On-Site Wastewater Treatment
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3 |
Reduces the amount and cost of potable water and sanitary sewer discharge, reduces energy cost and related greenhouse gas (GHG) emissions for water treatment, and protects the water quality of host countries |
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18 months for design and construction and six months for system testing and commissioning (Cx) |
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Design and installation of a WWT system; regular maintenance and ongoing testing |
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FAC, BPO |
In addition to providing environmental benefit to the local area, reuse of treated wastewater for irrigation or toilet flushing can reduce the utility costs incurred, reduce maintenance required for off-site discharge, and reduce demand on municipal and well water systems.
Pumps and blowers in traditional WWT facilities consume energy, and fugitive emissions are released during the processing of waste. Natural treatment systems, such as constructed wetlands, are preferable to traditional facilities when sufficient site area is available and the system will be serving a small population.
Constructed wetlands can be less expensive than traditional WWT facilities, support biodiversity, and provide site aesthetics. Successfully constructed wetland design includes consideration of site geology and location within the watershed; review of native plant and animal species; and development of a long-term inspection, monitoring, and maintenance plan.
Due to the complexity of design, installation, and operational impact, WWT systems are best utilized when:
- Sites are not connected to municipal WWT systems.
- Local governments do not treat wastewater to WHO standards.
- Demand for irrigation or potable water exceeds municipal supply.
Consider opportunities for reducing discharge, or for upgrading WWT plants to provide effluent that meets reuse standards:
- Undertake water conservation measures to reduce discharge (see Water: Efficient Fixtures, Irrigation, and Rainwater Harvesting).
- Identify minor WWT plant upgrades to provide a net positive environmental benefit, such as eliminating potable water for irrigation.
- Consider treatment and reclamation options for graywater or blackwater, such as biofiltration, filters, disinfection, or other technologies. Consider both site and economic constraints.
U.S. Embassy Ouagadougou treats wastewater using constructed wetlands
