Monday, July 27, 2009

Homeowners: Do you have an E/One grinder pump?

E/One is looking for homeowners who have E/One grinder pumps installed at their homes. Whether they’re 6 months old or 26 years old, we’re interested in your opinions and experience. Please send an email to with your name, city/state and the subject line “Homeowner Survey Signup.” We will NOT sell your email address to anyone – all contact information collected is solely for the purpose of knowing who uses our grinder pumps.

Wednesday, July 8, 2009

Sewer System Technology: Vacuum Sewer vs Pressure Sewer

At first thought, a vacuum sewer system sounds like an easy, convenient alternative to a gravity sewer system. Vacuum sewers require shallow trenches, small mains, and can be used in flat or rocky areas. No individual pump stations are required at each home. But they aren’t ideal for every situation or every location, and require regular maintenance.

How a Vacuum Sewer System Works
Vacuum systems use differential air pressure to move wastewater. The system consists of one or more vacuum stations, collection system piping, valve vaults and vacuum interface valves. The sewage is transported in small diameter pipes placed at variable grade and deflection underground. The wastewater is drawn to the station and pumped to a wastewater treatment plant. Vacuum interface valves regulate the entry of wastewater and air from the valve vault into the collection system piping.

Vacuum System Disadvantages
There are a number of disadvantages to vacuum systems. First, while the mains are small and require shallow burial (just below the frost line), they are limited to approximately 20 feet of head. The sewer lines must have a specific profile of pockets or running traps, so installation requires the same attention to grade as a gravity sewer main.

The biggest disadvantage is system size. The central vacuum stations require a large capital investment, so a system for less than 50 homes is not economically feasible.

Pressure Sewer Systems
Pressure sewer systems use pump installed at each home to grind wastewater and move it to the sewer system. Pressure sewer mains are also small-diameter pipes that are buried just below the frost line, but follow the contour of the land – therefore, they don’t require the pockets or running traps that vacuum systems need. Head is limited by the capabilities of the grinder pump installed at the home (185 ft for E/One pumps), allowing for uphill pumping.

Small systems are also economically feasible. A few homes – or even one home – can connect to the sewer system at a reasonable cost. E/One’s grinder pump does not require preventive maintenance and boasts an average mean time between service calls of 8 to 10 years. Visit the Case Studies section of E/One’s web site to read more about communities that have used E/One Sewer systems.

Thursday, July 2, 2009

How do I know which size grinder pump to choose?

E/One grinder pumps are available with a variety of tank sizes. To determine which size grinder pump station is needed, you’ll need to consider a few factors:
  • Wet well and discharge piping must be protected from freezing
  • Model and basin size must be appropriate for incoming flows, including peak flows
  • Appropriate alarm device must be used
  • Suitable location

Daily flows above those recommended may exceed the tank’s peak flow holding capacity and/or shorten the interval between pump overhauls. E/One should be consulted if higher inflows are expected. The final selection will have to be determined by the engineer on the basis of actual measurements or best estimates of the expected sewage flow. The recommended flows for each of E/One’s grinder pump stations are available in the Product Catalog.