In this time of COVID-19 – with flu season right around the corner and sometimes conflicting information making the rounds – it is a good idea to go over the basics of bacterial and viral infections. To begin with, what is the difference between bacteria and viruses?
Bacteria are relatively complex, single-celled creatures – many with a rigid wall and a thin, rubbery membrane surrounding fluid inside the cell. They can reproduce on their own. Fossilized records show that bacteria have existed for about 3.5 billion years and can survive in different environments, including extreme heat and cold, radioactive waste, and the human body. Most bacteria are harmless; and some actually help by digesting food, destroying disease-causing microbes, fighting cancer cells, and providing essential nutrients. Less than one percent of bacteria cause diseases in people.
Viruses are smaller than bacteria. All they have is a protein coat and a core of genetic material – either RNA or DNA. Unlike bacteria, viruses can’t survive without a host and can only reproduce by attaching themselves to cells. In most cases, they reprogram the cells to make new viruses until the cells burst and die. In other cases, they turn normal cells into malignant and cancerous ones. Also unlike bacteria, viruses do cause disease; and they’re quite specific about the cells they attack. For example, certain viruses attack cells in the liver, respiratory system, or blood. Some can also target bacteria.
How Infections Occur
Three things are necessary for an infection to occur: (1) a source (such as an infected person, contaminated surface, medical devices, construction dust, wet materials from water leaks, etc.); (2) a susceptible person (someone who is not vaccinated or otherwise immune); and (3) transmission (through touching, sprays and splashes, inhalation, sharps injuries, etc.).
Food-borne transmission (food poisoning) is a common way that people become infected. In ideal conditions (warm and moist), bacteria double their numbers every 20 minutes. So if the initial infection is started with 100 bacteria, in three hours that number would increase to 51,200 bacteria.
Wastewater Releases
A relatively unknown source of potential transmission is from wastewater sanitary sewer overflows (SSOs) – which may occur when ruptures in piping or blockages allow wastewater to be released to the environment. This wastewater may contain E.coli and other harmful bacteria, as well as high levels of ammonia and nitrogen. While releases to subsurface soil would generally not be considered a likely transmission source to humans, releases into houses and surface waters would create a higher potential for transmission.
Wastewater releases to homes typically occur when a downstream blockage in the main pipeline causes wastewater to back up the main pipeline. As the backup proceeds upstream, any laterals encountered would also be filled with wastewater. Eventually, the wastewater would enter the home (unless a back-flow prevention device is in place) – typically at the lowest point, such as a basement or lower bathroom. The wastewater could soak floors, rugs, and any furnishings in its way. Specialty contractors would need to be engaged to conduct the cleanup. And post-remediation sampling should then be conducted to ensure that no residual bacterial or hazardous materials remain. The wastewater system operator (typically a city or special district) may be liable for damages; however certain exclusions pertaining to this liability may offer relief to the system operator.
Wastewater releases to the environment usually occur due to the same reason as releases to houses: blockages in the system. Some of these can be man-made, such as an accumulation of “flushable” wipes or coagulated fats, oils and grease; others are naturally occurring, such as root intrusion into pipes. These releases may occur at manholes, where the release may flow to impact nearby surface waters; and at aerial pipelines crossing or near surface water bodies. Again, the system operator may be liable for the release, which can carry large emergency response costs. In addition, the possibility for Natural Resource Damage Assessments is possible (e.g., a fish kill occurs due to the wastewater release).
Preventative Measures
How can the risk of becoming infected be mitigated? In general, minimizing infection risk is addressed through proper hygiene practices – including:
- Cleaning and sanitizing surroundings on a regular basis
- Frequent hand washing or sanitizing
- Avoiding touching one’s eyes, nose and mouth
- Washing and bandaging all cuts and skin abrasions
- Avoiding contact with sick people and items that they have touched.
- Using good food-safety techniques
For wastewater and sewage release situations, additional practices are recommended to reduce potential exposure – including:
- Not entering wastewater or sewage contaminated areas without the use of proper personal protective equipment
- Avoiding direct contact with wastewater/sewage and wastewater/ sewage-contaminated materials, except during decontamination activities
- Disposing of porous materials that were contacted with wastewater/sewage
- Cleaning and sanitizing surroundings after a wastewater/sewage event
How HETI Can Help
Wastewater and sewage releases are common occurrences that can result in unwanted exposure to bacteria and viruses. HETI has the experience and technical expertise to assist with wastewater and sewage releases, remediation, and exposure prevention. Whether it’s assessing a facility for potential exposures, or developing a remediation plan to reduce the potential for occupant exposure, HETI is here to help.