Southerly Wastewater Treatment Plant Thickened Sludge Pumping Study

Project Overview

Ribway was retained by the Southerly Wastewater Treatment Plant to evaluate and resolve persistent issues with the thickened primary sludge (TPS) pumping system. The plant experienced insufficient pumping capacity and frequent clogging in the discharge lines, which affected overall system performance and reliability.

Background

The TPS system transfers sludge from five gravity thickeners to a sludge mixing well in the sludge control building. Operational challenges, including hydraulic inefficiencies and physical obstructions in the piping system, necessitated a comprehensive evaluation to identify root causes and recommend actionable improvements.

Ribway’s Scope of Services

Ribway performed a detailed investigation of the TPS system, which included:

• Field Investigations:
  • Internal inspections of the sludge discharge lines.
  • Hydraulic analyses to assess flow capacity and identify inefficiencies.
• System Review and Testing:
  • Assessment of the piping layout to identify problem areas such as excessive high points.
  • Testing to evaluate system performance under various operating conditions.
• Recommendations and Reporting:
  • Preparation of a detailed report summarizing findings, analyses, and recommendations for improvements.

Study Findings and Recommendations

The study identified multiple issues contributing to the operational challenges. Ribway proposed the following solutions:

• Piping Improvements:
  • Replacement of existing discharge piping with glass-lined piping to reduce clogging and improve flow.
  • Modification of the piping layout to eliminate excessive high points that hindered efficient sludge transport.
• System Enhancements:
  • Installation of check valves on the downstream end of the sludge pumps to prevent backflow and improve pump performance.

Implementation

The study, completed in 2002, served as the basis for a subsequent sludge thickening improvements project. The recommendations significantly enhanced the reliability and capacity of the TPS system when implemented.

Summary

Ribway’s comprehensive investigation and recommendations provided a long-term solution to the TPS system’s challenges, improving operational efficiency and reliability at the Southerly Wastewater Treatment Plant.