What is a Mound Septic System?
A mound system is an alternative
to the traditional trench system for disposing of septic tank
effluent.
If your property has thin soil over rock, or a high water table, a
trench septic tank system will not operate properly. In that situation, many
local authorities will permit a mound system.
In a mound system, a timer is set to run a pump about four times per day. The
pump takes stinky (anaerobic) effluent discharged from the septic tank and sends it to
one or more mounds for final purification. These mounds consist of a
layer of sand over a layer of gravel, and some PVC pipes with holes
drilled in them.
The pipes receive the pumped septic-tank effluent and distribute it over the
gravel, which spreads it out over the sand. The system operates
aerobically (with oxygen from the air), which permits aerobic bacteria to eliminate the odor and
pollutants from the effluent. The purified effluent leaves the bottom
of the mound and is safe for the environment.
It is important to avoid locating plants on the mound whose roots may damage the mound or clog the openings in the distribution lines.