Effluent filters in the outlets of septic tanks keep particles larger than the filter’s slot, hole or opening from reaching the drainfield. These filters are designed for residential and commercial use, gravity flow applications and pressurized systems. But screening of large solids is just one of their jobs.Data from informal and unpublished studies yields many important clues about filters, heightening confidence in their use. For example, if the septic tank precedes a dosing tank containing a centrifugal effluent pump, an effluent filter can retain solids such as feminine hygiene products. An effluent pump will pass these solids through the pump
