Low Pressure Sewer Systems vs Gravity Sewer Systems

At the heart of the E/One Sewer system is the toughest, hardest working grinder pump in the industry. The E/One Extreme Series reflects everything we've learned in more than 40 years as the originator and leader in the category of low pressure sewer systems.

Benefits of Pressure Sewer Systems
As communities migrate from septic tanks to central sewer systems, they will consider pressure sewer and gravity sewer systems. "The Secret Life of Pressure Sewers" details the benefits of pressure sewer systems — for one, they use small, 2- to 4-inch force mains that follow the contour of the land and are installed just below the frost line, eliminating the need for large, deep trenches.

Gravity sewer systems may also require large, expensive lift stations. At Great Sky in Canton, Georgia, USA, a gravity sewer system would have required 20 lift stations because of the steep, hilly terrain. A pressure sewer system cut the number of required lift stations to three.

Other benefits include:

  • Proven engineering and design
  • Ideal for every terrain and building environment
  • Cost-effective central sewer solution for new construction or retrofits
  • Engineering and technical support during design, construction, installation and operation
  • Reliable performance means reduced O&M costs
  • When needed, E/One grinder pumps are easy and safe to access and service
  • Designed to keep maintenance to an absolute minimum

E/One offers sewer system design assistance and software. Visit our Design Center to learn more.

Pump Selection
Constant, predictable pump output is the foundation for proper hydraulic design. It enables the engineer to minimize retention time, pump wear and deep scouring action at effective levels. E/One's semi-positive displacement (SPD) grinder pump was developed for wastewater application. Pumps & Systems magazine recently featured an article about SPD pumps for pressure sewer systems.

Frequently Asked Questions
Q: What is the difference between E/One's grinder pump and centrifugal pumps? Why is an SPD pump important in a pressure sewer system?

A: E/One's grinder pump lends itself to complex system designs because of its nearly vertical pump curve and the resulting nearly identical flow rate allows a wide variety of discharge heads. The predictable flows of the SPD pumps provide tolerance of widely varying system pressures.

The use of SPD grinder pumps is crucial to the success of a pressure sewer system. The performance characteristics of SPD pumps assist in maintaining a sewer network free from blockages. When deposition of solids occurs, tending to block the pipe, centrifugal pumps will move toward shut off, reducing flow and velocity and increasing the tendency to block the pipe. SPD pumps constantly scour the lines to prevent buildup because flow is maintained although pressure or head increased, effectively scouring the pipe.

Q:How is growth in the community handled?
A: Typically, pressure sewer systems are designed for future growth. When designed properly, additional zones can be added as the community grows. New developments will require analysis as they would if a gravity system was used. Existing communities can manage growth simply by adjusting the diameter of the street mains to meet only current or projected future needs.

E/One offers sewer system design assistance and software. Visit our Design Center to learn more.