TYPES OF ON-SITE SEWAGE FACILITY SYSTEMS
Conventional
Septic Tank/Soil Absorption
Standard Gravity System
Conventional septic systems have traditionally been the most commonly used technology for treating wastewater. These systems use gravity to treat and distribute wastewater in the soil.
Aerobic Treatment Unit
- Spray System
- Drip System
Aerobic units treat wastewater for homes and small businesses using the same process, only scaled down, as our municipal wastewater treatment systems use.
Non-standard treatment options
Non-standard treatment:
- is usually all forms of:
- activated sludge processes
- rotating biological contractors
- trickling type filters, o submerged rock biological filters
- recirculating sand filters
- sand filters not described in §285.32(b)(2)
- must be designed by a professional engineer when secondary treatment is required. Professional sanitarian can design when secondary treatment is not required.
- can only be installed by an Installer Class II.
Septic Tank with Drip Irrigation
A drip system distributes water to the lawn though a system of tubing installed below the grounds surface.
Drip Irrigation:
- consists of small diameter pressurized lines containing pressure reducing emitters spaced at a maximum of 30 inches.
- requires a design to be performed by either a professional engineer or professional sanitarian.
- can only be installed by an Installer Class II.
- are sized and constructed in accordance with §285.33(c)(3).
Septic Tank with Leaching Chambers
Leaching chamber systems handle wastewater in a similar manner as conventional gravel-filled trench systems. The main difference is in how the trench is constructed.
Leaching Chambers:
- are installed similar to an absorptive drainfield, however, the effluent is deposited into bottomless chambers that are linked together with solid walled pipe and are allowed a reduction in the absorptive drainfield sizing formula
- are sized and constructed in accordance with §285.33(c)(2)
- can be used in the following systems as a substitute for pipe and gravel without any reduction in drainfield sizing:
- E-T systems
- Low-pressure dosed drainfields
- Soil substitution drainfields.
Septic Tank with Gravel-less Pipe
Gravel-less pipe systems distribute treated wastewater into the soil. They are like gravel filled trench systems, except that gravel-less pipes are surrounded by geotextile fabric instead of gravel.
Gravel-less Pipe
- are installed similar to an absorptive drainfield, except the effluent in deposited into corrugated pipe with either an eight-inch or ten-inch diameter that is wrapped with geo-textile fabric
- may also be used in E-T systems as a substitute for pipe and gravel
- are sized and constructed in accordance with §285.33(c)(1)
Septic Tank with
Evapotranspiration Bed
An evapotranspiration (ET) bed treats wastewater by using evapotranspiration – the loss of water from the soil by evaporation and by transportation from plants growing there.
Lined Evapotranspiration (E-T) systems:
- are constructed similar to an unlined E-T bed with the exception of an impervious liner being placed between the excavated surface and the constructed disposal system
- can only be installed by an Installer Class II
- are sized and constructed in accordance with §285.33(b)(2)
Unlined Evapotranspiration (E-T) systems:
- are constructed with either pipe and gravel, leaching chambers, or gravel-less pipe in either a trench or bed configuration and backfilled with sand
- can be installed by an Installer Class I or Installer Class II
- are sized and constructed in accordance with §285.33(b)(2)
Septic Tank with
Low-Pressure Dosing
An LPD system treats wastewater and then pumps it into the soil several times daily. The system generally has 3 components: tanks, pump-tank for dosing, and a distribution system.
Low-pressure dosed drainfields (LPDs):
- dispose of effluent that is pumped, under low pressure, into a solid wall force main and then into perforated distribution pipe in gravel
- require a professional design by a professional engineer or professional sanitarian
- can only be installed by an Installer Class II
- are sized and constructed in accordance with §285.33(d)(1)
Absorptive Drainfields are:
- constructed with perforated pipe and gravel
- installed by an Installer Class I or Installer Class II
- sized and constructed in accordance with
Pumped Effluent
Drainfields (PEDs):
- dispose of effluent by use of a pump into small diameter perforated pipe in gravel
- can be installed by an Installer Class I or Installer Class II
- are sized and constructed in accordance with §285.33(b)(3)
Surface application disposal:
- is a method that disposes of secondary treated effluent onto the surface of the ground after Maintenance of On-Site Sewage Facilities(OSSF Systems)
- cannot apply effluent to unseeded bare ground or areas used for growing food, gardens, orchards or crops which may be used for human consumption
- must be designed by a professional engineer or professional sanitarian.
- can only be installed by an Installer Class II
- is sized and constructed in accordance with §285.33(d)(2)
Mounds:
- are pressurized absorptive drainfields constructed above the native soil surface
- must be designed by a professional engineer or professional sanitarian
- only can be installed by an Installer Class II
Types of Soil
There are 4 main types of soils; clay, sand, silt and loam. These soils will always be a mixture of one another as there is no true place with one type of soil.
