Sand Filter Septic System Explained

A sand filter septic system is a good solution for waste water treatment problems in areas with insufficient soil. These systems consist of the septic tank, pump chamber, sand filter and drain field. Sand is used to make up for the inadequate amount of soil at the site. The sand filter may consist of a large concrete box filled with sand.

A layer of gravel is laid above the sand with a network of narrow pipes installed in the gravel. It is important that the sand grains are a similar size. If large and small grains are used, the small grains will occupy the space between the large grains. This may cause the system to clog. Sand filters may occur above the ground or be buried in the ground.

How it Works

Wastewater discharged from the household enters the septic tank for treatment. Once treated, the water is discharged into the sand filter through the network of pipes. The water is discharged under low pressure to ensure uniform distribution into the sand bed. As the effluent is discharged from the pipes above the sand bed, it slowly seeps through the gravel and into the sand beneath. Treatment of the effluent occurs during this process. Purification of the effluent occurs by 3 different processes. Aerobic microbes may assimilate nutrients in the effluent.

Filtration of solids is enabled by the sand. A chemical process also occurs in which contaminants attach to the sand grains and biological growth above the sand. Once treated, the wastewater collects in an under drain. The wastewater is then discharged by a pump into a drain field which consists of trenches filled with gravel. A network of pipes is also found in this gravel. The wastewater is slowly discharged from the pipes into the gravel. It then trickles into the soil below. A replacement drain field must always be situated in the vicinity of the current drain field. The replacement field must be the same size as the current field. It becomes operational when the existing field can no longer be used.

Maintenance of Sand Filter Systems

It is best not to place impermeable materials over the septic system and replacement field. Concrete, brick, plastic and other similar materials hinder evaporation. They also constrict supply of air into the soil which hinders effective treatment of effluent. Equally, you should not park your vehicle or store heavy equipment over the system. A cover of grass can be maintained over the septic system.

Inspect your septic system periodically. If you notice odors or wet areas on the surface, get professional help. System overload results in lower efficiency. It is best to practice water conservation and balance water utilization throughout the week. It also helps if you divert water from roofs, patios or driveway away from the septic system. Avoid use of sprinkler systems in the septic system area. It is a good idea to mound the soil around the septic system area. This improves water runoff.