Dayton, Ohio. 45402
Organization Contact Details
In 2016, the Environmental Protection Agency (EPA) introduced lower Health Advisory Levels (HAL) for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) at 70 ppts. The City had previously monitored for PFOA and PFOS during the Third Unregulated Contaminant Monitoring Rule (UCMR3) 2013-1015, with the results showing as non-detect at Ottawa and Miami Water Treatment Plant, as the detection limits were 20 and 40ppt respectively.
Upstream of the City’s water source Wright Patterson Airforce Base (WPAFB) detected PFAS during UCMR3 above the HAL. Under the advisement of the regulatory agency and out of an abundance of caution, the City took aggressive actions to preserve the source water and ensure its customers receive safe, high-quality drinking water. Measures included:
• Expanding the early warning monitoring well network.
• Monitoring at the treatment plants.
• Removing production wells from operational rotation.
The removal of production wells from operational rotation was viewed as a temporary solution while the City investigated more sustainable solutions, using the data gained from the increased monitoring schedules. Also, removing production wells decreased the water systems redundancy and increased operational costs as production wells are not rotated on their normal schedules.
In 2018, an updated analytical method was approved, lowering the quantifiable concentration numbers of PFOA and PFOS. Thus, the City started seeing detections in its Mad River Well Field and its Ottawa Water Treatment. The Mad River Well Field supplies water to the Ottawa Water Treatment Plant and the Miami Well Field supplies water to the Miami Water Treatment Plant. Currently, the water supplies are separate.
In June 2022, the EPA again lowered HAL for perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and introduced new HALS perfluorobutanesulfonic acid (PFBS), and GenX. The current City detections:
• PFOA 4 ppq (0.004ppt)
o Ottawa Water Treatment Plant 1.20 ppt (5/10/22)- 5.14 ppt (12/14/19)
o Miami Water Treatment Plant ND
• PFOS 20ppq (0.020ppt)
o Ottawa Water Treatment Plant 1.20 ppt (6/26/19)- 13.7 ppt (9/06/18)
o Miami Water Treatment Plant ND
• GenX 10ppt
o ND at Ottawa and Miami Water Treatment Points
• PFBS 2000 ppt
o ND at Ottawa and Miami Water Treatment Points
As previously stated, the City took temporary aggressive actions of removing production wells from operational rotation while waiting on the final guidance agency and developing a more permanent solution to manage PFAS contamination found in its water, based on data gathered from 2015 through the present.
SCOPE OF PROJECT
2.01 PURPOSE AND NEED / PROJECT DESCRIPTION. The City of Dayton, Department of Water (Dayton Water) is seeking proposals from a highly experienced and professional engineering Consultant to design an expansion of the Miami Well Field South’s recharge system. The work shall include the design of network of channels to support the installation of seven additional productions wells. Design will include a new pump station to transport the river water to the channel network and piping from the pump station to the channels. Design will also include a system to monitor infiltration rate. The final layout of new production wells and a recharge channel network may be completed through several construction projects over time.
2.02 BACKGROUND INFORMATION.
Dayton Water owns and operates two well fields, Mad River and Miami, and two water treatment plants, Ottawa and Miami. The Miami Well Field is located in and around the former Kitty Hawk Golf Course. The Miami Treatment Plan is located at the southeast corner of the former golf course. The Mad River Well Field extends along the Mad River from northeast of North Irwin Street northeast to southwest of the Huffman Dam. As part of its PFAS strategy, Dayton Water will expand the capacity of the Miami Well Field with the installation of additional wells and a network of channels to help support healthy water levels in the aquifer. This project is a critical component of the PFAS strategy.
2.03 SCOPE OF WORK / PROJECT REQUIREMENTS.
The Consultant shall outline a proposed technical project approach, including specific tasks required to execute the project. The Proposal shall include the Consultant’s qualifications, experience, and approach to the project. It is anticipated the design of the lagoon network will take seven months and contraction drawings to construction contract award will take five months. The construction schedule is to be determined during the design process.
Task A – Project Management and Coordination
Communication with Dayton Water and Montgomery County throughout the project is imperative. A kick-off meeting, progress meetings/calls, and design review meetings with Dayton Water are required.
Task B – Lagoon Network and Piping Design
The Consultant shall review and identify all relevant information for work within the project scope. Dayton Water will provide all available information including as-builts (if available), existing maintenance work order history for the exiting recharge system, GIS, and existing survey information. From the information gathered and through discussions with Water Department staff a final layout of channel network and final production wells shall be designed.
1. Design a final layout of eight production wells, in accordance with the preliminary study and OEPA requirements. Design piping network to convey pumped raw water to the Miami Treatment Plant.
2. Design a final layout of the channel network, including final elevations. The lagoon network will need to be taken to of service, in sections at a time, to allow for maintenance.
3. Design a layout network of piping to transport river water to the recharge channels.
4. Design of the piping network to the recharge channels shall allow for the ability to take down sections at a time for maintenance.
5. Design a new pump station to pump water from the south end of the settling basin to the lagoon network, allowing for redundancy and maintenance.
6. Channel design, piping network and pump station shall work with the existing recharge system.
Task C – Projects Survey and Construction Drawings
Consultant shall take phase one of the fully designed project forward with construction plans and specifications. Plans shall be in accordance with City of Dayton construction standards and OEPA permit to install criteria.
Construction Plan Phase:
1. The Consultant shall perform a full topographic survey and basemapping.
2. Provide 30% and 60% construction drawings and specifications for Owner’s review. Design shall conform to all applicable Codes and Standards. Include a opinion of probable cost.
3. Provide Final construction plans. Drawings shall be stamped by a Registered Ohio Professional Engineer.
4. Provide construction cost estimates for all improvements.
5. Provide final drawings in AutoCAD format, and specifications in Word format.
6. Prepare written responses to any technical questions received from prospective bidders.
7. If required, prepare addenda to clarify, correct or change the contract documents.
8. Attend the pre-bid meeting and contractor site visit.
9. Assist in the evaluation of bids and make a recommendation concerning award of the contract.
Construction Services Phase:
10. Review all submittals for approval based on conformance to Contract Documents. Submittals include schedule, shop drawings, and shop drawing resubmittals.
11. Attend Pre-construction meeting. Provide items for agenda in advance of meeting, including technical and schedule issues. Record meeting notes.
12. As work progresses and actual extent of defects becomes apparent, determine type and extent of repair work to be performed in specific areas, with Owner’s consent.
13. Evaluate all field change and change order claims.
14. Upon completion of construction, provide Owner with Construction Record Drawings in AutoCAD format and daily report logs in electronic format.