Modern septic systems have design elements different than the traditional concrete tank that connects to a field of perforated pipes. Most existing systems require good soil for the bulk of the water treatment, whereas newer techniques provide more oxygen and surface area within specialized pipes to accelerate desired bacterial growth before releasing the water into the ground.
Efficient septic systems are essential for ensuring quality drinking water. As homeowners consider replacing their aging septic systems, they have to comply with state and county regulations that have been updated since the original system was built. More distance is now required from water and well heads, for example. One lot in KPVillas remains empty in part because it is allegedly "unbuildable" if a traditional septic system were used.
A recently rebuilt system adjacent to a pond in KPVillas exemplifies a new aerobic strategy. After exiting the house, the effluent flows by gravity to two initial plastic septic tanks, including a "dousing tank" that holds a pump. Heavy waste settles into first tank akin to a traditional concrete tank.
Because the recent KPVillas example is near a pond, the liquid is pumped uphill to a distribution box in the front yard, where the warm effluent is shunted off in an equalized flow to multiple large pipes arrayed in rows. In the photo below, the white PVC pipe coming out of the box transitions to a perforated pipe surrounded by specialized materials that rests in a sandy bed. A vent pipe and lawn irrigation line passing over the distribution box are also visible.
It is within the pipe array that the modern aeration technique is most apparent, for the effluent is treated inside the pipes. The idea is to draw in oxygen across more surface area to accelerate bacteria growth, for bacteria absorb pollutants. Rather than having mere holes through which the liquid drips, the larger new pipes have skimmer tabs to capture grease and suspended solids. Ridges cool the warm effluent to ground temperature so suspended solids separate.
Several layers of special fibers wrapped around the pipe then accelerate the treatment, increase surface area, and promote even distribution. Effluent passes into an outermost layer of "geo-textile fabrics" and grows a protected bacterial surface. When sand wicks liquid from the geo-textile fabrics, air transfers to the bacterial surface.
The Presby manual notes, "The continual cycling of effluent (the rising and falling of liquid inside the pipe) enhances bacterial growth." Each 10-foot section of pipe can hold nearly 60 gallons.
There are several manufacturers of advanced treatment systems, but installers require certification first. The Indiana Design and Installation Manual from Presby Environmental, Inc., describes one example of a modern septic system that complies with Indiana law. The new system in KPVillas was installed by Accudig Excavating LLC of South Bend.
The new septic designs are suitable for many KPVillas lots because they are good for environmentally sensitive areas, such as near ponds; they accommodate the low quality, rocky soil found here; and the pipe array typically has a smaller footprint for smaller lots.
On the downside, to provide more oxygen the system requires a "high" vent pipe that is ten feet higher than a "low" vent pipe. In a recent installation, the KPVA prohibited either of those pipes from being in the yard. Hence, significantly more piping had to be run from the front yard to the side of the house, adding to the installation cost.
The proximity to the pond necessitated the long pipe run from the tanks in the back of the house to the field in the front. A weep hole allows water in the standing pipe to drain back into the tank so there is no head pressure remaining. Floats within the tank trigger an audible alarm if the liquid level exceeds a set limit, but there are likely a couple days of reserve tank space under normal use.
There are other new aerobic septic designs out there, but the least expensive option is to maintain what you have through simple practices:
Conserve water
Avoid using the garbage disposal, for it sends out a high concentration of organics into the tank. Rather, use a simple strainer first, and consider a compost bin.
Do not pour excessive chemicals down the drain; rather, dispose safely at the St. Joseph County Household Hazardous Waste sites.
Only flush toilet paper, not wipes, etc.
Pump your tank every 3-5 years; more if it gets heavy use.
St. Joseph County lists septic system resources at https://www.in.gov/localhealth/stjosephcounty/environmental-health/septic-systems/