Sixth Street Water Treatment Plant Sodium Hypochlorite Generation System Replacement

Key Accomplishments

Johnston Construction Company

• Johnston Construction Company performed design-build construction services for the VWPA Sixth St. WTP Hypo Generation Project in Susquehanna Township, Dauphin County, Pennsylvania.
• The project included design and installation of a new on-site sodium hypochlorite generation system and removal of the existing obsolete on-site hypo generation system at Veolia Water Pennsylvania’s Sixth Street Water Treatment Plant.
• JCC contracted directly with Veolia Water Pennsylvania, Inc. under Task Order Agreement No. 16265, with Johnston Construction Company identified as the Contractor.
• The Sixth Street Water Treatment Plant is a 12 MGD water treatment facility consisting of pretreatment, filtration, and disinfection processes, serving customers across portions of Dauphin, Perry, and Cumberland Counties.
• The project included replacement of the obsolete ClorTec Model CT-200 backup hypo generation system with a new ClorTec Model CT-300 on-site sodium hypochlorite generation system.
• Major work included survey, design, permitting assistance, procurement, demolition, installation of the new hypo generation system, chemical transfer pumps, piping, electrical work, instrumentation, SCADA coordination, HVAC improvements, metal platform connection, doors, startup, commissioning, operator training, as-built drawings, O&M manuals, and closeout.
• The work required coordination with Veolia Water Pennsylvania, PA DEP, the JCC design-build team, IC&EE, Electrical Services Division, De Nora / ClorTec, Chesapeake Environmental, HIPCO, Brock Solutions, plant operations personnel, equipment vendors, and project stakeholders.
• The project required compliance with State and Federal Safe Drinking Water Act standards, Veolia standards, OSHA safety requirements, PA DEP Public Water Supply permitting requirements, building and trade permit requirements, electrical requirements, SCADA integration requirements, equipment startup requirements, training requirements, and final closeout requirements.
• Johnston Construction Company performed design-build construction services for the VWPA Sixth St. WTP Hypo Generation Project at Veolia Water Pennsylvania’s Sixth Street Water Treatment Plant, located at 4405 North 6th Street, Harrisburg, Pennsylvania.
• The project was required because the existing on-site sodium hypochlorite generation system was at the end of its useful life, and operation and maintenance had become difficult. Veolia required a new updated on-site generation system using current technology to improve reliability and efficiency.
• The Sixth Street Water Treatment Plant is rated for 12 MGD and includes pretreatment, filtration, and disinfection processes. The plant serves customers in Dauphin, Highspire, Hummelstown, Lower Paxton, Middle Paxton, Paxtang, Pennbrook, Swatara, Marysville, and portions of other surrounding communities in Dauphin, Perry, and Cumberland Counties.
• JCC’s design-build scope included designing, permitting, constructing, troubleshooting, inspecting, starting up, and commissioning the new on-site sodium hypochlorite generation system, along with removal of the existing obsolete 1998 on-site hypo generation system.
• Johnston Construction Company and Instrumentation, Control & Energy Engineering, LLC served as the integrated design-build team. JCC provided design-build construction leadership, project management, field supervision, procurement, subcontractor coordination, construction, startup coordination, operator training, as-built documentation, and closeout support.
• The new system included a De Nora Water Technologies ClorTec Model CT-300 on-site sodium hypochlorite generation system. The RFP required the system to be laid out as a mirror image of the existing CT-300 unit and to include detailed calculations verifying the equipment selection.

Electrical Services Division

• Electrical Services Division, LLC performed electrical construction work for the VWPA Sixth St. WTP Hypo Generation Project in Harrisburg, Pennsylvania.
• The project included design and installation of a new on-site sodium hypochlorite generation system and removal of the existing obsolete on-site hypo generation system at Veolia Water Pennsylvania’s Sixth Street Water Treatment Plant.
• ESD performed its work under subcontract to Johnston Construction Company for the electrical work associated with the Veolia Sodium Hypochlorite Generation System, Susquehanna Township Project No. C24b502.
• ESD’s scope included conduit, wire, connections, demolition / relocation of existing equipment on the mezzanine, temporary hypo system wiring, NEMA 4X PVC panels for equipment if required, miscellaneous breakers, instrumentation support, testing, startup, and closeout.
• The electrical work was based on De Nora Drawings 1 through 6, Addenda 1 and 2, BRE / ESD proposal from Ron Owens dated April 9, 2024, and the BRE / ESD control estimate.
• The project required coordination with Johnston Construction Company, Veolia Water Pennsylvania, IC&EE, De Nora / ClorTec, GR Sponaugle, Brock Solutions, plant operations personnel, equipment vendors, and project stakeholders.
• The work required compliance with the project electrical requirements, De Nora equipment drawings, Addenda 1 and 2, JCC schedule, Veolia safety requirements, OSHA requirements, submittal requirements, testing requirements, startup requirements, certified payroll requirements, Buy American requirements, and closeout requirements.
• Electrical Services Division, LLC performed electrical construction work for the VWPA Sixth St. WTP Hypo Generation Project at Veolia Water Pennsylvania’s Sixth Street Water Treatment Plant, located at 4405 North 6th Street, Harrisburg, Pennsylvania.
• ESD performed the work under subcontract to Johnston Construction Company. The ESD subcontract, No. 202409SC03, was dated effective January 21, 2025, and identified Electrical Services Division as the subcontractor and Johnston Construction Company as the contractor. The delivery location was Veolia Hypo Gen Repl, 4405 North 6th Street, Harrisburg, Pennsylvania.
• The overall project included design and construction of a new on-site sodium hypochlorite generation system at the Sixth Street Water Treatment Plant, removal of the existing obsolete on-site hypo generation system, transfer pump replacement, chemical piping work, HVAC upgrades, electrical work, instrumentation, SCADA coordination, startup, commissioning, operator training, and closeout.
• ESD’s work focused on the electrical construction required to support the sodium hypochlorite generation system improvements. The scope included conduit, wire, connections, demolition and relocation of existing equipment on the mezzanine, temporary hypo system wiring, NEMA 4X PVC panels for equipment if required, miscellaneous breakers, instrumentation support, testing, startup, and electrical closeout support.
• The electrical subcontract was based on De Nora Drawings 1 through 6, Addenda 1 and 2, the ESD / BRE proposal from Ron Owens dated April 9, 2024, and the ESD / BRE control estimate. The subcontract noted that PVC Schedule 40 conduit was assumed around chemical areas and THHN wiring was assumed for the electrical work.
• The work included conduit, wire, and connections required for the hypo generation system. The subcontract also noted that GR Sponaugle would perform on-site electrical work for conduit and wire installation, requiring ESD to coordinate its electrical scope with JCC, GR Sponaugle, and the project team.
• ESD’s demolition and relocation work included existing equipment on the mezzanine. This work supported the installation of the new sodium hypochlorite generation system and required coordination around existing treatment plant equipment, existing electrical conditions, and active plant operations.

Additional project details

• JCC replaced an aging on-site sodium hypochlorite generation system to improve reliability and simplify maintenance at Veolia’s Sixth Street Water Treatment Plant.
• The work combined process equipment replacement with chemical piping, building, electrical, and controls improvements.