Transforming Wastewater Treatment for a Growing City
Our team of professional engineers and scientists are assisting the City of Saco, ME with the alternatives analysis, design, permitting, and construction of a comprehensive set of upgrades to improve the resiliency and treatment capacity of the City’s Water Resource Recovery Facility (WRRF). Currently in construction, the completed upgrades will safeguard the treatment plant against flooding and sea level rise, while also increasing its capacity to treat wastewater and improving the treatment process.
Since the WRRF was originally constructed in the 1970s, Saco’s population has increased consistently and is projected to continue to grow over the next several decades. The upgrades to the WRRF will raise the plant’s daily treatment capacity from 4.2 million gallons per day (MGD) to 8 MGD, ensuring the system will have the capacity to accommodate future growth for several decades.
This $62 million project is being funded by a Clean Water State Revolving Fund (CWSRF) Loan and Grant through the MaineDEP and Congressionally Directed Spending (CDS) grants through the EPA. Our firm partnered with EPA to undertake an Augmented Alternatives Analysis (AAA), following an EPA framework that engaged stakeholders to compare solutions and determine the best path forward for the community. As part of the social equity component of the project, various public amenities were incorporated into the site, including new green space, public restrooms, and boat launch improvements.
A portion of the WRRF is located within a FEMA-designated 100-year flood zone, and in recent years, extreme high tides and coincident storm events have inundated the plant and disrupted the treatment process and gravity flow through the facility. The major upgrades will raise the treatment process facility’s elevation and relocate critical electrical assets to improve resiliency and address sea level rise impacts.
The facility will use an innovative Aerobic Granular Sludge (AGS) process to improve the quality of treated wastewater. The AGS process allows for secondary treatment and nutrient removal within the constraints of the WRRF site. Our engineers worked with the City of Saco and AquaNereda to design a wastewater treatment process that allows for optimal treatment performance while minimizing cost. Other process improvements include new systems for headworks screening and grit removal, influent pumping, tertiary filtration, ultraviolet (UV) light disinfection, solids handling, and a full electrical upgrade.
We worked closely with the MaineDEP, the City of Saco, and the Saco River Corridor Commission to obtain the necessary permitting approvals for the site, stormwater, and flood resiliency upgrades for the Saco WRRF. The project is being implemented through a Construction Manager at Risk (CMAR) form of collaborative project delivery. Tighe & Bond is serving as both the Owner’s Agent and Design Engineer.
Services Snapshot
Tighe & Bond assisted the City of Saco with design, permitting, grant assistance, and construction phase services in support of this project. Our work included the design of a comprehensive set of site upgrades to improve process and resiliency, site surveying using a 3D scanner, hazardous building material assessments (HBMA), and geotechnical engineering services.
