids definition may be restricted by local regulations to wastewater solids only after those solids have completed a specified treatment sequence and/or have concentrations of pathogens and toxic chemicals below specified levels.

The United States Environmental Protection Agency (USEPA) defines the two terms - sewage sludge and biosolids - in the Code of Federal Regulations (CFR), Title 40, Part 503 as follows: sewage sludge refers to the solids separated during the treatment of municipal wastewater (including domestic septage), while biosolids refers to treated sewage sludge that meets the USEPA pollutant and pathogen requirements for land application and surface disposal. A similar definition has been used internationally.

Quantities

Approximately 7,100,000 dry tons of biosolids were generated in 2004 at approximately 16,500 municipal wastewater treatment facilities in the United States.

In the United States, as of 2013 about 55% of sewage solids are turned into fertilizer, despite demand from farmers who wish to buy more. Challenges to increased levels of recycling include capital needed to build digesters, the complexity of complying with health regulations, and avoiding neighbors who object to unpleasant smells. There are also new forms of contaminants in urban sewage systems which make the process of producing high quality biosolids more complex. These have led some municipalities to ban biosolids on farms and even in forests.

Nutrients

Encouraging agricultural use of biosolids is intended to prevent filling landfills with nutrient-rich organic materials from the treatment of domestic sewage that might be recycled and applied as fertilizer to improve and maintain productive soils and stimulate plant growth. Biosolids may contain macronutrients nitrogen, phosphorus, potassium and sulphur with micronutrients copper, zinc, calcium, magnesium, iron, boron, molybdenum and manganese.

Industrial and man-made contaminants

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 the biosolid product 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.

Pathogens

In the United States the USEPA mandates certain treatment processes designed to significantly decrease levels of certain so-called indicator organisms, in biosolids. These include, "...operational standards for fecal coliforms, Salmonella sp. bacteria, enteric viruses, and viable helminth ova."

However, the US-based Water Environment Research Foundation has shown that some pathogens do survive sewage sludge treatment.

USEPA has also classified other pathogens that can appear in biosolids such as various protozoa, bacteria, viruses, and prions as "pathogens of emerging concern". Prions are unstoppable in the sterile confines of an operating room, not to mention a wastewater treatment plant. The pathogen spreads through the bodily fluids and cell tissue of its victims. The blood, saliva, mucus, milk, urine and feces of victims are infectious. Wastewater treatment doesn’t touch prions. In fact, these facilities are now helping incubate and distribute prions via released biosolids. Once unleashed on the environment, prions remain infectious. They migrate, mutate and multiply as they infect crops, water supplies and more. Prion disease impacts most, if not all mammals. Prion disease includes Alzheimer's disease, Parkinson's disease, Creutzfeldt-Jakob disease, mad cow disease and chronic wasting disease among members of he deer family. Prion disease also has been found in many other mammals, including sea mammals. These diseases are surging around the world and infectious prions found in sewage sludge (biosolids) is likely contributing to the epidemic. Prions shed from humans are the most deadly. They demand more respect than radiation. They’re being ignored by regulators and industry alike. As such, food and water sources are being contaminated with the deadliest forms of prions. When the U.S. government enacted the Bioterrorism Preparedness and Response Act of 2002, it classified prions as select agents that pose an extreme risk to food, water and much more. TSE surveillance is important for public health and food safety because TSEs have the potential of crossing from animals to humans, as seen with the spread of mad cow disease. TSEs also have the potential of being transmitted from humans to animals. The most common example is chronic wasting disease among deer species. Deer, elk, moose, reindeer and many other animals are being exposed to infectious waste in biosolids.

EPA regulations allow only biosolids with no detectable pathogens to be widely applied; those with remaining pathogens are restricted in use. Unfortunately, prions isn't on the list of pathogens that it regulates. The risk assessments are outdated, since prions were not recognized by science until the 1990s. The EPA's infamous sludge rule was crafted several years earlier.

United States

In the United States Code of Federal Regulations (CFR), Title 40, Part 503 governs the management of biosolids. Within that federal regulation biosolids are generally classified differently depending upon the quantity of pollutants they contain and the level of treatment they have been subjected to (the latter of which determines both the level of vector attraction reduction and the level of pathogen reduction). These factors also affect how they may be disseminated (bulk or bagged) and the level of monitoring oversight which, in turn determines where and in what quantity they may be applied.

History

As public concern arose about disposal in the United States of increasing volumes of solids being removed from sewage during sewage treatment mandated by the Clean Water Act, the Water Environment Federation (WEF) sought a new name to distinguish the clean, agriculturally viable product generated by modern wastewater treatment from earlier forms of sewage sludge widely remembered for causing offensive or dangerous conditions. Of three-hundred suggestions, biosolids was attributed to Dr. Bruce Logan of the University of Arizona, and recognized by WEF in 1991.

Microbiologist and EPA whistleblower, David. L. Lewis, has documented illness, death and livestock destruction traced to the use of biosolids. He also charges that the National Academy of Sciences, EPA, USDA, and other vested interests have expunged documentation and studies from reports in order to protect the EPA policy of using biosolids. Furthermore, Dr. Lewis charges that the emphasis on using biosolids in low-income urban and rural settings especially in the early years of "sludge magic" is an Environmental Injustice and human experimentation without informed consent.

Examples