Municipal wastewater, commonly referred to as sewage, is a complex mixture primarily consisting of water, human waste, and household drain discharge. Despite the obvious health risks, sewage is not legally classified as “hazardous waste” under federal environmental law. This article explores the specific legal definitions that exempt sewage from this classification and details the genuine biological and chemical dangers that necessitate careful management.
How Regulatory Agencies Define Hazardous Waste
The primary federal law governing hazardous waste is the Resource Conservation and Recovery Act (RCRA). RCRA defines hazardous waste as a subset of “solid waste” that is specifically listed by the government or exhibits characteristics of ignitability, corrosivity, reactivity, or toxicity. Domestic sewage is generally excluded from the definition of solid waste under RCRA through the Domestic Sewage Exclusion (DSE).
This exclusion applies to untreated sanitary wastes and mixtures of domestic sewage and other wastes that pass through a sewer system to a Publicly Owned Treatment Works (POTW). Because municipal sewage is excluded from the definition of “solid waste,” it cannot be regulated as a hazardous waste under RCRA Subtitle C. Sewage is instead comprehensively regulated under the Clean Water Act (CWA).
The CWA focuses on regulating the discharge of pollutants into U.S. waters through the National Pollutant Discharge Elimination System (NPDES) permit program. RCRA regulates hazardous materials before they enter the environment, while the CWA regulates the quality of water discharged from treatment facilities. A chemical substance considered RCRA hazardous waste on land is treated as a regulated “wastewater” pollutant once it mixes with sewage and enters the sewer system.
The Actual Risks Present in Sewage
Despite the legal exclusion, sewage presents significant dangers to human health and the environment. These risks stem from a high concentration of infectious organisms and various chemical contaminants. The most immediate concern is the presence of biological pathogens shed in human feces, which are responsible for waterborne illnesses.
Raw sewage is a reservoir for numerous bacteria, including Escherichia coli (E. coli), Salmonella, and Shigella, which cause severe gastroenteritis and diarrheal diseases. Viruses such as Hepatitis A and Noroviruses are also frequently present, posing a risk of liver and acute gastrointestinal infections. Microscopic parasites like Giardia and Cryptosporidium are problematic because their protective outer shells make them highly resistant to standard disinfection methods.
Beyond the microbial threat, municipal sewage contains a complex mix of chemical hazards from domestic and industrial inputs. Residual pharmaceuticals, household cleaning products, and personal care products introduce trace toxic compounds into the wastewater stream. Industrial discharge may also contain heavy metals like lead or mercury, which present a long-term toxicological risk to environmental health and treatment facility workers. Exposure to these biological and chemical agents can occur through direct contact, ingestion, or inhalation of aerosolized particles.
Safety Measures for Handling Sewage Exposure
Accidental exposure to raw sewage requires immediate action to mitigate health risks. First, quickly evacuate the contaminated area and ensure proper ventilation by opening windows or doors, as sewage releases toxic gases and aerosols. If the spill source is controllable, turn off the main water line and electrical power to the affected area to prevent further contamination and electrical hazards.
For brief interaction with the contaminated area, personal protective equipment (PPE) is necessary. This includes waterproof gloves, rubber boots, and eye protection to prevent splashing into mucous membranes. After contact, hands and exposed skin must be thoroughly washed with soap and water; workers should also shower and change clothes immediately. Avoid touching the face, mouth, or eyes until hands are clean, as this is a common route for pathogen ingestion.
For large-scale spills or contamination involving porous materials like carpet and drywall, attempting cleanup without professional training is discouraged. Professionals have specialized equipment and disinfectants necessary to eliminate harmful pathogens and must be contacted to ensure complete property remediation. Individuals experiencing symptoms like fever, vomiting, or diarrhea following exposure should seek medical attention promptly.