Southerly Wastewater Treatment Plant (S76) Sludge Thickening Improvement Project

Overview

Ribway was selected to collaborate with the City of Columbus, Ohio, as part of a consulting team to deliver process and electrical engineering design services for a $63 million sludge thickening facility at the Southerly Wastewater Treatment Plant. This project addressed the critical need to replace the existing sludge thickening infrastructure, which was insufficient to meet the anticipated future demands of wastewater treatment in the region.

Project Scope

The new sludge thickening facility incorporated advanced engineering solutions to enhance operational efficiency, ensure reliability, and support future growth. Key elements of the design included:

• Centrifuge Power Systems: The electrical power system was engineered to supply four (4) 500 HP and one (1) 300 HP centrifuges equipped with variable frequency drive (VFD) motor controllers.
• Electrical Substations and Motor Control Centers: A state-of-the-art 480-Volt 4,000 KVA dual-unit substation and two (2) 480-Volt 5,000 AMP motor control centers were installed. Additionally, the main feed to the North Incinerator Building was upgraded with a larger 480-Volt 2,000 KVA dual-ended substation.
• Lighting and Power Distribution: Comprehensive interior and exterior lighting systems were designed, along with electrical connections for sludge feed pumps and the facility’s PLC control system.

Electrical Design Highlights

A significant aspect of the project involved conducting an extensive electrical power loading study to ensure proper sizing and compatibility of all systems. The study covered:

• Process equipment
• HVAC systems
• Lighting
• Control devices

The study’s findings informed the sizing of 4160-Volt and 480-Volt electrical equipment, ensuring the facility’s capacity to meet current and future needs.

Challenges and Solutions

One of the most complex challenges was maintaining uninterrupted power to the existing sludge thickening equipment during construction. Ribway developed a detailed construction schedule and implemented temporary power solutions to guarantee seamless operations throughout the upgrade process.

Programmable Logic Controller (PLC) System

Ribway also designed an advanced central Programmable Logic Controller (PLC) system to streamline operations. The central PLC communicates with individual vendor-supplied PLCs for each of the five (5) centrifuges. This system enables precise monitoring and control of sludge feed equipment and support systems, ensuring optimal performance.

Project Timeline

• Design Completion: August 2009
• Construction Start: November 2009
• Project Completion: March 2012

Results and Impact

The Southerly Wastewater Treatment Plant Sludge Thickening Improvement Project has significantly enhanced the plant’s capacity to process wastewater efficiently and sustainably. The upgraded facility ensures reliable operations, supports future expansion, and reinforces the City of Columbus’s commitment to environmental stewardship and infrastructure resilience.