The soil absorption area may be an in-ground seepage bed, a set of trenches, or an elevated sand mound. The type of system installed will depend on the slope of the property, the depth of usable soil and the percolation rate.

State law requires that there be at least four feet of usable soil for the effluent to percolate through before it reaches the water table.

How it Works

The soil absorption area receives the liquid effluent from the septic tanks and distributes it over a specific area. The effluent then filters through the soil under the pipes and is treated chemically and bacterially by the components of the soil. The size of the soil absorption area is based on the size of the house and the percolation rate of the soil.

Equal Distribution

Equal distribution of the effluent is very important to the proper functioning of the system. Uneven distribution of the effluent could result on one of the areas being overloaded, leading to a failure of the system. Most trenches and in-ground bed systems utilize gravity distribution to the absorption area from the septic tanks.

Cesspools and septic tanks with seepage pits are no longer permitted for new installations or as corrective measures for malfunctioning systems. However, many older homes with systems installed prior to 1970 may have these systems presently in use.

Cesspools

Cesspools are constructed of open-jointed walls (concrete block or stone) and open bottoms. The solids in the wastewater settle to the bottom of the cesspool, while the effluent seeps through the jointed walls and bottom. If the cesspool is not properly cared for, the sidewalls and bottom tend to plug up with solids. This may result in sewage backing up into the house or being discharged to the ground surface.

Septic Tanks With Seepage Pits

The sewage system with a septic tank and seepage pit partially reduces the clogging problems inherent in cesspools. The septic tank provides for the separation of solids from the liquid while storing the accumulated solids. The seepage pit allows the effluent from the septic tank to infiltrate into the soil. The seepage pit is constructed similarly to a cesspool, except that there is a layer of rock or aggregate placed around the concrete blocks or stone and the open bottom.

Current Regulations

Current state regulations require better treatment of the effluent than either the cesspool or septic tank with a seepage pit can provide. These older types of systems frequently lead to the contamination of groundwater due to the improper renovation of the sewage effluent prior to reaching the water table. Current methods of sewage disposal have been designed to provide for more effective renovation of the effluent. They utilize more soil area to absorb the-effluent and provide for aerobic (oxygenated) conditions in the soil which are more efficient in treating the waste materials.

The elevated sand mound system is used in areas of the Township with reduced permeability, shallow soils and poor drainage characteristics. Soils in these areas require the addition of sand above the ground to provide for adequate renovation of the sewage prior to reaching the water table.

Absorption Area

The absorption area is constructed similarly to a standard seepage bed or trench, except that the system is required to use pressure distribution and a layer of sand must be placed between the crushed stone and the natural soil cover. A soil berm is placed around the mound to protect it and to provide a suitable base for the establishment of a vegetative cover.

Pump Failures

The mound is preceded by a dosing tank which must be equipped with an audible and visual alarm system to alert the homeowner when a pump failure occurs. It is very important that the homeowner make the necessary repairs to the pump system as soon as the problem is detected or significant damage could be done to the mound. This type of damage could result in very expensive repairs.