Explanation
1. Background:
This legislation authorizes the Director of Public Utilities to enter into an engineering modification agreement (Mod#1) with ARCADIS U.S. Inc., for the Wastewater Treatment Facilities Ash Lagoons Improvements. This professional services contract modification with ARCADIS U.S., Inc. will provide continuing professional engineering services for the Wastewater Treatment Facilities Ash Lagoons Improvements project, Project 650333-100000. Both the Jackson Pike (JPWWTP) and Southerly Wastewater Treatment Plants (SWWTP) have two biosolids multiple hearth incinerators. The ash produced is mixed with incinerator scrubber water and/or plant flushing water and was previously pumped to the two ash lagoons at each plant. There was a concern that decant draining off the ash lagoons would not meet the new copper limits of the NPDES permits at both plants. The Scope of Work for this project, at the City’s discretion, originally consisted of the following elements:
A. This project was originally intended to investigate the construction of new ash lagoons that were to drain to the plant effluent for the purpose of diluting the copper concentrations of the ash decant to acceptable concentrations for release into the Scioto River, or to combine the existing ash lagoon decant with the treatment plants’ effluents, or to recycle decant from the existing ash lagoons to plants’ headworks for treatment.
B. Jackson Pike WWTP:
1. Study the structure of the Jackson Pike ash lagoons and investigate options to replace them or to provide new ash lagoon liners for both lagoons and construct a new ash flume or alternative ash conveyance system.
C. Southerly WWTP:
1. Investigate new, smaller ash storage and conveyance to be constructed out of the Scioto River floodway, due to floodway constraints.
However, a Business Case Evaluation (BCE) was performed. Early in the BCE process, an alternative to the originally-envisioned ash lagoon modifications or new lagoon ...
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