Many of us drive past our local wastewater plant on a semi-regular basis and likely think nothing of the processes that they are using to treat the water that flows through it. We continue with our day and never think twice about the downward impact that we, local businesses, and major corporations may have on the local wastewater treatment plant’s processes for identifying chemicals and avoiding dangerous, untreated water entry back to our waterways. But did you know that we actually play a larger role in this cycle? Did you know that you and your company are likely using products on a daily basis that could have significant, long-term impact to the overall ecological health of your community?
In this article we will review how the use of common products found in our homes and businesses, containing QACs, can impact our water sources and potentially cause havoc on our treatment plants if not properly identified and monitored through regular testing.
What are QACs and where are they found?
Quaternary Ammonium Compounds or “QACs” are a group of chemicals that are used widely in surfactants, disinfectants, cleaners, solvents and personal-care products. QACs have been used for decades as antistatic and softening agents, surfactants, antimicrobials, disinfectants, and preservatives. QACs appear in some of our most common household products, such as shampoo, detergents, disinfectant wipes, hand sanitizers, and many more such as:
- Disinfectant in sprays and surface wipes
- Antistatic agents in fabric softeners
- Antibacterial in sanitizers and hand soap
- Algaecide used in swimming pool products
- Preservatives in eye drops
It is important to note that when we use these products, we may be eliminating one concern while fueling another. While these chemicals can help us with everyday hygiene and health needs, they will eventually find their way into our domestic and industrial wastewater.
Why is it important to identify QACs?
Wastewater treatment plants, also commonly referred to as “WWTPs”, biodegrade organics including toxic and harmful chemicals as part of routine secondary treatment processes. Because QACs are sequestered by particulates, QACs tend to bioaccumulate in the WWTP, which can cause the QAC compounds to reach sufficiently high levels. At these high levels, these disinfectants will kill the aerobic microbes upon which wastewater secondary treatment depends. This then causes a nitrogen lockdown, which releases reduced forms of nitrogen into the WWTP. These reduced (rather than oxidized) nitrogen species are then discharged from the WWTP, depleting the receiving stream’s oxygen and ultimately facilitates algal bloom in the stream. Unfortunately, this means that QACs will not only be found in wastewater, but also in surface water and the sediment of receiving streams. Even when WWTP concentrations have not yet reached toxic levels, studies have found that QACs are still prevalent and often not entirely removed from the wastewater prior to discharge from the WWTP.
Due to increasing QAC concentration, the WWTP’s process will eventually fail, resulting in untreated wastewater being discharged. Human exposure to raw or partially treated sewage can cause numerous diseases, including diarrhea, hepatitis, and even typhoid fever. Moreover, algal blooms, encouraged by the presence of sewage in streams, can lead to change in biodiversity and eventually impact the functioning of an entire ecosystem. This becomes a major cause for concern not just for our environment but also for the local population, as exposure can lead to significant health risks as described above.
Additional impacts of QAC’s on the Environment and Human Health
When QACs are discharged from WWTPs into our natural water sources they become associated with river and creek sediment over time. The expected time for QAC degradation to occur is insufficient to rid the environment of this hazard, allowing for the continual exposure of microbial QACs, which in turn may encourage or even facilitate antibiotic resistance. As our own resistance to antibiotics increases and the effectiveness of disinfecting practices decreases, and subsequently the use of QACs are increased as we try to remedy these issues.
How could ignoring QACs and not testing for them hurt us long term?
This matters to all of us because of our reliance upon the continued efficacy of disinfectants found in our everyday household cleaning and health products. Globally, the rate at which products that contain QACs are used has significantly increased and it is anticipated to be sustained. An influx of QACs over time could contribute to changes in microbial communities which, in turn, could potentially harbor antibiotic resistances. Based on these increased usage trends, we can conclude that the amount of QACs released into the environment will also rise, risking WWTP failure, which might cause not only widespread illness but also biodiversity loss.
Testing for QACs & how SPL can help.
When a WWTP’s QAC concentration reaches a toxic level, the plant will no longer be able to properly treat incoming wastewater. This inevitably results both in costly non-compliant discharges and potentially catastrophic ecological damage. Fortunately, this cycle can be prevented through routine testing for QACs. While some WWTPs test their plants on a yearly basis, we are excited to see that many are testing for QACs on a quarterly basis. Cities and municipalities with pretreatment programs now also add QAC testing to their pretreatment permit compliance process.
To assist WWTPs in identifying these harmful chemicals, SPL has developed highly sophisticated legally defensible procedures for QAC testing, using liquid chromatography & tandem mass spectroscopy (LC/MS/MS). Each QAC test uses standard EPA quality control methods including blanks, laboratory control samples and duplicates to measures each QAC compound result against multipoint calibration curves. In addition to providing this sophisticated testing, SPL will also supply all of the materials needed for capturing representative samples. These sample collection items include properly cleaned bottles, custom, client specific chain of custody forms, and ice chests.
QACs can, and have, shut down both large and small wastewater treatment facilities because QAC concentrations inevitably reach toxic levels. These disinfectants then kill microbes essential to secondary stage wastewater treatment. This inability of the WWTP to properly perform secondary treatment allows untreated (or perhaps only partially treated) wastewater to be introduced into our local streams and rivers. While this can be a foreboding outcome, SPL can help ensure that your community’s WWTP avoids unexpected and sudden shutdown because of toxic QACs. Ask your representatives how they are testing for QACs. Ask them who they are using to test for QACs. Being informed citizens helps ensure our local bodies of water are safe. This is part and parcel of our community responsibility to our families, neighbors, and future citizens.
For more information, questions, or to submit a request for testing materials and supplies, please contact us at Kilgore.ProjectManagement@spl-inc.com.
Interested in diving deeper? Here are some of our favorite resources:
- Scientists warn of disinfectant overuse – Northwestern Now
- Quaternary Ammonium Compounds: A Chemical Class of Emerging Concern | Environmental Science & Technology (acs.org)