Big Decisions: Repair or Build New to Meet Increased Utility Demands?

Big Decisions: Repair or Build New to Meet Increased Utility Demands?

As cities and towns grow, both residentially and commercially, they often struggle to meet increased demands for utility services. This is frequently the case with wastewater treatment. Many municipal treatment facilities were built during a period of abundant direct state and federal grant program assistance in the 1970s, and much of that infrastructure is nearing the end of its lifecycle. Municipalities are faced with the choice to implement repairs or to build new infrastructure. The choice to do nothing is often not a real option. Plus, federal and state regulations are only becoming more stringent, which puts added pressure on operators to improve their treatment systems.

The City of Ellsworth faced exactly this dilemma. It is the service center for the Downeast region of Maine and is one of Maine’s fastest growing cities. Its existing wastewater treatment facility (WWTF), located in the middle of the downtown waterfront area and built in 1978, was operating at its maximum licensed capacity of .85 MGD. Its outdated technology and equipment required repair and replacement. During wet weather events, inflow and infiltration in the collection system caused overflows to the Union River and resulted in negative environmental impacts.

The City worked with Woodard & Curran to assess its options, which included upgrades at the existing site or building a new facility at an off-site location. Ellsworth decided to build a new treatment facility at a new location that provided adequate buffer from nearby land owners and sufficient space for each unit process. A new pump station was also designed and built at the old WWTF site to take advantage of the existing collection system infrastructure while freeing up space to further develop the waterfront area. The former WWTF is currently being demolished and plans are underway to restore the site.

We worked with Ellsworth through the project planning, funding, design, permitting, construction, startup, and acclimation process, and we continue to assist Ellsworth’s staff with the ongoing operational support phases of the project.

The City secured $20 million of funding through a combination of Community Development Block Grants, Rural Development grants and loans, State of Maine grants and loans, and federal earmarks. Energy efficiency, high effluent quality, ease of operation, and flexibility in process control to accommodate current and future needs were key considerations in the design of the new 1.65 MGD WWTF. Some of the state-of-the-art systems include high-efficiency centrifugal turbo blowers that deliver low-pressure process air to the biological reactor and an effluent-source heat pump system specifically designed to use treated wastewater (chlorinated effluent) as a source/sink of energy for heating and cooling of the facility buildings.

These cost-saving features at the WWTF demonstrate the value of Ellsworth’s decision to invest in a new facility and provide sustainable utility service for the City.

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Project Engineer
Municipal Wastewater

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