Recirculating Sand Filter Septic System
Recirculating sand filter (RSF) systems were first developed in Massachusetts in the earlier 1900's as an alternative to the conventional septic system. Homeowners install an RSF drip system because they want additional processing and removal of nitrogen from their septic tank effluent. This could be because of high ground or because they are close to a body of water with a high water table. Sand filter systems can be built above or below the ground.
Recirculating sand filter vs conventional septic system
A sand filter system is often chosen because of the above-average treatment of pathogens and nutrients. This makes them good septic systems for properties near a body of water or that have high water tables/ groundwater. Compared to conventional septic systems they cost more to install and maintain.
Recirculating Sand Filter System Process
Step 1 - Septic tank
This step is the same as other septic systems. Depending on the size of the house and occupants, will determine the size of the tank needed. Some counties have specific tank size or volume requirements for RSF systems like Masachuttuses requires a minimum tank volume of 1500 gallons. The septic systems tank handles the on-site wastewater treatment. It is recommended that an effluent filter be added to the outlet pipe to filter the wastewater effluent and reduce the solids flowing into the pipes.
Step 2 - Pump chamber
Once the effluent has exited the septic tank, it flows using gravity into the pump chamber which is the distribution system of the septic system. Depending on the design of the system, the pump chamber can have either a single purpose or a dual purpose.
Single-purpose - The pump chamber pumps the effluent to the bed and the treated wastewater exits to the leach field.
Dual-purpose - The first purpose is as a pump chamber. It stores the effluent wastewater from the tank and houses the return sand filter effluent so it can be pumped to the top of the sand filter. There can also be a recirculation tank that does this part of the process instead of the pump chamber. The second of the dual-purpose pump chamber is to remove excess nitrogen, a nutrient that needs to be reduced before flowing to the leach field. This is usually done by anaerobic bacteria in the pump chamber and is converted into nitrogen gas.
Step 3 - Sand filter
The septic tank effluent is pumped from the pump chamber to the sand filter. A sand filter is often made of PVC-lined or a concrete box filled with sand. Wastewater effluent is pumped at low pressure from the pump chamber to the top of the sand filter bed. The effluent filters through the sand media and the septic effluent is either returned to the pump chamber for nitrogen removal and to be recirculated or it exits the sand filter bed to the drain field.
Installing or replacing a Recirculating Sand Filter System
If you are considering having a Recirculating Sand Filter System installed on your property, your system has reached the end of its life, or you need your system repaired - get a free quote from a local septic tank company now.