Biocide Usage When Cleaning Sewage Backups

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Biocide Usage When Cleaning Sewage Backups

Jason Yost • November 25, 2022

Should Biocides Be Avoided During Sewage Cleanups?

Someone wrote to me, asking about my previous blog on biocide usage on water damage and mold remediation projects. He, rightfully, points out that the conversation was focused on their use on mold. He, then, goes on to explain that he’s a water damage restoration technician, who gets called out to remediate sewage backups. He asks, “Should biocides be avoided during sewage clean ups too?” This is a great question.

Before I answer it, I want readers to know that I won’t be getting into a descriptive discourse on what biocides are. For that, I ask you to read my previous blog. I want to focus on this question asked as a follow up. That said, for the purpose of this blog, we are defining biocides as a product used to kill and liberate unwanted, sewage-based bacteria from the indoor environment, during the cleaning phase of remediation.

The short answer is no. But the use of these products requires knowledge of what one is dealing with (e.g., types of bacteria), the extent of damages, and the processes of removal prior to the application of products during the process of remediation. Allow me to explain.

The process of sewage remediation involves several things, including but not limited to the following:

The removal of sensitive building materials. These materials can include those that won’t hold up to the cleaning process. These can include those worn or compromised in ways that prevent cleaning without damaging them further or those materials sensitive to cleaning (e.g., drywall and insulation).
The removal of building materials obstructing the cleaning process. Often there are materials that obstruct the cleaning process (e.g., drywall that prevents access to the wall cavity where the backup took place). The only way to access the debris for removal is to remove the obstruction.
Extraction/physical removal of excess water. This is, often, achieved in two stages. The first is the extraction process where the technician utilizes an extraction machine to remove standing water. The second involves structural drying (e.g., negative air machines, dehumidifiers, and/or air moving/filtration devices).
Physical cleaning of surfaces within the work area. This involves processes whereby particulate debris is removed by HEPA vacuuming, steam cleaning, damp wiping, and/or other processes applicable to the removal of debris (visible and microscopic).

Obviously, if a trained professional is removing excess (i.e., standing) water and the materials containing high levels of unwanted bacteria, they’re quickly removing a large portion of the unwanted bacteria from the indoor environment. This has an immediate effect on the condition of the indoor environment, reducing the risk to occupants. This should be understood as the physical removal of an unwanted environmental stressor and the preferred method of remediating any indoor environment exposed to any environmental stressor. The problem with sewage backups is that one cannot extract all of the excess water from all of the building materials nor the bacteria associated with the backup, thus the cleaning and structural drying requirements.

That said, the use of biocides can’t be haphazard. They must be specific to (1) the organisms one is removing (2) the micro-climates applied (i.e., those services applied), (3) and its potential toxicity to the building occupants. (For more on the toxicity and limitations of biocides, read my previous blog.) For example, most sewage backups include organisms like Escherichia coli (E. coli), Enterococcus, Staphylococcus aureus, and Bacteroides. Products that have not been developed to kill these organisms won’t be applicable for your cleaning needs. Additionally, if you’re cleaning a surface with a sticky substance on it, the product should be such that it aids in the liberation of that substance. Products that don’t aid in that process aren’t applicable to the cleaning process.

So, based on this description of biocide use, it should be clear that the use of biocides is to (1) aid in the liberation and removal of unwanted, sewage-based bacteria from the surfaces being cleaned (2) and increase the bacterial decay (i.e., death) rates, so that, when the professional technician has completed their work, it is immediately safe for re-occupancy.

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