The historic Ashtabula Water Treatment Plant has been delivering high quality, reliable drinking water to its customers dating back to 1887. As the current plant was reaching its useful life, Aqua Ohio set out to perform a major upgrade of the facility while maintaining reliable service to its customers during the construction to this historical facility. Aqua Ohio’s overall goal was to optimize capital costs to achieve maximum improvements to its efficiency and effluent quality while maintaining long-term regulatory compliance.
Aqua Ohio partnered with The Great Lakes Construction Co. to design,
permit and oversee the construction of this major upgrade all within a 19-month time frame. To accomplish this aggressive schedule, Aqua Ohio utilized a Progressive Design-Build Delivery Method. This contract structure allowed Aqua Ohio to qualitatively select Great Lakes as its design-builder based on our industry leading technical experience and reputation of successfully completed water/wastewater treatment plants and other complex heavy civil projects. In addition, a detailed technical proposal, competitive fee structure and design partner selection were all considered in the selection process.
The process commenced on May 12, 2020, with the project kick-off meeting. To ensure that Aqua Ohio’s mission critical goals and deliverables were at the core of the fast-moving design, Great Lakes coordinated process innovation workshops with Aqua Ohio and our design partner, HDR at regular intervals.
Groundbreaking occurred on January 3, 2021, with the Great Lakes team initiating earthwork, structural concrete, and underground utility installation thru the winter months. Construction continued concurrently with detailed design, and one of the keys to the success of this Project was the use of regularly scheduled design coordination meetings to further progress the detailed design in order for construction to continue uninterrupted.
The scope of work includes two treatment process improvements. “Phase 1”, the rehabilitation and modernization of the plant’s existing filtration process with all new equipment and a new fully integrated automation/control system. “Phase 2”, the construction of a new 10 MGD Flocculation-Sedimentation Building with 3-stage flocculation, inclined plate settlers, and instrumentation and controls for an automated system. The aggressive schedule facilitated the need to proactively construct both phases concurrently, to ensure the December 2021 plant startup was in the forefront of planning.
This Project represents the first installation of inclined plate settlers at any municipal water treatment plant in the State of Ohio. Raw water from Lake Erie will enter the new 7,200 SF Flocculation-Sedimentation Facility through a splitter box at the head of the process and channel flow into one of two floc-sed process trains – each with a rapid mix chamber, three stages of flocculation, and ultimately thru the plate settlers. These state-of-the-art plate settlers will yield significantly reduced detention time of at least half the time compared to traditional settling. This reduced detention time yielded a significantly smaller settling basin than a traditional settling basin would have been, and maintains full permitted capacity.
At the tail end of the floc-sed process, flow exits through effluent troughs into new underground piping to an upgraded Filtration Facility, which underwent a major retrofit from its original structure, built in 1908.
One of the challenges the team had to overcome was working within the constraints of the century old facility and its many structural hurdles. The team has installed a complex ductile iron piping network and 48 EA motor actuated valves, all within a tightly constrained below grade pipe gallery. Another challenge was detailing and fabricating the new custom-built FPR backwash troughs to precisely align and connect with the portions of the existing FRP backwash trough system that remained in place.
This Project highlights Great Lakes’ ability to be adaptable to an ever-changing design plan; forecast upcoming material needs in an economy and supply-chain hampered by COVID-19; and overcome adverse construction conditions of a plant that rests only 4LF above Lake Erie water elevation.
The project is on track for a successful commissioning phase in December 2021 allowing Aqua Ohio to start the new year with a state-of-the-art facility that will serve its customers for decades to come.