The preferred means of directing a small systems effluent to a disposal area is by gravity flow.  The disposal area that the effluent is directed towards must be located to the downslope of the septic tank.  Gravity flow  is cost effective and eliminates the need for a mechanical device that has the potential to breakdown or become inoperative with a power outage.  There is however a disadvantage to gravity-flow because it does not provide equal distribution of effluent throughout the entire disposal area.

Pumping
Effluent pump systems are more expensive than gravity flow systems and require electricity and periodic maintenance.  Pumping is usually required when the suitable area for the disposal field is at a higher elevation than the building sewer and does not allow for gravity feed.   It can also be required when a system has been placed in or very near an area that has a seasonally high groundwater table.  Pumps raise the elevation of wastewater and allow it to enter a disposal area when gravity flow is not possible.

In systems that require pumping, an effluent pump is usually placed on the outlet side or within the septic tank to pump wastewater to the disposal field. Pumping stations should be sited in locations and at elevations which are not subject to either surface or groundwater infiltration.  If this is not possible, provisions should be made to prevent infiltration by sealing and/or intercepting and diverting the water source.

A sewage grinder pump or sewage ejector (solids handling pump) can be placed on the building sewer drain to pump raw sewage, which contains solids, to the septic tank. Occasionally, a sewage ejector or grinder pump is installed within the basement of a structure to avoid setback conflicts associated with septic tanks.  Care must be taken to utilize a pump, which has been properly sized, to accomplish the task of getting the wastewater to the desired elevation.  Selection of the correct pump requires knowledge of head and friction loss calculations (we can help with that here at Genest Precast).  Sewage grinder pumps are more costly than an effluent pump.  If conditions are right a "solids handling pump" may be substituted for cost-savings.