Lochmueller Group was tasked by Logansport Utilities (Indiana) to help with the Logansport Utilities’ (LU) Wastewater Treatment Plant (WWTP) headworks system, which had exceeded its useful life. Most of the original structures and equipment were constructed and installed in the 1950s and have shown significant signs of wear. As a result of the potential for catastrophic failure, it was determined that the construction of a new headworks facility was necessary and was included in LU’s Capital Improvement Plan.
The project was developed using a phased approach by erecting the new headworks facility adjacent to the existing, allowing for continued operation of the plant during construction. The latest technologies were evaluated, and the result consisted of a redundant set of chain and rake screens for the primary screening, a hydraulically induced vortex flow grit removal system and cycle grit washing and dewatering system, and an influent pumping system. The design approach toward the electrical, instrumentation, and control system focused on maximizing operational continuity during failures, and flexibility during operations and maintenance procedures.
The new facility is powered from the facility’s existing medium-voltage distribution system, requiring temporary power generation to continue operation of the existing headworks facility, while the existing distribution system was extended to the new addition. The construction sequence was carefully designed to minimize the duration and quantities of plant outages. Once the new headworks facility becomes operational, the existing headworks operations and electrical equipment will be removed and consolidated down to the essentials.
The design of the power distribution system considered the need for flexibility and continuity during operations and maintenance procedures, focusing on keeping the plant operational during the maintenance or replacement of equipment that will occur in the future. The distribution system is designed so that the two major process trains, consisting of the screening and influent pumping, a reserved from independent distribution busses, allowing the operators to de-energize one half of the headworks process while the other half remains operational. This purposeful design builds in system flexibility and reduces the complexity of operation and maintenance procedures.
The influent pumping system consists of four pumps controlled by variable frequency drives, the operation of which are controlled by level and flow. Each of the 150 horsepower drives is equipped with a manual across-the-line bypass contactor system to allow for continued operation in the event of a drive failure. Additionally, the influent pumping control system is designed so that it can operate independently from the PLC-based control system through a relay-based system in case of a controller failure.
With this project, a new state-of-the-art supervisory control and data acquisition system (SCADA) is being provided, upgrading the plant’s antiquated system with the latest technology. The new control panels and operation system are networked together using a combination of fiber optics and ethernet technologies. The proposed control system will integrate other major assets of LU, including several lift stations via radio communications.
This project demonstrates Lochmueller Group’s capabilities in the design of Electrical, Instrumentation, and Control Systems. Lochmueller’s understanding of the critical nature of these processes gives them a unique perspective into the challenges faced by Water and Wastewater Facilities and makes them an authority on solving complex challenges and problems.
