Henderson, Kentucky

Henderson, Kentucky

Project Description: The Henderson Water Utility (HWU) operates a combined sewer system which discharges to the Ohio River. On August 7, 2007, HWU entered into a Consent Judgment with regulators with the primary objective being to reduce the discharge of combined sewer to the environment. HWU’s Long Term Control Plan included multiple complex projects which have allowed the utility to meet this objective. Recent improvements to the Henderson Water Utility’s North Wastewater Treatment Plant (WWTP) have increased the peak hydraulic capacity of the WWTP from 15.0 MGD to 25.5 MGD. These improvements included a new headworks, renovation of one aeration basin, one new 160’ diameter final clarifier, reuse of two existing 140’ diameter final clarifiers, new RAS Pumping Station, and new Ultraviolet (UV) Disinfection Facility. In addition to the projects at the WWTP site, two major pumping station and force main upgrades were required in order to deliver the peak flow rate. Design of this 25.5 MGD project included provisions allowing the WWTP hydraulic capacity to be increased to 36.0 MGD with the installation of additional equipment and one additional 160’ diameter final clarifier. With completion of the North Wastewater Treatment Plant Improvements, HWU has finished all major projects under its Long-Term Control Plan, which required an investment of approximately $55 million.

Project Name: North Wastewater Treatment Plant Improvements Long-Term Control Plan

Utility Name and Location: Henderson Water Utility, Henderson, Kentucky

Key Personnel: J. Gregory Davenport, P.E., Stephen C. Lee, P.E. Robert S. Qualman, Jr., P.E., Dwight Phillips, Electrical Engineering

Construction Cost: Approximately $55 million

Date of Completion: n/a

Engineering Services: Planning, Detailed Design, Bidding and Award, Construction Administration, and Resident Observation

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The project included the installation on one stacked tray type grit removal mechanism (pictured above). The capacity of the headworks can be expanded to 36.0 MGD by adding one (1) additional 18.0 MGD stacked tray type grit removal mechanism.

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Improvements to one aeration basin included removal of the existing coarse bubble aeration system and installation of 7,500 9-inch diameter fine bubble diffusers (pictured left). The existing liner system was replaced with a reinforced concrete slab to allow mounting of the diffusers and new 60 mil synthetic liner on the side slopes. Replacement of the influent and effluent piping increased the hydraulic capacity through the basin and prevented short circuiting. Future plans include similar improvements to the two remaining aeration basins at the WWTP.

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One (1) new 160’ diameter final clarifier (pictured right) works in conjunction with two (2) existing 140’ diameter clarifiers resulting in a peak hydraulic capacity of 25.5 MGD. The hydraulic capacity of the clarification can be expanded to 36.0 MGD by adding one (1) 160’ diameter clarifier. The piping and control system allow for automatic transition of the clarifiers from series clarification under average flow conditions to parallel clarification under peak flow conditions.

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The new UV Disinfection Facility (pictured left) has a peak hydraulic capacity of 36.0 MGD at a UV transmittance of 50%. Effluent reuse pumps housed in this building deliver pressurized effluent to various plant processes throughout the facility in lieu of using potable water.

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Improvements were necessary to increase the hydraulic capacity of the main sewage pumping stations which discharge the WWTP. Construction of the new 22.0 MGD North Fork Sewage Pumping Station (SPS) included the installation of four (4) 315 horse power submersible pumps (pictured right). Other improvements required in the collection system included renovation of the 12.0 MGD Janalee Drive SPS, and new 24-inch and 30-inch influent force mains between these SPSs and the WWTP. At the present time, the North Fork SPS is programmed to operate at reduced capacity of 12.0 MGD resulting in a maximum flow rate of 25.5 to the WWTP, including 12.0 MGD from Janalee Drive SPS, and 1.5 MGD from other small pumping stations. In the future, 36.0 MGD can be pumped to the WWTP including 22.0 MGD from North Fork SPS, 12.0 MGD from Janalee Drive SPS, and 2.0 MGD from other Pumping Stations.