Septic drain field

Several factors may reduce observed percolation rates when the drain field receives anoxic septic tank effluent:[4] Just as a septic tank is sized to support a community of anaerobic organisms capable of liquefying anticipated amounts of putrescible materials in wastewater, a drain field should be sized to support a community of aerobic soil microorganisms capable of decomposing the anaerobic septic tank's effluent into aerobic water.

Hydrogen sulfide odors or iron bacteria may be observed in nearby wells or surface waters when effluent has not been completely oxidized before reaching those areas.

[8] Septic tank effluent with soluble organic compounds passing through the biofilm forms a mounded lens atop the groundwater underlying the drain field.

Biofilter technology may allow higher-density residential construction, minimal site disturbance, and more usable land for trees, swimming pools, or gardens.

The nematode community in the resting drain field continues feeding on the accumulated biofilm and fats when the anaerobic septic tank effluent is no longer available.

This natural cleansing process may reduce bioclogging to improve the hydraulic capacity of the field by increasing the available interstitial area of the soil as the accumulated organic material is oxidized.

Laundry bleach may slow or stop microbial activity in the drain field, and sanitizing or deodorizing chemicals may have similar effects.