This fact sheet has been prepared by the Department of Health and the Department of Energy, Mines, Industry Regulation and Safety to provide information and best practice guidance for organisations and workers handling human effluent (sewage), biosolids or recycled water.
There is a risk of pathogens being present in treated sewage, biosolids or recycled water even if the human effluent treated at wastewater treatment plants has been disinfected.
People who may be at risk of exposure include:
- Workers at sewage treatment plants
- Workers transporting septage from septic tanks to licenced facilities
- Operators of recycled water schemes
- Workers applying biosolids to land
- Workers and laboratory staff handling sewage or recycled water samples or biosolids or contaminated soil samples
- Plumbers, irrigators and other people involved in maintenance work for wastewater systems or recycled water
This guidance document provides both workers and employers with details on the more common hazards when handling human effluent and the best practice preventive measures required to manage risks.
Hazards in sewage
Sewage can contain:
- Biological hazards. Pathogens (disease causing organisms such as viruses, bacteria, protozoa or other microorganisms) are found in sewage. Most of the health effects in occupational exposures to sewage are attributed to the microbial hazards. There are four principal categories of microbial hazards found in raw sewage:
- Enteric (intestinal) microbial pathogens, such as rotavirus and Cryptosporidium that cause gastroenteritis if ingested;
- Opportunistic pathogens, such as Pseudomonas aeruginosa and Legionella pneumophila
- Microbial endotoxins that could be inhaled in the workplace and
- Parasites such as intestinal worms and Giardia duodenalis
- Chemical hazards. Sewage can be deficient in oxygen or contain flammable gases such as methane and toxic gases such as carbon monoxide and hydrogen sulfide. For example, flammable gases may be released during vehicle transport of human sewage due to agitation, presenting a risk of fire or explosion. Sewage may also contain harmful substances from trade waste or industrial and commercial facilities, such as certain solvents, organic chemicals and heavy metals.
These microbiological and chemical hazards can pose an occupational health and safety risk to workers if not managed in a safe manner. The two primary routes of exposure are skin contact or inhalation. Affected areas may include the nose, throat, respiratory tract, eyes and any part of the body directly contacted or splashed by sewage. Inadvertent ingestion through contaminated tools or hands is another route of exposure that can be reduced by good personal hygiene practices and adequate use of personal protective equipment.