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Kurt Bihler: “I’d like to give Sara Heger a Big Gold Star for this article. It sums up nicely what I’ve told people for years.”

Septic Care: Testing for Quats

These salt compounds can accumulate and negatively affect your customers’ septic systems.

A “quat” is a shorthand term for a type of chemical known as a quaternary ammonium compound. Put in the simplest terms, a quat is a complex organic salt compound used for multiple applications. Despite the similarity in naming, a quat is not and does not contain either ammonia or ammonium ion. The name comes from the similar chemical structure to these other molecules.

Where will you find them?                                                                                                        
There are literally hundreds of quats in existence and in common use in home, commercial and industrial products. A review of the ingredients of many products will reveal their presence, if you are familiar with the ingredients list. Unfortunately, most of the time the names given do not include the term quat or quaternary ammonium but instead use complex and lengthy chemical names. The amount of quats has been on the rise in homes and businesses primarily due to the requirement to reduce the use of phosphorus in cleaning products. Initially this seems like a good idea as excess phosphorus in the environment leads to increased algae growth in many water bodies. The problem is that quats can be toxic to the microbes in our septic systems and in the soil. In commercial systems, large amounts of quats can end up in the wastewater stream due to hand dishwashing and toilet cleaning.

Quaternary ammonium salt compounds are commonly used in the following applications:

  1. Antimicrobial disinfectants commonly found in antibacterial soap, toilet bowl cleaner and other household disinfectants. Examples are benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dofanium chloride,tetraethylammonium bromide, didecyldimethylammonium chloride, ammonium chloride and domiphen bromide.
  2. Food service establishment sanitizers. Most national restaurants, convenience stores and grocery chains require the use of quat sanitizer.
  3. Surfactants (compounds that make it easier to loosen or dissolve solids into liquids, commonly used in cleaners to release dirt into watery solutions). This includes automatic dishwashing and laundry detergent.
  4. Fabric softeners (both liquid for use in washing machines and the dry form for use in dryer sheets).
  5. Antistatic agents, usually found in shampoos.
  6. Septic tank additives used to control septic odors by killing bacteria. This objective, however, runs counter to the purpose and function of septic tanks (promoting anaerobic bacterial growth).

It is important to note that the quat used in one application will not necessarily be effective in other applications. For example, dryer sheets (sulfur-containing quaternary ammonium salts) will not act as antimicrobials (long alkyl chain quaternary ammonium salts).  A good resource to find the active ingredient in a product is the Department of Health and Human Services Household Products database.

The problem
It is well understood that disinfectants or sanitizers in high concentrations can kill off the good microbes in our septic systems. Quats compounds are very stable and the chemical bonds are difficult to break, so they have a long biocidal effect. Quats are stable water-soluble organic salts and tend not to break down. In fact, they are used as preservatives due to their bactericidal nature and exceptional chemical stability. In a study of RV wastewater, quaternary ammonia was shown to slow down the rate of oxygen uptake by the microorganisms and be toxic to microorganisms (Hindin, 1994).

In anaerobic environments, they have been found to be inhibitory at 5-15 mg/L and in aerobic conditions at 10–30 mg/L for BOD and 2–5 mg/L for nitrification.  Another study by Gross (1987) evaluated the impacts of several chemicals including Lysol, which contains alkyl dimethyl benzyl ammonium chloride, one of the most widely used quats. The purpose was to determine the amounts of specific household chemicals required to destroy bacteria populations in individual domestic septic tanks using both lab and field studies. A Lysol concentration of 5.0 mL/L destroyed the bacteria in the domestic septic tanks. This corresponds to 5.0 gallons of Lysol in a 1,000-gallon septic tank. The bacteria population recovered to its original concentration within approximately 60 hours (2 1/2 days). Although it is unlikely that a property owner would use 5 gallons in a home at one time, the cumulative impact of these chemicals can impact system performance.

Unlike bleach, quats are odorless and colorless. There are quat test strips that will show if the cleaning products in use contain quats or not and at what concentration. Typically what they will be measuring is benzalkonium chloride, which is used in commercial kitchen sanitation. Most of the test strips are designed for use in sinks to measure concentrations in the range of 200 mg/L, but we are interested in much lower levels. Therefore be sure to get strips that can read down to 5 mg/L, use a Hach kit or have an analysis done at a lab (ASTM Method D5806-95).

The use of quats should be avoided. For in-home use, natural-based cleaners such as baking soda, vinegar and borax are preferred along with limited amounts of chlorine and/or other biodegradable cleaners.

In commercial kitchens, oxidative sanitizers like bleach or iodine are recommended over quaternary ammonia. Another potential option is a botanical disinfectant called Benefect which is on the EPA registered disinfectant list. Hydrogen peroxide breaks down to water and oxygen and does not leave harmful residues. Peroxide sanitizers offer an alternative to more toxic cleaners, because they do not introduce irritating fumes into the air. High-temperature dishwashers may be another alternative to consider along with commercial dishwashers using chlorine. Many national or regional chains will not stop using quats. For these sites, consider the use of NeutraQuat, a QAC neutralizer for wastewater systems.

About the Author
Sara Heger, Ph.D., is an engineer, researcher and instructor in the Onsite Sewage Treatment Program in the Water Resources Center at the University of Minnesota. She presents at many local and national training events regarding the design, installation and management of septic systems and related research. Heger is education chair of the Minnesota Onsite Wastewater Association (MOWA) and the National Onsite Wastewater Recycling Association (NOWRA), and serves on the NSF International Committee on Wastewater Treatment Systems. Send her questions about septic system maintenance and operation by email to



Please note:

This is a general approximation of loading rates. Actual loading rates for MBR filtrate is calculated by performing a double-ring infiltrometer test on the soil to be used.



Distributed Alternative to Public Sewer

Opening: Sewers can be described as mainframe computers, and rightfully so; old mainframe computers were an example of “centralized” computing, and have a similar history of usage. At the time that mainframes dominated the marketplace in 1950, much of the sewer infrastructure in the Midwest went into place.

Fast-forward 65 years later. The landscaping of computing is much different due to radical, new innovations like “servers” and hand-held devices, all with greater individual computing power than the mainframes of the past.

Centralized sewering systems allowed for permanent, distributed water management. Large centralized sewering systems are thought to be more efficient with energy, treatment, and transfer. Soil-based wastewater treatment disposal methods have never been able to offer this. Small-scale effluent pumping systems, which use pumps and small-diameter pipes to transfer wastewater, try to mimic this approach. However, they do not offer the same economic advantages that large sewering systems do.

Why only two choices? Because many people have not been aware of a viable option for permanent, distributed water management through the soil until now.

Centralized Sewering Systems: From time to time, municipal and industrial wastewater treatment plants experience operational problems such as poor settling, foaming odors, loss of nitrification, poor effluent quality and maintenance issues. The smaller the treatment systems, the more likely that these issues will occur.

With centralized sewering systems, there has always been difficulty in managing strength, flow, and toxins. When you add other items like grinder pumps or STEP systems to the small community treatment systems, it continues to add ongoing maintenance costs.

Keep in mind, water weighs 8.34 pounds per gallon. It takes an enormous amount of energy from mechanical devices to move this weight from one side of the town to the other, not including leakages, water loss, and other fluctuations. This is before treatment has even begun. Even adding load-balancing technology to increase efficiency and decrease maintenance is not a viable solution for smaller systems.

The USEPA imposes significant fines for noncompliance with discharges. With small flow distributed systems, there is definitely greater financial risk of noncompliance of one’s wastewater management system.

NPDES permits are typically renewed every five years. With situations outside of the control of the community, i.e. impaired water designation caused by higher limits of bacteria, dissolved oxygen, soluble organics, and nutrients (nitrogen and phosphorous), the design of the entire plant may need to be upgraded with new compliancy equipment to address these new standards. In many cases, the cost of upgrading the plant may exceed the cost of building the original plant.

Soil-Based Onsite Systems are designed to fail:  Soil-based onsite systems are mainly used in rural applications with a lot of land and favorable soils. However, soil has a limited capacity to hold suspended solids, organics, and water. There are many variables to sizing, installing, and maintaining a soil-based system; and this further complicates the engineering of a reliable system. Based on pore size and volume, soil-based systems can be calculated for sizing until the moment of future inevitable failures.  For example, a residential 300 GPD with typical loading of TSS 100 mg/L, 100 mg/L BOD, and a disposal area of 3000 ft(2) would take 14 years to fill the soil and thus biologically fail.  With the same size 300 GPD system and 3000 ft(2) drainfield used for a commercial (typical high-strength loading of TSS 1000 mg/L and 1200 mg/L BOD) application, the system would fail in 1.3 years.

The septic tank holds the floatable and settleable solids, but does not remove suspended solids or soluble organics, and does not mitigate toxins. With aerobic treatment, a larger percentage of suspended solids are removed, and a large percentage of soluble organics are converted to settleable solids also being removed from the wastewater. This only occurs when toxins are below operating limits.

Whether soil-based or aerobic, the disposal field will eventually plug and seal off, causing failure.

Toxins come from everyday household cleaners. In 2010, the USEPA banned the use of phosphates in household cleaners in order to prevent algae blooms in streams and rivers, which degrade water quality. The cleaning products industry had to replace phosphates with another chemical, and the cheapest alternative were quaternary ammonium cations (quats). Quats are designed to kill bacteria and thus disrupt any biological treatment process, whether in a centralized, aerobic or soil-based treatment system.

When you fill up your disposal field with garbage every day, it will eventually run out of room. Thus, soil-based treatment systems can only be temporary until they fail.

Solving the “Centralized vs. Decentralized” Dichotomy: Onsite membrane bioreactors are based on science and physical separation of the pollutants and pathogens to create filtrate. Even though we use onsite water dispersal, these systems are not soil-based technologies, but they replace the idea of using septic systems or hookups to a centralized sewer network. For onsite water recycling systems, three things are important: 1) quality of filtrate; 2) quantity of filtrate; and 3) rate of filtrate delivery.

Onsite Water Recycling Systems: The BioBarrier® water recycling system provides precise process control for complete treatment before dispersing the filtrate. The only factor in sizing is hydroconductivity so water doesn’t surface. Even if this occurs, there is no public health risk because the water is free of bacteria. The remedy would be a small, inexpensive addition to the dispersal area.

This is how these sub-surface, dispersing, water-recycling systems can be based solely on hydroconductivity, can last for the life of the home or commercial property, and thus are as permanent as public sewers with zero money for up-front cost of piping, EPA permitting, and pump stations with corresponding sewer systems.

Quality of Filtrate: The soluble organics, pathogens, and suspended solids are all below detectable limits. This means no change in hydraulic conductivity over time. Because of the lack of organics and solids, the soil’s absorption rate remains constant over time.

Quantity of Filtrate: The size of dispersal area is the same, regardless of the influent strength of wastewater, whether domestic, commercial, or even extremely high-strength waste. If hydraulic overloads occur, the excess will be trapped and monitored with high-level alarms and process control strategy. The system overcomes the rate by shutting down and alerting maintenance, and therefore, the dispersal area can never be hydraulically overloaded beyond its design limits.

Rate of Filtrate Delivery: This is based on discharge of restricted flow, which will always be less than the filtration rate of the dispersal area, whether it’s from the most permeable to the least permeable conditions.

Using the BioBarrier is economically, ecologically, and, from a public health standpoint, is safer than either centralized sewering or soil-based treatment technologies. Lot size has always been limited by availability of public sewer or land for soil-based treatment. The BioBarrier’s filtrate dispersal area is smaller than the disposal area of a soil-based treatment system, typically one-tenth the size.

Conclusion: The BioBarrier is the lowest risk for distributed or onsite systems for total water management.

Enabled the Reclamation of Illinois Strip Mine into Recreational Resort

Infiltrator CS55 Goose Lake Ranch IL 7-2015ROverview

Goose Lake Ranch is an 800 plus acre reclaimed strip mine property in Fulton County, Illinois consisting of over 50 lakes that are famous for incredible fishing. The Herman Brothers family is rehabbing an existing campground, adding resort cabins, and 90 campsites and they plan to film a TV series on the property.


Since the property consists almost completely of reclaimed coalmine spoils and lakes in close proximity to each other, it posed some extremely challenging wastewater situations. The inconsistent soils, numerous lakes and drastic elevation changes challenged system designers along with stringent new code requirements.

System Design

NSF350 water recycling membrane systems were designed to meet the challenge the include Bio-­Microbics® BioBarrier® Membrane (MBR) systems installed within Infiltrator IM-­Series Tanks. The numerous MBRs are either 500 or 1000 GPD units and are built to suit the location with single units for individual cabins and 1000 GPD MBRs serve clusters of resort cabins, beach houses, a store, and a banquet hall. Installing the Infiltrator IM-­Series Tanks allowed the units to be constructed in a shop to specifications and then delivered and installed around the property as needed without requiring a heavy boom truck thus saving substantial expenses.

EZflow by Infiltrator was used for the treated effluent dispersal fields, eliminating heavy trucking and the spreading and compaction challenges of stone. The Infiltrator IM-­Series Tanks are also used for trash and pump tanks and the dispersal fields are time dosed by Aquaworx IPC Control Panels.

A blower outside the tanks in a plastic enclosure blows air to scour the membrane to keep it clean which keeps the biomass alive and growing. A 1.5 amp marine pump is attached to each MBR and very slowly pulls the recycled water out and then transitions to gravity flow to the EZflow dispersal fields.  ~ Infiltrator Water Technologies

Revised Bio-Microbics® BioBarrier® approval in Illinois; the the result of 2 years experience and over 50 units installed!

High-tech, green, wastewater recycling is here!

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