Sanlexicon Q - R
Content Table
Recycling and re-use of water
The recycling and re-use of wastewater or polluted groundwater can be economically and environmentally beneficial and practicable in many settings. However, these water sources require careful management. The two main re-use techniques are:
- blending, which involves the mixing of marginal quality water with good quality water to reduce the concentration of pollutants; and
- treatment, which involves either high-cost treatment works or low-cost systems such as wetlands, soil aquifer systems or stabilization ponds to remove pathogens and undesirable trace elements.
Reduced-cost sewerage scheme
The design and layout of these schemes can be divided into three broad groups:
- simplified sewerage,
- condominial sewerage and
- sewered interceptor tanks,
all of which have much in common. The sewers are generally small bore and shallowly laid through back yards, gardens and passages etc, where conventional sewage systems would cause too much disruption and be too expensive. High levels of community ownership are essential to ensure proper maintenance. Interceptor tanks can be placed at each house to take off the solid content of the waste and allow the liquid element to pass down a drain thereby allowing smaller, cheaper diameter pipe to be used.
See Also:
Retention time
The time it takes for wastewater to flow from inlet to outlet through a wastewater treatment system (e.g. septic tank, oxidation ponds etc.). The retention time is directly related to the quality of treatment, as bacteria and other contaminants die off over time.
