Clinton, IN

CSO Long-Term Control Plan (LTCP) Phases 1 & 2

HWC completed an updated CSO Long-Term Control Plan (LTCP) for the City of Clinton’s combined sewer system. 

The study included mapping and evaluation of the City’s combined sanitary and storm sewer system, evaluation of the City’s wastewater treatment facility capacity, coordination of flow monitoring, development of a combined sewer system SWMM model for use in analysis of alternatives, evaluation of alternatives, and preparation and presentation of the report. 

The plan, which was required by the City’s NPDES permit, recommended improvements to control the volume and frequency of combined sewer overflows in the City’s system. The plan was approved by IDEM in December 2011. A State Revolving Fund (SRF) Preliminary Engineering Report (PER) was prepared in 2013 for Phase I work. 

HWC is completing engineering design and management of all LTCP recommended improvements. 

Phase 1, which consisted of floatable control screening, wastewater treatment facility headworks modifications, combined sewer separation via new storm sewers and outfall consolidation, was completed in 2016. 

The plan is based on a 20-year implementation schedule and will reduce the six existing overflows to three. Multiple areas of combined sewer separation are planned via installation of new storm sewers. Based on SWMM model results and financial analysis, the $10.5 million plan will require a Use Attainability Analysis (UAA) at the conclusion of implementation based on use of the presumptive approach for CSO control.

Jasonville, IN

Shakamak State Park Regionalization and Wastewater System Improvements

HWC completed a Preliminary Engineering Report (PER) for funding through the Indiana Finance Authority (IFA)’s State Revolving Fund (SRF) Program for this project. The PER was prepared to address several needs, including:

• Significant inflow and infiltration in the Shakamak State Park collection system
• Aging and deteriorating equipment and controls at the Shakamak Wastewater Treatment Facility (WWTF)
• Alleviating IDNR from having to operate a wastewater treatment facility
• Addressing the hydraulic capacity issues and difficulty meeting ammonia limits at Jasonville’s existing WWTF

To address the needs discussed above, the recommended project in the PER included the Shakamak State Park collection system rehabilitation, wastewater conveyance infrastructure from Shakamak State Park to the City of Jasonville’s WWTF, and upgrades to Jasonville’s existing WWTF. The Shakamak State Park collection system improvements included gravity sewer rehabilitation, consisting of lining approximately 3,745 LF of gravity sewer mains via cured-in-place pipe (CIPP), along with other miscellaneous repairs and upgrades to the park’s collection system. The wastewater conveyance improvements included upgrading Shakamak’s existing Lift Station Number Five with new pumps and installing approximately three miles of force main from the lift station to Jasonville’s WWTF for treatment of park flows along with decommissioning Shakamak’s existing WWTF. The improvements to Jasonville’s WWTF included the removal of the lagoon cover system, installation of a new submerged attached growth reactor (SAGR) treatment system, and additional flow equalization storage volume.

The project was completed in January of 2025 with a construction cost of $8.37 million.

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.

Veedersburg, IN

Build-Operate-Transfer (BOT) Wastewater System Improvements

The Veedersburg Wastewater System Improvements project included improvements to the existing Wastewater Treatment Plant (WWTP) to improve overall efficiency of the treatment system and update critical pieces of equipment. The project included replacement of the antiquated aerated lagoon “biolac” treatment system with a new oxidation ditch and two secondary clarifiers, a new influent structure, replacement of the existing UV treatment system with a non-contact type UV system, post-aeration, conversion of the existing north clarifier to a digester, and various improvements to electrical and controls. In addition, the project included the replacement of five lift stations (Primary, Sherman Street, Main Street, College Street, and Viewer Hills) located throughout the Town of Veedersburg to replace deteriorated facilities and improve the operation and efficiency of the collection system.  The project utilized the Build-Operate-Transfer (BOT) delivery method and was funded in part by the State Revolving Fund (SRF) program.

The $9.5 million project was completed in the fall of 2023.

Attica, IN

CSO LTCP Phase 2/Wastewater Treatment Facility Renovation

HWC worked with Attica, Indiana to complete Phase 2 of the City’s mandated CSO LTCP project. 

The City’s CSO Long-Term Control Plan required a second and final phase, which included floatables screening of flows from the single remaining overflow outfall to remain operational and storage of approximately 750,000 gallons of combined sewer flows to meet IDEM’s design storm criteria. HWC was hired to develop a Preliminary Engineering Report for the CSO project and necessary improvements at the treatment facility to address depreciation and compliance needs. 

The plan developed included improvements at the treatment facility, including:

• New influent/CSO screening structure, which complied with the floatables control requirement of the CSO LTCP and fine screening for all influent flows
• New 750,000 gallon per day average flow/1.2 MGD peak flow oxidation ditch for biological treatment to replace the current trickling filter process
• Conversion of existing primary clarifiers to secondary clarifiers
• Conversion of the existing trickling filter tanks to CSO storage tanks, which will be filled by dedicated CSO pumps in the retrofitted influent wet well
• Chemical feed systems and piping for nutrient (phosphorus) control
• Implementation of a new plant-wide SCADA system for both biological and wet weather process control

Due to the re-utilization of existing structures and conversion to a new biological treatment process, significant construction sequencing considerations were required in the design of the project. HWC held working sessions with the plant staff during design and with both the contractor and staff during construction to ensure minimization of operational disruptions were realized through demolition and sequencing of construction activities.

The total project cost was approximately $5.5 million. HWC provided planning, design, construction engineering, and inspection services for the project.