- Treating wastewater properly is essential to both human and environmental health. The average house produces between 60,000 and 65,000 gallons of wastewater each year or about 170 gallons per day. In addition to the pollutants we regulate in wastewater — nitrogen and pathogens (viruses and bacteria) — it now includes an increasingly complex cocktail of pharmaceuticals, personal care products, and hazardous chemicals flushed into the system. Wastewater from each residence annually releases about 13.5 pounds of nitrogen into the groundwater and the downgradient ponds, unless we act to reduce it or to intercept it before it arrives.
The Massachusetts Department of Environmental Protection regulates wastewater treatment in the Commonwealth, setting standards for the installation and operation of facilities at all scales, focusing mainly on public health. Local Boards of Health may adopt more restrictive regulations.
Wastewater is the largest locally controlled source of nitrogen pollution to our groundwater and surface waters. Coastal salt ponds are more sensitive to nitrogen than people, so we need additional measures to limit nitrogen pollution beyond the requirements in place to ensure human health.
Wastewater leaving the septic tank contains about 35 parts per million of nitrogen. Natural nitrogen uptake and bacterial conversion to nitrogen gas lowers the septic system nitrogen by about 25% by the time it reaches a coastal pond.
Centralized wastewater treatment facilities fed by sewage collection systems are most suitable for higher density areas and can remove about 90% of the nitrogen.
Satellite treatment plants are most suitable for outlying, higher density areas, and remove up to 75% of the nitrogen.
Cluster treatment facilities, for groups of homes, typically offer treatment to remove about 50% of the nitrogen, but can have nitrogen removal equipment added which will remove 75%.
Individual on-site treatment systems, as regulated by Boards of Health under Title 5, remove about 40% of the nitrogen through biological treatment.
Currently, wastewater from about 1,800 properties is treated in one of the Island’s five wastewater treatment plants (Edgartown, Oak Bluffs, Tisbury, Airport, and Wampanoag Tribal Housing), while over 14,000 Vineyard properties (more than 90%) treat wastewater on site — in cesspools, in older septic systems, or in newer Title 5 septic systems.
Town Boards of Health enforce Title 5, the State Sanitary Code, to ensure wastewater disposal by septic systems protects human health, although Title 5 is not focused on the impact to surface waters. Protective measures include system design, location, distance to groundwater, and separation from down-gradient wells. The amount of potential nitrogen entering the groundwater from wastewater disposal is only regulated when
Centralized treatment is quite costly to build and maintain. When the cost is calculated over the lifetime of the system — including construction, operation and maintenance — the cost is $20,000 per residence if an existing sewer and a treatment plant with available capacity are nearby, and $75,000 to $100,000 per residence if a new treatment facility and sewers must be built. However, if nitrogen reduction is necessary, the cost of individual on-site treatment could be equally high for two reasons: the systems are not very effective so about three houses would need these systems to offset the nitrogen from each house that is over the nitrogen-loading limit for its location, and because these systems have high operating and maintenance costs. It is a real dilemma for the Vineyard that, for a large part of the Island, the density is so low that individual, on-site wastewater systems may be the only possible treatment.
Wastewater regulations often serve to limit number of buildings, or at least the number of bedrooms, that can take place in certain areas. A major concern with improving wastewater treatment is that this could then open up these areas to additional development. Therefore, we must carefully consider the need for wastewater treatment to be “growth neutral” and for zoning regulations to ensure that inappropriate development does not take place.
The MVC works with towns to evaluate the need to expand or upgrade their sewage treatment systems. When reviewing proposed Developments of Regional Impact, the Commission also carefully examines the proposal’s wastewater disposal, especially with respect to the amount of nitrogen being put into nitrogen-sensitive watersheds.
The MVC hosted an Innovative/Alternative Conference on May 12,2016. The goal of this conference was to bring together industry professionals, scientists, policy makers and local stakeholders to discuss the issue of nutrient pollution in our local ponds and estuaries, and to explore various technologies and solutions to this problem. With the wide range of potential solutions discussed, we are confident that our community can prevent further degradation of water quality and take measures to improve the health of our ponds. The MVC will continue to host informational sessions on alternative solutions and we look forward to collaborating to help clean up our waters.Below are links to the presentations given at the conference and a link to MVTV to view the proceedings.
Morning Session link to MVTV site https://player.vimeo.com/video/166645486
- Michael Giggey, Cleaning up Our Waters
- Dr. Brian Howes, MEP Process and findings
- George Heufelder, Alternative Septic Test Center
Afternoon Session link to MVTV site https://player.vimeo.com/video/167652677
- Rob Zimmerman, Kohler CLASS
- Gary Rubenstein, Permeable Reactive Barriers
- Dave Thompson, Traditional Sewers
- Mike Moreau, FAST I/A Systems
- Rick Karney, Shellfish Aquaculture
- Mollie Caliri and Andrew McBrearty, Amphidrome
- Dave Grunden, Inlet Opening and Constructed Wetlands
- Michael Loberg, Tisbury Board of Health Regulations
MVC DRI Policy – Water Quality: Outlines the standards that the MVC uses to evaluate the proposed wastewater systems for Developments of Regional Impact.
Alternative Nitrogen Removal Options: As an alternative to traditional Title 5 septic systems and centralized wastewater treatment systems, there are a number of techniques that can be used to reduce nitrogen at the source or to mitigate its impacts on coastal ponds. This page (under construction) includes links to some of them.
Alternative Septic System Test Center: The test center, located in Sandwich, MA, evaluates the performance and operations costs of innovative alternative wastewater disposal technologies to provide economical alternatives to conventional septic systems.
National Small Flows Clearinghouse: Provides objective information and data to communities and individuals to help solve wastewater problems with onsite wastewater collection and treatment systems.