PIQUA — The city held a worksession Thursday evening to discuss the Wastewater Treatment Plant upgrades and expansion project due to the completion of the design phase and the upcoming construction phase. Commissioners John Martin and Joe Wilson attended the worksession.
The construction cost is estimated to be between mid-$30 million and mid-$40 million. The actual cost will be known when the construction bid documents are accepted, which will take place in June.
CDM Smith, the city’s design engineer for this project, completed the design after two years of working on it. Project Manager Mark George of CDM Smith gave the city an overview of the project during the worksession.
“We have an Ohio EPA mandate to deal with,” George said. “That mandate is related to the elimination of sanitary sewer overflow.”
The upgrades and expansion to the plant are necessary to address a mandate from the Ohio Environmental Protection Agency (EPA) to eliminate sanitary sewer overflow (SSO) within the city, which is wastewater that overflows into the Great Miami River without being treated.
The improvement project will also increase the plant’s capacity to treat wet-weather flow without sewer back-ups and treatment tank overflows. George also said that the improvements will be able to accommodate future commercial/industrial and residential growth, including up to 20-year growth projections. The project will also replace existing aging and worn-out treatment components and structures.
The plant was originally built over 60 years ago in 1956. The last major expansion done to the structure was in 1991.
The city has been planning improvements to the plant since 2004 after completing an SSO Study and Interceptor Sewer Model. In June 2006, the Ohio EPA required an SSO Elimination Plan and Compliance Schedule. Between 2007-2010, the city built and EQ basin for the plant, which the Ohio EPA required. A master plan for the project was completed in 2012 with an amended facility plan completed in 2014.
The Ohio EPA is expected to approve CDM Smith’s design for the project and issue a permit for the project by the middle of this month.
George explained the treatment processes included in the design are cost-effective, reliable, and operationally efficient. It will also provide flexibility to meet current and potential future regulatory requirements.
“We are utilizing existing Wastewater Treatment Plant facilities where it is cost-effective to do so,” George said, adding that the plant will be able to treat wastewater and biosolids effectively.
Components to the project include the addition of oxidation ditches.
“These ditches provide biological treatment,” George said.
George explained how they are efficient biological removal of organics from incoming wastewater. George also noted how an Ohio EPA review engineer commended the inclusion of this in the design. The city will also be able to apply for a zero percent interest loan from the Ohio EPA for aspects of the project related to biological nutrient removal.
The project also includes building three clarifiers, each one being 120 feet in diameter and approximately 16 feet deep. The clarifiers will remove treated solids from a liquid stream. The plant’s current clarifiers are approximately 55 feet in diameter and 10 feet deep.
Another notable component to the project is that the plant’s existing chlorine contact tank will also be retrofitted with an ultra-violet (UV) disinfection system, which George said is an updated, safer, and more effective disinfection technology.
Other upgrades and repairs are also included in the project.
The construction period for the project is expected to last 38 months — or around three years and two months — but the Ohio EPA’s deadline for the city to eliminate SSO is in February 2020, or approximately 31 months away. George said that it will be in the construction company’s contract to complete the infrastructure that will eliminate SSO by the February 2020 deadline.
CDM Smith already held a pre-bid meeting with construction companies, which was mandatory for companies to attend if they want to submit a bid for the project. George said that six major companies attended the meeting and that all of them are reputable businesses that have previously worked with CDM Smith.
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