Septic tank
A septic tank is an underground chamber made of concrete, fiberglass or plastic through which domestic wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). Septic tank systems are a type of simple onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field which provides further treatment. However, groundwater pollution may occur and can be a problem.
Penrith railway station, Sydney
There is a water tank built in 1921, at the Sydney end of the station. It was built in the Newcastle PerWay Workshop and is one of 82 extant tanks in NSW but one of only three in Sydney (2009). The water tank was erected to serve the expanding traffic needs for the Penrith Station, an important locomotive service stop prior to the Blue Mountains ascent. It was part of a series of water tanks at Penrith, with smaller ones for older locomotives replaced by this tank, while other earlier ones were still used at the Loco Depot until it was phased out.