The Enterprise Mashpee
By: Sam Drysdale
Mar 18, 2022
New Septic Systems Promising In Protecting Upper Cape Water Systems
Outdated and environmentally unfriendly septic systems and cesspools are the norm on Cape Cod. Although most people would rather avoid the topic of where their waste goes after it has been flushed, the Massachusetts Alternative Septic System Test Center is not afraid to take on the issue directly.
Located on Joint Base Cape Cod, the center was founded in 1999 to test and research innovative/alternative, or I/A, septic systems.
Traditional septic systems, which represent most of the wastewater infrastructure on Cape Cod, have contributed to the contamination of both fresh and saltwater systems through poor nutrient regulation.
Nitrogen and phosphorus in human waste leak from septic tanks into the groundwater, which then flows into the Cape’s bays, estuaries, rivers and ponds.
Saltwater generally lacks significant amounts of nitrogen, so when the nutrient is introduced to the system, it encourages the growth of algae and bacteria that thrive off the new nutrients. Algae blooms cause oxygen depletion, which kills fish, shellfish, eelgrass beds and other important life forms. In freshwater systems, phosphorus flows have the same effect.
All four Upper Cape towns saw significant cyanobacteria blooms in their lakes and ponds during the summer of 2021. The blooms can produce toxins that are harmful to people and animals.
As water quality worsens on the Cape—and for many other places throughout the country—MASSTC has been researching, testing and inventing new I/A septic systems that are designed to treat wastewater to prevent excess nutrients from entering the groundwater.
“What we try to do here at the test center is vet the technology and identify the best ones,” said MASSTC director Brian Baumgaertel, a Mashpee resident who is also the chairman of the Mashpee Board of Health. “We may do the testing here or we may look at testing done in other areas of the country, but we’re trying to figure out how to broaden the toolbox for Cape Cod.”
Several Cape towns have begun long-term sewer projects to address the negative effects of wastewater on their waterways. Many of these projects have wide public support, as sewers are considered “the gold standard in wastewater treatment,” Mr. Baumgaertel said.
However, the director said the I/A systems being developed at the septic research center may offer supplemental, or even alternative, solutions.
In addition to ongoing sewer discussions in Bourne, Falmouth is projecting that the areas of Teaticket and Acapesket will be sewered in 2026; Sandwich residents voted last year to add 20,000 feet of sewer pipe to their system; and in Mashpee, where significant time and money are being invested in the town’s sewer project, residents may not begin hooking up to the system until well into 2024.
Once these steps are taken, there will still be plenty of work ahead for those towns to connect residences and commercial spaces to the system, which could possibly take decades.
As homeowners wait for the sewer lines to reach their neighborhoods, some may consider an I/A system to mitigate nutrient contamination coming from their property, Mr. Baumgaertel said.
One of the tools in the wastewater management “toolbox for Cape Cod” is the “layer cake” I/A system, which former MASSTC director George F. Heufelder of Falmouth pioneered.
Traditional septic tanks drain into a leach field—a shallow area of land where the soil is used to naturally treat and disperse wastewater as it moves through the porous material.
“Leach fields are great at taking the incoming ammonia from our waste and turning that into nitrate, which is what gets into our groundwater,” Mr. Baumgaertel said. “The difference with the layered system design is rather than letting that nitrate go out the bottom and into groundwater, it introduces another layer of material underneath.”
MASSTC is currently testing several different layer cake systems. Some have woodchips underneath the leach field, which help convert the nitrogen to gas; others use woodchips and sand layers; and some are being tested with an impermeable liner to keep the leach field saturated and without oxygen to prevent ammonia from converting to the more harmful nitrate.
Walking around the center, most of the research is invisible.
“This one over here is the ‘bathtub’ design with the impermeable liner,” Mr. Baumgaertel said during a tour of the center, pointing at a section of grass on the center’s two-acre property. He pointed to another grass area. “There’s three tanks here in this one—not that you can tell—but there’s a packed aerated gravel bed and woodchips here.”
A standard state-approved septic system filters up to 35 percent of the nitrogen out of wastewater, Mr. Baumgaertel said. Many of the systems MASSTC is testing remove 85 to 90 percent.
The center is working with the Town of Barnstable, the US Environmental Protection Agency and the US Geological Survey and Nature Conservancy on a Barnstable Clean Water initiative in Marstons Mills.
The center has tested groundwater flows in the area and is installing 12 I/A systems into people’s backyards in the neighborhood. The center has installed 11 of the 12 layer cake systems so far, Mr. Baumgaertel said.
“It’s been a really good, informative process,” he said. “The first layer cake design we wanted to try in the field was the cheapest, easiest-to-install system. What we found is that it doesn’t really have the longevity we were hoping for, since sometimes simplest isn’t always the best.”
The center is planning to start putting new designs into people’s backyards to test more-complex systems in the field. The hope is to install four new I/A systems over the next few months.
“If we can install a whole neighborhood of these systems, and we monitor the groundwater, can we see real impacts? Can we practically use I/A systems rather than sewers?” Mr. Baumgaertel said.
The center has worked on several other projects in the area as well, such as in West Falmouth, where it collaborated with the Buzzards Bay Coalition to install a variety of I/A systems into 20 to 30 locations.
One of the center’s goals is to research and test different types of I/A technology to increase competition of these systems on the market and help drive down the cost for homeowners, Mr. Baumgaertel said.
A full replacement of a standard septic system with an I/A system can cost about $38,000, although that cost ranges.
In the West Falmouth project, the coalition and the center discovered that they could retrofit old systems with I/A technology without having to replace everything, coming in at about $27,000.
“It’s a high cost for people,” Mr. Baumgaertel said. “But compared to sewer projects, if you look at Mashpee Phase 1, it’s $54 million just for the first phase. So, if you do the basic math, that’s like $130,000 per parcel that’s going to be connected to that, whereas this could actually be sustainably cheaper.”
About half of the $54 million designated for Phase 1 of Mashpee’s sewer project will go toward a wastewater treatment plant, which the town’s sewer commission hopes will serve more homes than the original 420 hooked up to the system in the first phase.
Regardless of whether it is through sewering or I/A systems, Mr. Baumgaertel said something needs to be done about the Cape’s wastewater problems.
“We’re doing research right now on water reuse, not necessarily ‘toilet to tap’ yet, but you could potentially use it for toilet flushing or irrigation,” he said. “But what’s funny is that ‘toilet to tap’ is what we’re doing right now; we just don’t realize it. Our wastewater goes into the ground, and then we take it back out. We’d better make sure it’s clean.”
A standard state-approved septic system filters up to 35 percent of the nitrogen out of wastewater. Many of the systems that the Massachusetts Alternative Septic System Test Center is testing remove 85 to 90 percent.
The Enterprise Mashpee – New Septic Systems Promising In Protecting Upper Cape Water Systems