You’re Probably Overusing Disinfectants and It’s Harming Your Septic System

Most people are unaware of the negative effect that the overuse of disinfectants has on septic systems; and, with the emergence of COVID-19, the use of disinfectants and the resulting damage to septic systems has risen noticeably. So, how might these disinfectants damage your septic system and how can you avoid them?

First of all, it’s important to discern the different products that may be impacting these septic systems:

  1. Sanitizing wipes
  2. Laundry sanitizers (all products that claim to kill 99.9% of bacteria)
  3. Ammonium quaternary compounds (quats) 

The main active ingredients in many of the above products are detergents and contain thickening and stabilizing agents, as well. Other ingredients likely include surfactants, hydrotropes (for concentrated formulations like powders), preservatives, fragrances, perfumes, and dyes. Surfactants are typically the cause of the foaming or suds observed when cleaning agents come in contact with water. Though typically harmless to surface or groundwater, when surfactants are subject to saturated conditions, there is a strong tendency for soil sorption, which leads to an accumulation of anionic surfactants. These anionic surfactants may inhibit the occurrence of hydrolysis due to their poor anaerobic degradability, slow hydrolysis often causing solids to accumulate in the septic tank. Excessive surfactants are often easy to see in aerobic treatment units due to the addition of air into the system. 

Due to this common problem, it is widely recommended that wastewater applied to soil has surfactant levels that do not exceed 1 mg/L. In order to prevent high levels of surfactants in your wastewater here’s some advice:

Avoid hidden sanitizers in agents that often advertise as “anti-bacterial” and contain any of the following active forms of quats:

  • Alkyl dimethyl benzyl ammonium chlorides (C12-16)
  • Alkyl dimethyl benzyl ammonium chloride (C14 60%, C16 30%, C12 5%, C18 5%)
  • Alkyl dimethyl ethylbenzyl ammonium chloride (C12-14)
  • Alkyl dimethyl ethylbenzyl ammonium chlorides (C12-18)
  • Ammonium chloride 
  • Benzalkonium chloride
  • Benzethonium chloride
  • Cetalkonium chloride
  • Cetylpyridinium chloride
  • Cetrimonium
  • Cetrimide
  • Didecyldimethylammonium chloride
  • Dioctyldimethylammonium chloride
  • Dofanium chloride
  • Domiphen bromide
  • Methylbenzethonium chloride
  • Tetraethylammonium bromide

Choose dish soaps that pertain to the following criteria:

  • Plant-based surfactants (or just plain soap)
  • 1,4-dioxane-free
  • Phlathate (synthetic fragrance)-free
  • Dye-free
  • Petrochemical-free
  • Glycol-free
  • Phosphate-free
  • Caustic-free

When doing laundry:

  • Only use liquid bleach or other sanitizing agents when absolutely necessary to minimize the negative effect on good bacteria in the septic system
  • Rather, choose the “sanitize” setting on your washing machine, which uses an extra hot temperature to kill 99.99% of bacteria common to clothes, towels, and sheets
  • If your washing machine does not have a “sanitize” setting, it is recommended you use the hottest temperature water available
  • However, both “sanitize” cycles and hot water are harsher on clothes and should only be used when necessary 

By following the above criteria, or simply minimizing the amount of disinfectants you use, it’s unlikely you will experience any of these problems with your septic system. If you have any present problems with your septic system or have any more questions, contact us here on our website or call (804) 581-0001!

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