Conservancy tank
An underground tank, which stores sewage, consists of blackwater (toilet waste) and greywater (kitchen, shower, sink, and laundry waste) until the time of emptying. It must be watertight to prevent the leakage of foul water or the ingress of groundwater. They may be constructed in a variety of materials including brick or concrete, but modern ones are more commonly made from glass-reinforced plastics, polythene or steel and have a minimum capacity of 18, 000 litres. Conservancy tanks must be emptied frequently. Leakage is more common in very old ones built of brick and concrete. The structure may have deteriorated allowing ingress of groundwater and leakage of foul effluent that will cause pollution and odor. The connection between the inlet pipe and the tank may develop a leak.
| Advantages | Disadvantages |
|---|---|
| Advantages 1. Flexible and adaptable to a wide variety of individual household waste disposal requirements. |
Disadvantages 1. Continuous emptying required |
Contents
Operation and maintenance
Regular emptying of conservancy tank contents should be done when the wastewater occupy 2/3 of the tank’s capacity. Emptying frequency depending on tank’s capacity and amount of people. Normally done once every 1-2 months.
Applying conditions
Satisfactory and acceptable facility for excreta disposal and other liquid wastes from individual houses, cluster of houses, apartments, and institutions (schools).
Costs
Cost of introduction: Text
Cost of maintainance: Text