New Albany, IN

Wet Weather Clarifier System Improvements

HWC worked with the City of New Albany, Indiana to complete their Wet Weather Clarifier System Improvements project.

The City of New Albany operates a 30 MGD treatment facility with discharge to the Ohio River. Due to excessive wet weather flows from the separate sanitary sewer system, flow rates up to 75 MGD are conveyed to the treatment facility. A passive overflow structure downstream of three oxidation ditches allows flows of up to 30 MGD to be conveyed to secondary clarifiers while excess flows are diverted to the wet weather clarifiers with an overall capacity of 48 MGD. There are six wet weather clarifiers with circular clarifier mechanisms in square concrete tanks along with all associated piping and equipment. The condition of the clarifiers had depreciated along with the RAS/WAS pumping systems and disinfection facilities for the wet weather flow train, such that the City desired to develop a plan to rehabilitate the wet weather clarification systems.

HWC was retained to develop a basis of design study for the wet weather processes and equipment for developing a final scope of work and budget for the proposed project. The resulting plan evaluated several different alternatives, including complete replacement of all systems with various clarifier tank layouts.

Based on budgetary considerations and the frequency of use of the wet weather clarification system, the selected plan included rehabilitation of the existing systems and equipment. The total project cost was approximately $1.75 million with construction completed in 2019. HWC provided planning, design, bidding, and construction engineering/inspection services for the project.

HWC’s Project Manager was Jon Query, PE.