THE SHUBAEL POND PROJECT
The majority of Cape Cod’s water quality problems caused by excess nutrient pollution can be traced back to septic systems. Although traditional Title 5 septic systems remove pathogens and other components from wastewater that can be harmful to human health, these systems were not designed to remove large amounts of nutrients, including nitrogen. Innovative/alternative (I/A) septic systems to reduce nitrogen in household wastewater have been developed and approved by the Massachusetts Department of Environmental Protection (MADEP), but to date none of the approved systems have achieved the nitrogen reduction akin to a wastewater treatment plant. BCWC is working to install, test and advance systems that can perform at a level comparable to municipal sewering, so these I/A systems can be approved for general use and made available to homeowners and builders.
By installing a cluster of up to 40 systems in one neighborhood, BCWC can demonstrate the effect of a group of these systems on removing nitrogen in groundwater. . In addition, this cluster installation will help the NitROE system obtain general use approval by MADEP. After drilling wells and testing the groundwater at four different sites, BCWC selected a neighborhood abutting Shubael Pond for this (or test) project. Not only are the groundwater conditions ideal for monitoring the cumulative impact of these systems, but this pond was also closed for most of the summer in 2019 due to a cyanobacteria bloom.
While only one system will be initially tested, BCWC plans to expand and test other systems that have met certain criteria in the future. These criteria include achieving a 90% reduction in nitrogen, requiring minimal maintenance, and the ability to function as a Title 5 system in the event of a power failure. To date, KleanTu’s NitROE system is the only system that meets all criteria for this project.
What Is The Shubael Pond Project?
BCWC and our partners have selected a neighborhood near Shubael Pond as the location to install and monitor next generation septic system technology. This area has many attributes that make it an important site.
• Hydrologic conditions
• Approximately 350 homes contribute to the Marstons Mills subwatershed.
• Many homes have existing septic systems that are near the end of their expected useful life of 20 - 25 years.
• Groundwater flows into this 53-acre kettle pond, which was closed throughout the 2019 summer season due to harmful cyanobacteria algal blooms.
• Many homes are populated with year-round residents.
• This location is not scheduled to get municipal sewering for decades.
• The site is located within the Three Bays watershed, which is Barnstable’s most troubled and the Cape’s third worst in terms of nitrogen overload.
The town of Barnstable has identified this area as part of its recently filed Comprehensive Wastewater Management Plan (CWMP). Their 30-year plan calls for expansion of the existing municipal treatment plant to service an additional 9,800 households (out of approximately 25,000). Initial cost estimates for this expansion are $1.1 billion, including finance costs. Construction costs alone were pegged at $87,000 per household. Most of these costs would be covered via a variety of revenue sources, leaving a smaller amount that the individual homeowners are responsible for.
The Shubael Pond Project seeks a lower cost alternative and is designed to demonstrate that an I/A septic system can achieve levels of mitigation of nutrients, like nitrogen, that are equal to those of our municipal treatment facility. At scale, we hope to prove that these systems can be delivered for approximately 25% of the cost of municipal expansion. In addition, longer term operating and maintenance costs should be substantially lower. One easy metric to consider is that a gallon of water weighs 8.34 lbs. Even today, pumping thousands of gallons of wastewater to the central plant comes at great expense, an expense that will rise dramatically with system expansion. On-site treatment eliminates that requirement.
This project will be grounded in data collection and analysis. For the first time, we will be able to collect data from underlying groundwater that will allow us to compare results for individual, distributed wastewater treatment versus the concentrated treated wastewater injections which now occur. Expansion of municipal scale wastewater disposal is one of the most challenging issues for every community.
Time is clearly of the essence given the well documented deteriorating conditions of our local waters. Lakes, ponds, estuaries and drinking water all need attention and addressing the main source of our problem, Title 5 septic systems, is the answer. This project may identify a tool that will allow our community to tackle the challenge more quickly and at a far lower cost.
However, much work needs to be done. The following criteria have been identified for an alternative system:
• High performance standards for the mitigation of nitrogen and other contaminants;
• Compelling installation, maintenance, and operating costs;
• Gravity driven operations with modest power requirements;
• Ability to operate at current Title 5 septic system standards in the absence of any power;
• Real time performance monitoring.
These and other criteria will be outlined in a “Request for Proposal” (RFP) that will be forthcoming as we move forward with this project.
Our efforts at Shubael Pond are not limited to septic systems, although we believe that they are the source of approximately 85% of the water-related issues. BCWC will also work closely with our partners to identify, document and remedy stormwater related issues. Further, we intend to work closely with individual stakeholders within the community to develop best practices for yard maintenance, fertilizer use, and landscaping alternatives that can help decrease nutrient overload conditions in the pond. This project is multifaceted with many additional considerations and potential benefits.
Some of the most important work in this effort will be the information we will gain by monitoring the groundwater. How will the groundwater data in this I/A septic system installation compare to the current treatment approach of centralized wastewater treatment? What changes will take place in the groundwater as it travels one to four feet a day carrying treated effluent from the septic system? How does this compare with the resulting concentrated “plume” of effluent produced on a municipal scale?
Typically, on the Cape, this treated effluent is injected into the ground in high volume. For example, in Boston, wastewater is disposed of via an outfall pipe into Massachusetts Bay. We believe that successfully distributed treatment of our wastewater may be a far better choice both environmentally and financially.
The financial challenges are not trivial. To protect both our recreational waters and our drinking water, we estimate that the Cape may need over 100,000 of these systems in addition to the expansion of municipal systems. BCWC is working closely with The Nature Conservancy to identify financing alternatives. Many possibilities exist: private “impact” investments, local, state and federal funding, tax credits and water usage funding are all in the mix.
Operations and maintenance must be consistent and reliable. Our goal is to develop a model that allows individual homeowners, and the community at large, to know that the systems installed are operating to the expected standards. To date, the earlier generation of alternative septic systems have largely failed in this regard. The plan is to address this issue by developing a model that will allow the same level of performance we have all come to expect from our existing utilities and trusted service providers.
We have ambitious goals and the Shubael Pond Project is just the beginning. We have the funding to get started thanks to your continued support. Although these first I/A systems may be fully subsidized, we will need to continue to raise more money and work hard to build a sustainable financial model.
How The Project Team Chose The Shubael Pond Site
Assessment of Hydrologic Conditions in the Three Bays Watershed in Support of Nutrient Management Activities, Cape Cod, Massachusetts
From the New England Water Science Center
In 2019 the USGS began a partnership with the U.S. Environmental Protection Agency (EPA) Office of Research and Development (ORD), EPA Region 1 Southeast New England Program for Coastal Watershed Restoration (SNEP), Barnstable Clean Water Coalition (BCWC), and other stakeholders to conduct hydrologic monitoring and assessment in support of multifaceted nutrient-management activities in the Three Bays watershed on Cape Cod. Hydrologic monitoring will be used to evaluate the effectiveness of non-traditional technologies such as innovative and alternative (I/A) septic systems and permeable reactive barriers (PRBs) for reducing groundwater nitrogen concentrations and loads.
The Three Bays watershed (fig. 1) has been selected by EPA ORD as a location to promote the development and implementation of innovative nutrient management solutions in a southern New England coastal setting. Similar to other areas on Cape Cod, Three Bays is a groundwater dominated watershed in which substantial fractions of the total nitrogen load to surface-water bodies are delivered by groundwater. Consequently, understanding the groundwater-flow system (for example, flow directions and rates, depth to groundwater, subsurface geologic conditions, and water quality) is important. Although the groundwater-flow system in the watershed is generally understood from regional modeling studies, assessments of local groundwater conditions will be needed for most of the technology demonstration projects.
Current (2020) work is focused on identifying sites in the watershed that are potentially favorable for demonstrations of I/A septic systems at the neighborhood scale. More information about I/A systems is available at the Massachusetts Alternative Septic System Test Center (MASSTC) web site (https://www.masstc.org/). The effectiveness of new I/A system designs will be evaluated for individual systems installed in the watershed (for example, seasonal measurement of influent and effluent nitrogen concentrations for individual systems) and a group of 30-50 systems clustered in a selected neighborhood. The goals of the neighborhood-scale demonstration are to determine cumulative changes in groundwater quality, primarily concentrations of nitrate, and quantify changes in groundwater nitrogen loading to downgradient surface-water receptors in response to installation of clustered I/A systems.
To select a neighborhood for the demonstration, USGS conducted an analysis of hydrologic and land-use characteristics of the watershed in the fall of 2019 and recommended four sites for preliminary site characterization (fig. 1). In November 2019, USGS conducted the preliminary site-characterization field work in collaboration with EPA ORD. Vertical profiles of generalized geologic conditions and groundwater quality from well clusters installed at the four sites are shown in Figure 2. Based on the results of this work, a neighborhood adjacent to Shubael Pond in the northeastern part of the watershed (fig. 1) was selected for the I/A system demonstration.
Planned future work in the Shubael Pond neighborhood will include additional focused site characterization to better define local hydrologic and water-quality conditions followed by installation of a larger groundwater and surface-water monitoring network. The monitoring network will be sampled periodically to determine (1) baseline (pre-intervention) water-quality prior to I/A system installation, and (2) cumulative effects of installed I/A systems on groundwater-quality and nitrogen loading over time. Knowledge of local hydrologic conditions developed from the site characterization work will be used to inform the locations and orientation of the clustered I/A systems and monitoring network to optimize detection of changes in groundwater quality. Periodic sampling of the monitoring network likely will continue for several years after installation to account for the relatively slow movement of groundwater and associated response to I/A system installation.
In addition to the I/A system demonstration, USGS may provide hydrologic support for other EPA-led nutrient management activities in the watershed. Other potential nitrogen-reduction projects include installation of permeable reactive barriers, pond dredging, and restoration of cranberry bogs and wetlands. Baseline information needed to support these activities generally includes streamflow and pond-level monitoring; water-quality data for surface waters (rivers, ponds, embayments) and groundwater; and local-scale hydrogeologic data consisting of groundwater levels and flow directions and subsurface geology.