Alternative Septic Systems
What is an engineered septic system?
Alternative septic systems or engineered septic systems are often used in scenarios where a conventional septic system cannot be installed. The limiting factors on the placement of a conventional septic system are three: groundwater table, bedrock, and local health ordinances. Alternative septic systems are required by the local health departments when the soil or groundwater conditions are not ideal.
Types of alternative septic systems
Mound Septic System
Mound systems are used in cases of shallow soil depth or bedrock or high groundwater. The clean water or the effluent leaves the septic tank and goes to a pump chamber that distributes it in prescribed doses to a drain field trench. Then it filters through the sand.
Aerobic Treatment Unit
Aerobic treatment units are used in places with inadequate soil conditions, the water table is too high or the lot is small. Aerobic treatment units are similar to municipal sewage plants.
The aerobic system works to inject additional oxygen into the septic tank to increase the activity of the natural bacteria and clean the water further.
Alternative septic systems: Constructed Wetland System
It is a replica of the treatment processes that occur in natural wetlands. Constructed wetland systems can work in almost any type of soil.
Here is a man-made shallow pond lined and filled with rock, tire chippings, microbe and plants. The effluent exits the septic tank and passes through the media in the wetland cell to break down the pollutants.
Then the wastewater exits the wetland cell and flows into a drain field for further treatment.
Drip Distribution System
A drip distribution system can be used with shallow soils, clays and on steep slopes.
With this type of system, no large amount of soil is needed but a large dose tank that is needed to sit after the septic tank and regulate the delivery of wastewater to the drip absorption area.
Recirculating Sand Filter System
This is a large box filled with sand. It is 2-4 feet deep with a watertight liner of concrete or PVC. Sand filters can be built above or below ground.
The effluent leaves the septic tank to a pump chamber before it goes to the sand filter. Then water is pumped at low pressure through the pipes at the top of the filter.
Finally, the effluent filters through the sand before it is discharged to the drain field.
A chamber system is suited to areas with high groundwater tables or a scarcity of gravel. It is a standard septic system with an alternative leach field without gravel.
This type of system offers significant savings on gravel and the smaller size of the drain field.
The wastewater leaves the septic tank to a series of connected chambers. Inside the chambers, microbes on the soil treat the effluent.
Because they have more moving parts and electrical components, alternative septic systems are more expensive than conventional septic systems.
Not anybody can install an alternative septic system. They require expert design and installation. Septic Works LLC is a specialist with the technology used in both cases of the design and the installation.