Traditional septic systems are used throughout the United States in both urban and rural environments, wherever public sanitary sewer systems are unavailable. Although each residential septic system is a custom design based upon the number of design factors, all septic systems have a septic tank, distribution box and a drain field in common.
Sewage and wastewater from the home flows into a precast concrete septic tank located in the yard of the home, where the organic solids are digested by enzymes or bacteria, which have been introduced into the tank. Non-organic materials are also collected here, which are removed by periodic septic tank pumping.
The distribution box is located at the beginning of the drain field and has a single solid pipe running into it from the septic tank and multiple pipes running out of it and into the drain field. Then purpose of the distribution box is to allow the fluids from the septic tank to be evenly spread out into the entire drain field.
The drain field is where the fluids are absorbed into the soils. The field will consists of a number of trenches that vary in depth from four to six feet deep. Half of the trench is filled with stone. A 4” perforated pipe is placed in the gravel of the trench, which is then backfilled. In many cases, a filtration fabric will be placed on top of the stone to prevent soil from contaminating the stone or clogging the pipe. The length of the trenches varies due to the septic load on the system, which is determined by either the number of bedrooms or bathrooms., as well as the soil conditions.
Posted on behalf of Keith Lee, Metro Septic and Plumbing
