Effluent sewer
Effluent sewers also currently serve fewer people than septic systems, which also use septic tanks, but simply dispose of the effluent by draining it into a leach field. About one quarter of United States homes dispose of their wastewater with septic tanks. However, effluent sewers are being looked at as a sewage treatment solution in areas where gravity sewer systems are not well-suited or when the high capital cost to build a gravity system is prohibitive. Areas that are less than ideal for gravity systems include areas that are large, but extremely flat and areas that require long-distance pumping, such as where homes are widely spread out or when several small villages or towns connect their sewage systems so that a centralized plant can be built.
Bon Secours Mother and Baby Home
Corless's original research noted that the site was also the location of a septic tank when overlaid with maps of the period of use as a workhouse. The 2017 report by an Expert Technical Group, commissioned by the Department of Children and Youth Affairs, confirmed that the vault was a sewage tank after reviewing historical records and conducting a magnetometer survey; it concluded, "The combination of an institutional boarding home and commingled interments of juvenile remains in a sewage treatment system is a unique situation, with no directly comparable domestic or international cases."