What Happens in the Drain Field from Waste to Wastewater?

December 2, 2015

Drain Field SystemSince they are stable and inexpensive, subsurface soil absorption fields (also called drain fields or leach fields) usually are considered to be the best method for treating and dispersing effluent from septic tanks and other on-site wastewater treatment systems. The basic function of a drain field is to deal with the septic tank effluent by allowing it to percolate into the ground.

What Is A Drain Field?

A drain field is a wastewater disposal system. Well-designed and maintained drain fields are an effective way to remove disease-causing microorganisms from septic tank wastewater (effluent). After passing through the septic tank, settled wastewater flows out into the drain field. As it flows slowly through layers of soil, it is further treated and purified by both physical and biological processes.

Drain Field Design

Conventional gravel-filled drain fields provide simple, affordable treatment. They typically consist of a series of perforated pipes placed in long, shallow trenches that are filled with gravel and then buried below ground surface. The gravel helps to distribute the wastewater over a large area as it seeps through the gravel and into the underlying layers of soil. The size of the drain field and the capacity of the ground to absorb settled wastewater depend largely on the type and texture of the soil, the area’s topography, and the volume of wastewater produced.

Wastewater Treatment

The septic tank effluent is treated as the wastewater effluent slowly trickles from the pipes, through the gravel, and down through the soil. As the wastewater moves down through the soil, a variety of complex physical, biological, and chemical processes combine to provide treatment. Soil particles filter or chemically react with solids and organic matter from the wastewater. Bacteria and other organisms in the soil consume the organic matter in the wastewater and perform most of the treatment. As a drain field matures, microbes living in the soil break down the solids and kill the bacteria in the wastewater. Although some treatment also may occur in the gravel layer, the soil provides most of the wastewater treatment.

Something to look out for, drain fields are prone to clogging, particularly when the septic tank is not regularly maintained and the solid material is carried over into the drain field. Regular septic tank maintenance can keep your system working at its peak. FloHawks can help you keep your system maintained. Call us today!

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