A drainfield is a very important piece of a septic system. A septic tank, the septic drain field and the associated piping, make a complete septic system.
The septic tank will have an inlet and an outlet. The outlet to the drainfield will have a filtering device which prevents solid waste particles from passing on to the drain field.
On average, a drainfield will have a series of pipes buried 18” within the ground on top of a bed of gravel. These drainage pipes sit parallel with each other and are all linked together coming out of the distribution box.
The wastewater from showers, toilets, washing machines and sinks enter the septic tank through pipelines. The liquid wastewater (effluent) is discharged by gravity or pressure to an absorption field (also known as a drainfield or a leachfield). In most gravity systems, the wastewater flows into a distribution box, and from there, effluent distributes equally among the trenches in the drainfield.
The type of soil greatly impacts the effectiveness of the drainfield. Clay soils may be too tight to allow much wastewater to pass through, and coarse or sandy soil may not provide enough treatment to destroy pathogenic bacteria and viruses from entering a well or surface water supply. This process works best where the soil is somewhat dry, permeable, and contains plenty of oxygen for several feet below the drainfield.
The drainfield is where the final treatment takes place via Mother Nature. As wastewater trickles out of the pipes and through the gravel layer, microorganisms treat the effluent as it passes through the pore spaces. The soil micro-organisms percolate the effluent downward and outward, eventually entering ground or surface water.
Posted on behalf of Shawn Bynum, Bynum Plumbing
