Wastewater > Project Case Study

Wastewater Management Planning and
Decentralized Systems

Cape Cod Commission, Massachusetts
Cape Cod's 15 towns – from Bourne to Provincetown – span 86 coastal watersheds. With the technical assistance of Wright-Pierce, the Cape Cod Commission is documenting the population and wastewater flows in those coastal watersheds that contribute nitrogen to poorly flushed embayments. Total Maximum Daily Loads (TMDLs) have been established for many of those embayments through the Massachusetts Estuaries Project. It is expected that nearly 40% of the Cape's wastewater will eventually be subject to stringent nitrogen control requirements. Wright-Pierce is helping the Commission determine where decentralized and centralized solutions are most appropriate and preparing a Cape-wide estimate of likely costs for collection, treatment and disposal.

The Pinehills, Plymouth Massachusetts
Wright-Pierce was part of a consulting team that guided the planning, design and construction of wastewater facilities for this major residential and commercial development in Plymouth Massachusetts. Design documents for the 150,000-gallon-per-day wastewater treatment facility for Phase 1 were prepared in 1999 and 2000 and the $6 million project was completed in 2001. Following advanced treatment, the plant effluent recharges the groundwater through rapid infiltration basins. Some of the effluent-impacted groundwater is recovered  in capture wells down-gradient from the recharge facility and used for irrigation of the project's golf course.

Tisbury, Massachusetts
This Martha's Vineyard community built a municipal wastewater system in 2003 that consists of an advanced treatment facility and two subsurface leaching areas. With recent concern over nitrogen loading to two coastal ponds, the Town hired Wright-Pierce to conduct groundwater modeling to better define the watersheds of those coastal ponds and to determine if one or both of the wastewater disposal areas may be contributing nitrogen to those sensitive watersheds. Wright-Pierce has identified several alternative disposal sites and is investigating effluent reuse opportunities. The current facilities are permitted for 104,000 gallons per day.

Milbridge, Maine
The downeast Maine town of Milbridge has operated its wastewater facilities under a 301(h) waiver from EPA that has allowed primary treatment and chlorination prior to discharge through an outfall to coastal waters.  When that waiver was revoked, Milbridge hired Wright-Pierce to design three modular secondary treatment plants for the largest commercial users in town, upgrade the central disinfection facility and suggest improvements to the 67 septic-tank-and-sand-filter systems. This combination of decentralized and centralized facilities is a cost-effective solution for the 100 properties served by this small town.   

Martha's Vineyard Commission, Massachusetts
Martha's Vineyard is famous for its beautiful beaches and coastal ponds. The Martha's Vineyard Commission has undertaken a regional wastewater planning study to determine the nature and extent of facilities that may be needed to preserve the water quality that is central to the Island's environment. Wright-Pierce has provided technical assistance to the Commission by evaluating a series of case studies to determine the most appropriate wastewater systems for a range of circumstances. One cost-effective solution may involve eliminating septic systems in nitrogen-sensitive watersheds by sewering densely developed areas to the three existing municipal wastewater facilities on the island, coupled with some decentralized systems for the remainder of the island. Wright-Pierce has also identified many "non-structural" options to address other sources of nitrogen, managing future growth, and equitable sharing of costs.