Emerging Contaminants and Your Onsite Wastewater Treatment System

When installed, operated, and maintained correctly, septic systems should not pollute groundwater or cause any danger to the drinking water supply. But the unfortunate fact is that pollutants and contaminants do make their way out of septic systems and into groundwater all the same. And this isn’t always to do with poor installation or maintenance — if a septic owner is putting things down their toilets and drains that aren’t meant to be treated by a septic system, these things become all the more likely to get into the groundwater. This is one of the reasons why making sure everyone knows the Three Ps of septic systems is so important! (That’s pee, poop, and toilet paper, of course).

A 2017 study in the journal Environmental Science & Technology showed that American septic systems are regularly depositing pharmaceuticals, consumer product chemicals, and other hazardous chemicals into the environment. Due to their presence in consumer and industrial products throughout society, such chemicals — often called contaminants of emerging concern or emerging contaminants — find their way into bodies and supplies of water in numerous ways, not just through septic systems. They can not only threaten public health by contaminating a human drinking water supply, but cause environmental problems for ecosystems and organisms as well. For instance, the feminization of male fish and fertility issues in other animals have been strongly linked to emerging contaminants.

This 2017 study suggests that besides emphasizing the need to avoid putting pollutants into a septic system, the best way to protect groundwater from septic contamination is keeping septic systems away from the aquifers and wells that supply drinking water. But, of course, many septic systems already exist in such a range and other solutions for preventing them from discharging too many emerging contaminants are needed.

While any chemical going into a septic system that isn’t one of the Three Ps is a contamination risk and absolutely should not enter a septic tank, some chemicals or contaminants will naturally be more of a cause for alarm than others. Right now, the pollutants society is likely most concerned about at large are PFAS compounds and microplastics, both of which have been found coming out of septic systems.

Though PFAS (Per- and polyfluoroalkyl substances, also commonly known as forever chemicals) have become a high-profile concern in more recent years, PFAS have been one of the most frequently detected compounds in drinking water wells since at least 2016, contamination which has been linked to septic systems.  

For more information on protecting groundwater from failing septic systems and forever chemicals, check out this article on the subject from SCS Engineers.

As for microplastics, the impossibly tiny bits of degraded plastic have been found everywhere from clouds to likely into human brains, and some believe septic tanks are the primary source of microplastics found in underwater drinking water reservoirs. The issue of microplastics in its totality certainly cannot primarily be blamed on septic systems, but figuring out how to decrease their presence in as many sources as possible is critical.

Another consideration with microplastics in septic systems isn’t just the environmental contamination — the buildup of solids in the system can also cause issues for the operation of the system. In fact, a 2015 Pumper Magazine article refers to microplastics as “tiny terrorists” in septic systems.

More to the point, microplastics are a type of solid that “remain[s] suspended are small rough to move readily through the screen and into the soil treatment area. If these solids are small pieces of organic material, they will break down or be consumed in the soil. However, if they are inert particles such as … plastics or other synthetic materials, they will not break down in the soil environment and will plug the soil pores, permanently reducing the ability of the soil to accept septic tank effluent. There is no fix when this happens other than replacement.”

Solutions to protect septic systems and the groundwater reservoirs they feed into from microplastics are hard to come by, short of emphasizing to septic owners the necessity of keeping everything but the Three Ps out of their systems and that they should try to buy fewer products containing microplastics to begin with.

How to Prepare a Septic System for a Large Event

Residential septic systems are designed to accommodate the wastewater from a specific number of people, typically judged by the number of bedrooms in the home. This normally doesn’t represent any issues for the regular residents, but the extra bathroom use necessitated by holding a large party or gathering can pose overload challenges for the septic system.

If a septic system is flooded by the overload of water from party guests in a concentrated timeframe, the overwhelming of the tank and drainfield could lead to sewage backups and flushing untreated effluent into the drainfield. In short, a quite possibly ruined party!

There are steps that homeowners can take to prepare for the impact on the septic system ahead of the party; mostly involving efficient use and management of water ahead of time. These are the steps advised by the septic education program at Michigan State University Extension:

• In the days leading up to the party, minimize the amount of water used for laundry, dishwashers, and showers.
• If the planned cooking is water intensive, do as much food prep and cooking ahead of time as possible.
• Rent a portable bathroom.
• Post bathroom rules to advise guests what can be flushed and other bathroom/septic safety tips.
• Have the septic system inspected and pumped before the party.
• Make sure that other outside sources of water, like eavestroughs or gutters, are routed away from the septic drainfield.

More Advice

• Things to Do to Save Septic System During Holidays | Crews Environmental
• A Guide to Holiday Guests and Septic Systems | West Coast Sanitation
• Why You Need to Prepare Your Septic Tank for the Holidays | A1 Tank Service
• Summer Gatherings and Your Septic System | All-Clear Septic & Wastewater Services

OSHA Requirements for Pumpers

It’s never a bad time for a refresh on the requirements of the Occupational Safety and Health Act (better known as OSHA). The act, passed in 1970, comprises a set of federal standards for workplace safety, but it also allows individual states to submit and operate their own safety plans and requirements. State plans may cover all workers in a state, or may only cover state and local government workers only. It is important to know which category your state falls under.

OSHA state plans covering private and state/local government workplaces:
Alaska, Arizona, California, Hawai’i, Kentucky, Indiana, Iowa, Maryland, Michigan, Minnesota, Nevada, New Mexico, North Carolina, Oregon, Puerto Rico, South Carolina, Tennessee, Utah, Vermont, Virginia, Washington, Wyoming

OSHA state plans covering only state/local government workplaces:
Connecticut, Illinois, Maine, Massachusetts, New Jersey, New York, Virgin Islands

No state plan, follows federal OSHA plans:  
Alabama, American Samoa, Arkansas, Colorado, Delaware, Florida, Georgia, Guam, Idaho, Kansas, Louisiana, Mississippi, Missouri, Montana, Nebraska, New Hampshire, North Dakota, Northern Mariana Islands, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Texas, Washington D.C., West Virginia, Wisconsin

State plans often don’t differ drastically from the federal OSHA plan, but the states of California, Michigan, Oregon, and Washington do have plans with substantial differences from the federal one.

Find your state OSHA office here >>

If you are in need of assistance in identifying and/or fixing workplace safety issues, most states do have consultation services available for free as part of the On-Site Consultation Program. Other OSHA programs workplaces can participate in include the Alliance Program, the OSHA Strategic Partnership Program, the Voluntary Protection Programs, and the OSHA Challenge Program.

Read more about the OSHA cooperative programs here >>

Keep in mind that the supervisor or crew leader of an onsite/decentralized wastewater work crew will typically be the OSHA competent person (unless there is a different employee specifically assigned to oversee safety). Whoever is in charge of safety, they must be able to identify critical issues, know and follow OSHA requirements, enforce a written safety plan, and create a culture of safety for the workforce.

The top reasons for accidents include rushing, poor concentration, and simply being in the wrong place at the wrong time. A comprehensive safety plan can help address some of these causes and minimize damages after accidents do occur.

For more:

• A Pumper's Guide to Federal and State OSHA Standards, Pumper Magazine
• Focus on Safety: Installers Need to Make Safety a Priority, Onsite Installer
• Occupational Safety and Health Administration

How to Abandon a Septic System

There’s a number of situations in which a septic tank/system might need to be abandoned: replacing it with a new system, connecting to a city sewer, or abandoning a property altogether. Septic tanks, cesspools, leaching pits, dry wells, and everything related must be properly cared for and not simply left as they are. Most important is to ensure that access for future discharge from the system will never be possible.

Many states or localities will have specific requirements for procedures on abandoning a septic system. For example, you can take a look at the Minnesota Pollution Control Agency’s guidance on abandoning a sub-surface sewage treatment system, where several state codes are referenced.

According to Sara Heger, septic educator at the University of Minnesota, there are three common practices for what to do with the empty tank:

1. Remove and dispose of the tank at a landfill.
2. Crush the tank entirely and backfill the hole. Water has to be able to drain through it, so it must be completely broken.
3. Fill the tank with a material like concrete that won’t let liquids flow through. There must be no risk of collapse in this scenario.

Basically, you never want to have an abandoned septic tank lying out exposed like in the photo above! Before codes and regulations for old septic systems came into place, it was common practice to simply leave the tanks where they were and forget about them. But this is quite dangerous. Old homes that were hooked into a sewer system long after construction should be inspected for old septic systems when sold.

An improperly abandoned septic system poses several possible risks. They could collapse into sinkholes, spread disease if untreated waste comes into contact with groundwater, or release toxic gasses like methane and hydrogen sulfide.

Be on the lookout for these signs of an abandoned septic system that is leaking, from B&B Pumping in Fort Worth: excessive weed growth on a lawn or algae on a pond, a perpetually soggy patch of lawn, an area of lawn that smells like human waste, unstable and sinking land, or pipes physically protruding from the ground.

Building over the top of even a properly abandoned septic tank isn’t a good idea, since sinking problems or leaked pollution could still occur if the area isn’t handled with care.

Costs of an Onsite Wastewater System

How much does a septic system cost in 2024?

There’s no simple answer — the cost of every single onsite treatment system is going to vary according to a number of factors. What we can tell you is this: as of 2024, HomeAdvisor.com, which aggregates home improvement and maintenance resources, lists the typical range of septic projects to cost between $3,484-$11,703.

The basic factors that HomeAdvisor identifies as driving the cost variations include the size, type, and material you need for the system. Be aware that these three key factors, as well as some others, can drive your costs up well beyond the upper end of that range.

Visit HomeAdvisor for a detailed breakdown of the ranges of costs for tank size, anaerobic vs. aerobic system tanks, types of alternative systems, material types, installation add-on costs, replacement costs, and more.

You can also get an estimate of the costs for your specific project’s needs, by entering information into their estimate tool. For the sake of accuracy and due diligence, it’s recommended to have at least 2-3 cost estimates before determining a final estimated price.

To find other septic professionals in your area, check NOWRA’s Septic Locator lookup tool. You’ll want to be able to list other septic professionals as references for your work, or to check the cost estimates with, when engaging with new potential clients. Networking is important!

So what do you do if you need help financing your septic project? Thankfully, there’s a number of resources available for assistance. You may want to visit the Financing page at the National Onsite Wastewater Recycling Association website — NOWRA has a long list of sites and organizations to visit for assistance, including the Environmental Protection Agency, the Department of Housing and Urban Development and the Department of Agriculture, and more.

Some other resources we would like to particularly recommend:

• The Rural Community Assistance Partnership (RCAP) provides technical assistance and support to rural communities across the country. Their Water and Wastewater Technical Assistance Program has a special focus area in onsite/decentralized wastewater. While RCAP’s national organization does not provide services directly, their regional offices can assist with coordinating help for your community. Contact RCAP here.
• The Financing Septic Systems module in the EPA’s Water Finance Clearinghouse. The module is for homeowners seeking information to support the operations and maintenance, repair, or new construction of septic systems.
• Septic at EPA — Along with a host of other septic-related information and resources, the EPA has funding sources listed by federal programs, individual states, and tribal communities.

Can A Septic Tank Float?

As crazy as it might sound, the answer is yes: Septic tanks can float out of the ground. Any buried structure will float when empty if it weighs less than the water that displaces it. That means that when installing any sort of septic system in an area with a high water table and/or that is prone to flooding, you must conduct buoyancy tests and determine if the system will remain stable.

Dr. Sara Heger, instructor at the University of Minnesota’s Onsite Sewage Treatment Program, has broken down the calculation to determine tank stability at Onsite Installer. The basic steps are below, but Dr. Heger’s walk-through explains each step in detail and shows example calculations. You will need to know the individual weights of the following: the empty tank, the minimum amount of water and media in the tank, the soil directly above the tank, and the maximum volume of water that is displaced.

Here’s the calculation:

1. Calculate the weight of water displaced by the tank (buoyant force B).
2. Calculate or look up the weight of the tank (WT).
3. Calculate the weight of the water in the tank (WW).
4. Calculate the weight of the soil cover (WS).
5. Evaluation of net forces.

So if your calculations indicate that the tank will float, what do you do then? Thankfully, there are anti-floatation measures that can be added to the system design plans. Perhaps the most basic is to use concrete, which weighs 85 pounds per cubic foot and can be added into the design in a few different ways. Some fiberglass tanks may also have an anti-floatation lip built onto them.

It’s important to consider that any anti-floatation measure will increase stress forces on the tank, so the tanks must be able to withstand the extra force. Read more from Dr. Heger at Onsite Installer on anti-floatation.

If you ever do need to deal with a flooded septic system, whether the tank has emerged from the ground or not, refer here:

• “Faced with a Flooded Septic System?” also from Dr. Heger at Onsite Installer
• “Protecting a Septic System During and After a Flood” at WaterOperator.org
• Contact the Onsite Sewage Treatment Program at UMinn.

Businesses on Septic Systems

If a business is in an area that does not have a public sewer system, or, if the business will generate a higher flow of additional wastewater than a sewer system will be able to handle, a commercial septic system will be necessary. This type of system, also called a large-capacity septic system, is defined by the U.S. Environmental Protection Agency as "a septic system that receives solely sanitary waste from either multiple dwellings or a non-residential establishment that has the capacity to serve 20 or more people per day."

The wide variety of facility types that a large-capacity system could service include schools, religious institutions, office and commercial buildings, shopping malls, hotels, restaurants, convenience stores, and more. Unlike residential septic systems or non-residential systems serving fewer than 20 people per day, the EPA does regulate large-capacity systems in order to protect underground drinking water sources.

Fundamentally, though, a septic system on a business property works in fundamentally the same way as a residential system, just on a larger scale. To keep up with the higher volume of wastewater the system will be handling, large systems will require more frequent pumping, maintenance, and service to ensure they operate properly for as long as possible. Business owners managing water use so that the system is not overwhelmed will also help keep the system in good working order.

Again, similarly to residential systems but on a larger scale, the costs of both installation and operating large-capacity systems will vary widely based on the individual factors of the commercial location and performance needs for the system.  

There are some differences to keep in mind for large-capacity systems. While these systems still only handle sanitary waste (so no industrial waste allowed), there are still different types of wastes produced by commercial buildings that their large-capacity septic systems will need to be able to handle. So they’ll need additional design components — such as grease traps in restaurants to keep fats, oils, and greases (the notorious FOG!) from clogging up the plumping — and more specialized maintenance and service.

Multiple types of septic systems can be used for a commercial installation. AAA Pumping Service recommends sand filter systems, pressure distribution systems, evapotranspiration absorption systems, and cluster systems as well-suited for commercial properties. (A cluster system would serve multiple nearby businesses/commercial properties).

Note: Mention of commercial entities who share educational information does not constitute an endorsement.

Additional Reading

• Large-Capacity Septic Systems | U.S. EPA
• Best Septic Systems for Your Commercial Property | AAA Pumping Service
• Five Facts About Commercial Septic Systems | Moon Site & Septic
• Five Things to Know About Commercial Septic Systems | World Construction Today
• “Design Concerns with Restaurants, Convenience Stores, and Commercial Waste” Presentation | Onsite Installer

Nutrient Control for Wastewater Treatment Plants

The control of the discharge of nutrients (nitrogen and phosphorus) from municipal wastewater treatment plants is critically important to the achievement of the water quality goals of the Clean Water Act. Through National Pollutant Discharge Elimination System (NPDES) permits, effluent limitations on the concentrations of nutrients are set to support designated uses, based on state water quality standards.

We have 479 resources (and counting) on Nutrient Control in our Documents Database that provide valuable information on this topic. You can search for documents about resource recovery as a viable nutrient control alternative, phosphorus removal, costs associated with nutrient pollution, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Nutrient Control within our database just select "CATEGORY" in the dropdown then choose "Nutrient Control." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Webinar Recording: Cybersecurity for Wastewater Operators

Watch this webinar recording to discover some of the most helpful cybersecurity resources and to learn how to use our search tools at WaterOperator.org to find additional resources and training events. This is the first webinar in our new series for wastewater operators!

The webinar answers questions such as:

• What is WaterOperator.org and how is it a useful tool for wastewater professionals?
• What are the best resources we have relating to cybersecurity in the water and wastewater sector?
• How can you find more cybersecurity resources and other similar resources on WaterOperator.org?

This free series will cover topics relevant to wastewater operators, including funding, asset management, compliance, and water quality. Upcoming events in the series include:

• Source Water Protection for Communities with Decentralized Wastewater (April 23)
• Funding Wastewater Infrastructure Projects (June 25)

Certificates of attendance for each session will be delivered upon request. Check with your certification body for acceptance criteria.

Here is the recording of the first webinar, held in February 2024. We cannot provide certificates of attendance for watching the webinar recording.

Biosolids & Activated Sludge Treatment

Biosolids are the nutrient-rich organic materials resulting from the treatment of sewage sludge. Often times, they are the solids removed from the bottom of a lagoon, that are applied to farm fields as fertilizer.

We have 379 resources (and counting) on Biosolids in our Documents Database that provide valuable information on this topic. You can search for documents that cover the types of lagoon sludge and how to calculate sludge volume and the volatile portion, what are nutrients and how they are removed, how to deal with accumulated sludge in a wastewater lagoon, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Biosolids within our database just select "CATEGORY" in the dropdown then choose "Biosolids." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.