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.
Principles of intelligent urbanism
There is an appropriate balance to be found somewhere on the line between wasteful low-density individual systems and over-capitalized mega systems. Individual septic tanks and water bores servicing individual households in low-density fragmented layouts, allow the use of filtered greywater for free irrigation of gardens, but, if not maintained, can cause a local pollution of subterranean aquifer systems. The bores can dramatically lower ground water levels especially during droughts. The vantage of septic tanks an bores is to be managed by the very users, at no cost for the community.
Alternatively, large-scale, citywide sewerage systems and regional water supply systems are capital intensive and prone to management and maintenance dysfunction, if not corruption or extortion by private companies. Operating costs, user fees and cost recovery expenses are high. There is a balance wherein medium-scale systems, covering compact communities, utilize modern technology, without the pitfalls of large-scale infrastructure systems. This principle of urbanism promotes the middle path with regard to public infrastructure, facilities, services and amenities.