Conference Agenda

Abstract Title

The Industry Misunderstanding of Low-Pressure Sewer: Flow Study and Analysis of Gravity vs Low Pressure Collection Systems.

Presentation Description:

FUDKnox serves 100,000 people in East TN. The collection system consists of 600 miles of line, 200 of which are low pressure sewer with 4000 low pressure pumps. After multiple years of sewer rehabilitation in the gravity system it became apparent that the lower pressure system was operating on a much more efficient and economic schedule due in part to almost nonexistent I/I. FUD Knox determined to validate what the finance and operational staff were observing through an analysis of sections of the gravity and low- pressure piping. A consultant was retained to evaluate flow data and operations cost.

FUDKnox has a comprehensive flow monitoring program that keeps 75 flow monitors deployed in the collection system. In 2016 flowmeters were installed at predetermined areas in both the gravity and low-pressure systems. Information collected for 12 months insured data from multiple rain events was captured. All operations cost were captured for the same time frame. At the end of the 12-month period all information went through engineering analysis and a technical report published.

The compiled information was even more surprising that suspected. During multiple heavy rain events, I/I was almost nonexistent in the 4 low-pressure subbasins where flow meter was installed and monitored. In the gravity subbasins that were analyzed, I/I was detected and had a direct effect on the wet weather peaking capacity at the wwtp.

KEY TAKEAWAY

The theme for the 2023 PNCWA Conference is “Catalyzing A Sound Future for Water”. One definition of catalyze is to cause an action or process to begin. The author of this abstract was once a Program Manager for a large consulting firm with an expertise in sewer rehab programs and consent order compliance. Low-pressure was never considered a viable solution because of no understanding of its functionality. Based on the number of service providers across North America that have contacted FUDKnox to better understand our low-pressure methodology, it appears the application of low pressure as a solution is gaining traction.

For over 50 years, pressure sewer systems powered by grinder pumps have emerged as an effective solution for septic tank replacement sewer projects.

A pressure sewer system consists of a network of small diameter pipes that are pressurized to move wastewater from individual homes or buildings to a central collection point, typically a treatment plant or a larger sewer system. Grinder pumps, which are installed at each individual property, are used to break down solid waste and pump it into the pressurized pipes.

One of the key applications of pressure sewer systems is in “septic-to-sewer” projects. In these projects, an established community has chosen to enhance environmental and public health quality with a wastewater collection system. Beyond the technical advantages of pressure sewers, the practical and logistical simplicity of deploying the system often results in a more affordable and sustainable solution for the community. Specifically, the footprint of pressure sewers is much smaller than alternatives like gravity sewers or septic tank effluent pumping (STEP) systems. Furthermore, the constructability of pressure sewers enables minimal disruption to the local communities, avoids damage to private property and existing vegetation, and returns valuable land back to the community.

This presentation will highlight the benefits and best practices of grinder pump pressure sewers in these septic-to-sewer projects. These best practices are the results of lessons learned over the last several decades of working in similar projects in the Pacific Northwest, across the United States, and across five continents. Examples of these best practices in action will be shared through various real-world projects and case studies.

At the conclusion of this session, the attendees should recognize the benefits, differentiators, common missteps, and keys to successful septic-to-sewer projects. By demonstrating these factors, the audience should gain an appreciation for how stakeholders can leverage pressure sewers and how the benefits of pressure sewers will be a catalyst to facilitate more septic-to-sewer projects as we collectively seek to improve environmental quality of life.