Hazard Alert – Biological Hazards in Sewage and Wastewater Treatment Plants

Those of us who work in the onsite wastewater industry must remain aware of the potential exposure to biohazards present in wastewater.  This isn’t so much a concern in the installation of a new system, however remediation or repair of an existing system provides the potential for contamination.

The Center for Construction Research and Training has published the following information for those of us working in the onsite wastewater industry.  The following article describes the biological hazards in sewage and wastewater, the diseases and symptoms that could result from exposure and ways to protect yourself.

During construction and maintenance of sewage and wastewater plants, workers may be killed by drowning, trench collapses, falls, confined spaces, and exposure to chlorine or hydrogen sulfide gas. The work can also make you sick.

Sewage and wastewater contain bacteria, funguses, parasites, and viruses that can cause intestinal, lung, and other infections. If equipment, work practices, and personal protective equipment (PPE) don\’t protect you from swallowing these agents, you can get sick.

During any part of treatment, transport, or application of sewage sludge, you can be exposed to materials that can cause disease. This is true even if you work around treated (class B) biosolids. Careful work habits can help protect you.

Some Biological Hazards That May Be in Sewage Or Wastewater
Bacteria may cause diarrhea, fever, cramps, and sometimes vomiting, headache, weakness, or loss of appetite. These are some bacteria and diseases they cause:: E-coli,shigellosistyphoid feversalmonella, and cholera.


  • Aspergillusand other funguses often grow in compost. These can lead to allergic symptoms (such as runny nose) and sometimes can lead to lung infection or make asthma worse. If you have other health problems, you may be more likely to get sick from aspergillus.



  • Cryptosporidiumand giardia lamblia may cause diarrhea and stomach cramps, and even nausea or a slight fever.
    • Roundworm (ascariasis). Most people have no symptoms. With a lot of roundworms, you may cough and have trouble breathing or you may have pain in your belly and blocked intestines.



  • Hepatitis Acauses liver disease. You may feel tired, pain in your belly, nauseous off and on; you may have jaundice (yellow skin) or diarrhea or not be hungry. The CDC says sewage workers are not at more risk of hepatitis A infection than other workers (see #1, below). If a lot of people in the community have hepatitis A, your risk may be higher than usual.


Bloodborne virusesare a hazard mainly to workers in health care facilities. Hepatitis B and HIV are bloodborne:

  • Hepatitis Bcauses liver disease. You may feel tired, have jaundice (yellow skin), pain in your belly, feel nauseous off and on, throw up, or not be hungry. The disease has not been linked to exposure to sewage in the U.S. (2)
    • Human immunodeficiency virus (HIV) causes AIDS. There are no known cases of wastewater workers getting HIV from their jobs in the U.S. and the risk is virtually nonexistent (2,3).

Protecting the Worker 

For work around sewage or wastewater, engineering controls and work practices are the best ways to protect workers from exposures to disease. When engineering controls are not possible, use personal protective equipment (PPE). For some jobs and around some hazards, respiratory protection is required.

Those working in the onsite wastewater industry (particularly maintenance and repair) should have access to:

  • Training and education about the hazards of wastewater and sewage
  • A place onsite with clean water for washing your hands
  • A place to wash and clean up after work
  • The right PPE, such as gloves, goggles, a face shield, water-resistant suit, or respirator – depending on the job
  • Clean areas set aside for eating and smoking
  • Cleaning facilities or services for clothing and equipment. (If clothing is badly soiled, change out of it. Keep equipment clean to limit your exposures to the disease-causing agents.)


What you can do:

  • Most important: Wash your hands well with clean water and soap before you eat or smoke and after work..
  • Do not touch your nose, mouth, eyes, or ears with your hands, unless you have just washed. Most of the time, people get these diseases when they have germs on their hands and they touch their mouth or nose or eyes.
  • Keep your fingernails short; use a stiff soapy brush to clean under your nails.
  • Wear waterproof gloves when you clean pumps or screens and when you handle wastewater, sludge, or grit.
  • Always wear gloves when your hands are chapped or burned or you have a rash or a cut.
  • Shower and change out of your work clothes before you leave work.
  • Do not keep your soiled work clothes with your other clothes.
  • Report any injury or illness you think you got from work right away.
  • If you do get sick, be sure to tell your doctor you work in a sewage or wastewater treatment plant or that you install or maintain onsite wastewater systems.
    That information will help the doctor know what to look for.

You need up-to-date shots for tetanus and diphtheria. If you want to know about shots to prevent hepatitis A, ask a nurse or doctor (4).

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