The subsurface drip wastewater disposal system is actually a modified underground absorption system. It's a shallow, pressure-dosed, slow-rate method of disposal for treated wastewater. Drip technology has been used in the past mostly for agricultural irrigation purposes. Only recently has the technology been used for wastewater disposal.
The subsurface drip theory is simple, but the technology is advanced. This system doses the soil at a shallow level, at a very slow rate, and with very small amounts of water, but it uses several hundred or thousand dosing points equally. It would be comparable to using a dropper to distribute a small volume of water over several square feet of soil surface. The total effect to any one spot of the soil surface should not be noticeable.
How does a subsurface drip system work? This system can be used to help water shrubbery or yards, an option that may appeal to many homeowners. Also, the subsurface drip system can be placed in areas with trees by routing the drip tubing around the trees. On many parcels of property with limited space and clay textures or high seasonal water tables, this might be the only wastewater system that will work properly.
In a drip system, the wastewater from the home must first undergo aerobic treatment. . The effluent is discharged from the treatment unit and collected in a tank, then stored until enough is available to pump into the drip lines. B e f o re the effluent is pumped into the drip lines, it's filtered by some means to remove any solids that can cause a clogging problem in the drip lines. Once filtered, the effluent is pressurized and sent to the subsurface drip field, then allowed to slowly drip into the soil.
The drip field consists of polyethylene tubing installed in parallel rows at least two feet apart. The tubing has emitters installed at two-foot intervals that distribute the effluent into the soil very slowly. A means is also provided to backwash the drip lines and filter to prevent clogging.
For more information, please follow the links to Netafim, USA.
Netafim Wastewater Reuse and Drip Design Guide
Wastewater Drip Dispersal Maintenance Checklist