New Decentralized Wastewater Website Coming Soon!

DecentralizedWastewater.org will be launching soon as a new sister program of WaterOperator.org and PrivateWellClass.org.

Through a partnership of the Illinois State Water Survey and the Rural Community Assistance Partnership, the new website will provide training and technical assistance to wastewater professionals, onsite system owners, and managers of centralized and onsite/decentralized wastewater systems. We will host thousands of wastewater training documents, a calendar of training events, a regular webinar series, and more.

If you are seeking documents and events right away, you can check to see what is currently listed on the WaterOperator.org Documents Library and Event Calendar. Existing decentralized wastewater information will continue to be available on WaterOperator.org.

The program’s newsletter will be sent out monthly, and has launched already. You can sign up for the email list here, and check out the January, February, and March editions.

Please feel free to contact us at info@decentralizedwastewater.org if you have any comments, would like us to find something for you, or have information that will help other onsite/decentralized wastewater operators, installers, inspectors, and owners!

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

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.

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.