SAND FILTER & PRESSURE BED SYSTEMS
Maintaining your Onsite septic system is very important. Having the knowledge as to what you may do to care for the system, when the system needs attention, and when you are due for service; is the key to a healthy Onsite septic system.
Intermittent Sand Filters (I.S.F) vary size and design as well. The I.S.F may be installed either above ground or in ground. the I.S.F is categorized as a Treatment level 1 unit due to being a single pass media filer which restricts it to not being able to complete the process of denitrification. Sizing of the onsite system are calculated by the number of bedrooms in a dwelling. With this in mind a large factor in the approval process of an Onsite system are the following; the soils type, where the properties water table level is, and at what depth the restrictive layer(s) are in the soils; will determine the trench depth and lengths allowed in the installation of your Septic drain field laterals.
Intermittent Sand Filter Septic Systems are similar to the ones of an ATT Septic Systems. Trench depths on a these systems (including cap & fill systems) vary between 10" to 24". In very rare cases you may find the inistal trench depth shallower with a cap & fill (may be seen on repairs). With that said in other cases you may find the laterals trench bottom deeper than 24" due to not having to use an ATT system for soils types etc, but rather for the lack of space to install a complete standard system.
Depending on several factors (which vary from site-to-site), your system may or may not require you to have an effluent pump (lift station) to discharge effluent from the tank(s) to the drain field.
Absorption system types vary from Low pressure distribution (shallow trenches) and standard trenches. Shallow trenches are an equal distribution type of dispersal system. Dispersal types on the standard trenches range from equal distribution via Pump feed (from the tank to distribution box to laterals), equal distribution via pump feed from tank(s) to a hydro-splitter which feeds the laterals equally via gravity, or serial distribution via pump feed (which is Pumped from the tank(s) to the first drop box and there after gravity takes over to fed the laterals).
It is more common to see a Ground Water Interceptor (G.W.I) on a ATT system install than you would on a standard system install (but not always the case). Ground water interceptors aid in re-directing not only surface water runoff but also the movement of water underground in the absorption facility area. The tight line running from the G.W.I to the discharge point needs to bedded correctly to ensure no bellies in the pipe and the discharge takes place onto a rip-wrap (to prevent erosion) from the water flow being re-directed by the G.W.I.
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