Not all residential properties will be suitable for a conventional septic system, thanks to high groundwater tables, shallow bedrock, or challenging soil conditions. That’s when you and your plumbing company should instead look into installing a mound septic system.
At Valentine Plumbing, our team specializes in installing mound systems that provide reliable wastewater treatment even in the most difficult site conditions. Let’s take a look at how these innovative systems work and whether they are a good fit for your home.
If you have immediate questions about your mound septic system, please contact our team directly at (920) 788-5369 or contact us online.
What is a Mound Septic System?
The mound septic system type is an alternative wastewater treatment solution that utilizes an elevated sand mound to treat and dispose of effluent when soil conditions aren’t suitable for standard drain fields. Instead of relying solely on natural soil for filtration, mound systems create an artificial treatment environment above ground level.
The mound septic system consists of 1.) a septic tank, 2.) a pump chamber, and 3.) a specially constructed sand mound that serves as both the treatment and disposal area for wastewater. This differs from a conventional septic system, which just has the tank and the drain field. We detail more about the components of the mound septic system below.
When Are Mound Systems Necessary?
Mound septic systems become essential when property conditions present challenges for conventional systems. These include:
- High Groundwater Tables: When groundwater sits too close to the surface, there isn’t enough unsaturated soil for proper wastewater treatment. Mound systems resolve this issue by elevating the treatment area above the water table.
- Shallow Bedrock: Another common issue that calls for a mound system installation is shallow bedrock. Properties with bedrock close to the surface lack adequate soil depth for conventional drain fields. The mound septic system helps by providing the necessary treatment depth artificially.
- Slowly Permeable Soils: Does your property have slowly permeable soils? Clay-heavy or compacted soils that drain too slowly can cause conventional systems to fail. So instead, mound septic systems use engineered sand media for controlled percolation.
- Rapidly Permeable Soils: Conversely, very sandy or gravelly soils that drain too quickly don’t provide adequate treatment time. The mound system controls the flow rate for proper filtration.
- Sloping Terrain: Lastly, if your residential property has a sloping terrain, the right choice for your property will likely be a mound septic system. Steep slopes that would cause effluent to flow too rapidly can be managed with properly designed mound systems.
Components of a Mound Septic System
Ok, now let’s talk about what a mound septic system is comprised of:
1. Septic Tank
Like conventional systems, in a mount septic system, the wastewater first enters the septic tank where the first stages of the treatment occurs.
At this point, the solids settle, scum floats, and the beneficial bacteria start breaking down organic matter.
2. Pump Chamber
Unlike gravity-fed conventional systems, mound systems require a pump chamber to move effluent from the septic tank to the elevated mound. The pump chamber contains:
- Submersible effluent pump
- Float switches to control pump operation
- Alarm system to alert homeowners of pump failures
- Electrical controls and backup systems
3. The Mound Structure
The mound itself is a carefully engineered structure consisting of:
- Base preparation: The natural soil is scarified and leveled
- Sand fill: Special sand media provides the treatment environment
- Distribution system: Pressure distribution pipes ensure even effluent spreading
- Topsoil and vegetation: Protects the mound and manages surface water
How Mound Septic Systems Work
Step 1: Treatment in the Septic Tank
The treatment process starts when the wastewater from your home first enters the septic tank, where it undergoes the same initial treatment as conventional systems.
Heavy solids settle to form sludge, oils, and grease float as scum, and the middle layer of partially clarified effluent prepares for the next treatment stage.
Step 2: Pumping to the Mound
When the effluent level in the pump chamber reaches a predetermined point, float switches activate the submersible pump.
The pump delivers a measured dose of effluent through a force main to the distribution system within the mound.
Step 3: Pressure Distribution
Unlike conventional systems that rely on gravity distribution, mound systems use pressure distribution to ensure even effluent spreading across the entire sand bed.
Small-diameter pipes with precisely sized holes, called orifices, work to distribute the wastewater evenly.
Step 4: Treatment in the Sand Media
As effluent moves down through the engineered sand, several treatment processes occur:
- Physical filtration: Sand particles trap suspended solids
- Biological treatment: Beneficial microorganisms consume organic matter
- Nutrient removal: Nitrogen and phosphorus are reduced through biological processes
- Pathogen removal: Harmful bacteria and viruses are filtered out
Step 5: Final Infiltration
After treatment in the sand mound, the cleaned effluent infiltrates into the natural soil beneath the mound, where final polishing occurs before reaching groundwater.
Design Considerations for Mound Septic Systems
Soil Testing and Site Evaluation
Before designing a mound system, Valentine Plumbing conducts a thorough site evaluation.
This includes 1.) a percolation test to determine the rate of soil absorption on your property, 2.) soil boiling analysis to check the groundwater and bedrock levels, 3.) topographic surveys to assess the level of site drainage, and 4.) soil texture analysis to select appropriate sand media.
Hydraulic Loading Rates
Mound systems must be sized according to daily wastewater flows and soil conditions.
We calculate loading rates based on your 1.) household size and level of water usage in your home, 2.) natural soil characteristics beneath the mound, 3.) your climate, and 4.) local health department requirements.
Distribution System Design
The pressure distribution network requires precise engineering to ensure 1.) even effluent distribution across the sand bed, 2.) a good level of dosing frequency and volume, 3.) proper orifice sizing and spacing, and 4.) adequate system redundancy.
Need a septic service? Contact the Valentine Plumbing team today or call now to schedule a service.
4 Advantages of Mound Septic Systems
1. Effective Treatment
Properly designed mound septic systems often provide much better effluent treatment compared to conventional systems due to the controlled environment and engineered media.
2. Site Flexibility
Mound systems make septic treatment possible on sites where conventional systems would fail, opening up development opportunities on challenging properties.
3. Environmental Protection
The enhanced treatment capabilities of mound systems provide better protection for groundwater and surface water resources.
4. Longevity
With proper maintenance, mound systems can provide decades of reliable service, often outlasting conventional systems in difficult soil conditions.
Maintenance Requirements for Mound Systems
Mound septic systems require more active maintenance than conventional systems due to their mechanical components. Here is an overview of what’s needed for mound system maintenance:
Regular Pump Maintenance
- Yearly pump inspection and testing
- Float switch calibration and cleaning
- Electrical connection checks
- Alarm system testing
Septic Tank Pumping
- Regular pumping every 3-5 years (same as conventional systems)
- More frequent pumping may be needed to protect the pump
Mound Care
- Protecting grass and plants on the mound surface
- Managing surface water drainage
- Preventing soil compaction from foot traffic or equipment
- Monitoring for settlement or erosion
System Monitoring
- Quick response to pump alarms
- Watching for wet spots or odors around the mound
- Tracking water usage to prevent system overloading
- Yearly professional inspections
Contact Valentine Plumbing for a Mound System Installation
At Valentine Plumbing, we’re trusted experts serving the Fox Cities and Northeast WI. Since 1973, we have provided professional plumbing and septic system installations, repairs, replacements, maintenance, ordered upgrades, and emergency services. We proudly serve Appleton, Neenah, Menasha, Oshkosh, and the Green Bay area.
Our team of licensed plumbing professionals has the experience, products, and equipment necessary to tackle even the most challenging site conditions. With our expertise in mound septic systems, you can turn even the most challenging property into a building site for a mound septic system installation. Contact us online or by phone at (920) 788-5369 today to schedule a service!
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