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Sand Creek Water Reuse Facility PLC Conversion and Improvements

City of Aurora
Aurora, Colorado

Project Overview

Process control system replacement improves productivity and user experience for plant operations staff.

The Sand Creek Water Reclamation Facility (SCWRF) plays an important role in the City of Aurora’s efficient and renewable water supply strategy, and has become even more critical as the City implements its 2020 Non-potable Water Strategic Plan (NPWSP). Since the last major SCWRF upgrades were completed nearly 20 years ago, improvements to key processes are needed, including the control systems that operate the Facility’s clarifiers, blowers, and mixed liquor return (MLR) pumping.

This Design-Build project was implemented in close cooperation with City operations staff whose responsibilities require regular interface with the plant control system, and the City’s SCADA Tech-Ops team who is responsible for maintaining the system. As the City opted to employ the Progressive Design-Build (PDB) Delivery method for the project, Carollo provided the City a Design-Build team with the requisite planning, design, and construction experience necessary to implement this project without impacting normal plant operations.

Carollo’s DB team approach focused on implementing and maintaining constant communication and interaction with plant staff to develop a customized control system meeting the needs of the City’s end users, within the constraints of the City’s budget. Accomplishing this goal required conducting a series of technical workshops to understand and subsequently implement the City’s operation’s team project vision. With this vision, Carollo developed the design for the process control system, programmed the PLC’s, procured all of the equipment, and performed field construction resulting in the smooth cutover from the existing to new control system. Major features of the completed project include:

  • Designed and installed five new control panels
  • Programmed five new PLC’s
  • Developed 209 custom trends to monitor plant performance
  • De-terminated and re-terminated 1,812 control wires to support the installation of the new controllers
  • Tested and verified 1,226 system alarms

Additionally, numerous control upgrades were implemented including plant-wide access to the SCADA network, installation of networked security cameras, installation of a fiber optic backbone loop, and system-wide network replacement and configuration.

Results and Highlights

Resulted in the complete replacement of all of the Programmable Logic Controllers (PLC) at this 5 MGD Water Reuse Facility.

Plant operations and critical biology were not interrupted during the replacement project.

Plant control room was modernized with ergonomic control consoles, multi-screen control monitors, and communications equipment.

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