"Very proud to be the installer of the septic system for Extreme Makeover Home Edition home for the Koepke family in Osceola (Dundee) Wisconsin. Episode to air on ABC late November 2006"

The Herr family is in their fourth generation in the plumbing industry, specializing in the design, installation, and management of every type of Privately Owned On-site Wastewater Treatment System. These systems include conventional septic systems, trench systems, mound systems, in ground pressure systems, at-grade systems, mound systems, aerobic systems, sand-filter systems, experimental systems, etc. for new construction or replacement.

MOUND SYSTEMS
Mound systems, conventional "septic" systems, in-ground pressure systems, at-grade systems, trench systems, etc. are all types of systems used to treat wastewater from structures not served by public sewer. They all do basically the same thing, they are just designed differently to compensate for differing lot constraints and soil conditions.

A MOUND SYSTEM refers to a system in which the soil absorption part of the system must be designed and installed literally on top of the existing grade to assure the wastewater is properly treated on sites that have high groundwater or bedrock.

In all Privately Owned Wastewater Treatment Systems (POWTS), including both mound and conventional systems in Wisconsin, the wastewater exits the house and enters a septic tank where the water is partially treated. In a septic tank the inlet and outlet of the tank are both near the top of the tank, allowing the larger solids to settle to the bottom of the tank. A portion of the solids accumulating on the bottom of the tank are eventually "broken down" by anaerobic bacteria, and the balance pumped out when you have your system periodically pumped. Greases, oils, and lighter solids which float on the top of the water in the tank are prevented from exiting ( which leads to clogging of the soil absorption bed), by baffles which cover both the inlet and the outlet of the tank, allowing only relatively cleaner water near the middle of the tank to exit.

Remember: both conventional septic systems and mound systems begin by having the wastewater partially treated in a septic tank and must be periodically pumped for proper maintenance.

After the partially treated water exists the septic tank the water may follow gravity into a conventional (below grade) soil absorption bed, or flow into a pump tank to eventually be dosed into a mound system under pressure.

A mound system in Wisconsin is a pressurized equal distribution system, which means when water is "dosed" to the mound (four times max in a 24 hour period) the wastewater is equally distributed under pressure. This means you use the entire square footage of the mounds soil absorption area to treat the water. The pressurized equal distribution is due to the distribution pipes in the mound being only 1" to 1&1/2" in diameter with small, specifically sized holes drilled at specific spacings. This assures the most equal distribution possible.

"What determines if I need a mound system or a conventional septic system?"

A certified soil tester must complete a detailed analysis of your soil characteristics (and other site limitations i.e. set backs, slopes, etc.) to determine the type of system your lot requires. The most important item the soil tester is looking for is depth to a "limiting factor" such as high groundwater or high bedrock. Wisconsin administrative code ILHR 83 (at this time) mandates a 3 foot vertical separation between the bottom of the soil absorption system and high groundwater or high bedrock in most instances.

Example: If the soil test determines that you are in suitable soil and the highest groundwater is 70 inches in the ground, 3 foot vertical separation would put your "system elevation" (or bottom of soil absorption system) 34" deep in the ground. A subsurface "gravity" system is what most people consider to be "conventional": a system in the ground.

If that same soil test showed the limiting factor at only 24 inches below the ground surface, how would you design a system to acheive the minimum required 36 inch vertical separation? By artificially creating the bottom of the soil absorption system 12 inches above the ground by placing 12 inches of a medium washed sand over the top of the ground and then installing your distribution bed of stone and piping on top of the sand. When this system is covered up with topsoil it creates a mound, because it's designed from the ground up instead of below the surface of the ground.