"The Vital Back Cove Ecosystem will be Protected from Pollution for Future Generations to Come.”
STATE STREET INFRASTRUCTURE IMPROVEMENT PROJECT
The City of Portland, Maine is known for its booming arts and culture scene, historical seaport and famous seaside beauty. But for years now the residents and wildlife of Portland have faced a commonly reoccurring problem. Heavy rainfall events have led to a tremendous undertaking by the combined sewer to transport rainwater and sewage to the East End Wastewater Treatment Plant, ultimately failing. The combination of sewage and stormwater overwhelms the system and discharges into the nearby Back Cove estuary basin. This chronic issue has garnered increased concern from city officials for the health and well being of Portland residents, wildlife and the Back Cove ecosystem.
Therefore, the City of Portland commissioned a contract with engineering firm Gorrill Palmer and general contractor Sargent Corporation to separate the combined sewer system into a dedicated sanitary sewer and storm drain along State Street. Included in the project plans were a new storm drain outfall at Back Cove, permeable paving and the installation of a Nutrient Separating Baffle Box® (NSBB) hydrodynamic separator at Deering Oaks Park. The State Street Infrastructure Project ensures water quality improvement by minimizing combined sewer overflows (CSO) and taking preventative measures via the NSBB to filter rainwater flowing into Back Cove. Overall, upon completion, human and wildlife health will improve drastically and the vital Back Cove ecosystem will be protected from non point source stormwater pollution for years to come.
Ground was struck near the Interstate 295 overpass on July, 5 2017 as the city contractor, Sargent Corporation, began the installation of a new 84” storm drain outfall into Back Cove estuary. Crews at Preble Street Ext. worked tirelessly while a second crew simultaneously began building a new sewer and storm drain along State Street from Forrest Ave to Park Ave. On August, 10 2017 work began along State St from Park Ave to Deering St in which new storm drain, sewer pipe, water main, gas main and ADA ramps are being installed. The separation of the sewer and storm drain eliminates 100 acres of drainage area which include flows that enter Deering Oaks Park Pond from the combined sewer shed impacting Back Cove.
State Street NSBB™ Powers Pollution Prevention
Direct treatment of the stormwater flowing from Deering Oaks is now filtered via an NSBB which was installed on October, 11 2017. The NSBB, developed by Suntree Technologies Inc®, an Oldcastle Infrastructure™ company, is a hydrodynamic separator specializing in online sediment capture without the typical associated headloss and sediment scouring. It’s patented lidded screens prevent nutrient leaching and static water from turning septic from trash and debris. It also includes a floating skimmer unit to prevent debris from passing through the vault during high flows and a StormBoom™ that absorbs hydrocarbons via an absorption media.
Prior to delivery, Suntree Technologies Inc personnel were on site at a local precast facility to install the NSBB internal components including the deflectors and
HydroSlide® platform. The HydroSlide is an optional servicing system for the NSBB to facilitate sediment removal. The system reduces servicing time by using a vacuum truck to spray water through its pipes loosening sediment and easily vacuuming it away. The system does not require confined space entry, effectively saving the city a great deal in upkeep costs. The delivery and installation of the vault structure went off without a hitch taking only a day to complete as a joint effort between the Sargent Corporation, Gorrill Palmer, and Suntree Technologies. The State Street NSBB vastly improves the water quality of runoff flowing from Deering Oaks Park and prevents the pollution of Back Cove with trash, sediment and hydrocarbons. The City’s investment in water quality will ensure a decline in stormwater pollution and increase in better community health.
© 2018 Suntree Technologies Inc