Restoring streams and wetlands
In recent years many wastewater treatment plants have been upgraded to meet increasingly stringent environmental requirements for discharge to receiving waters. The effect of moving from treated effluent quality discharges to recycled water quality discharges is assisting in the preservation and enhancement of the aquatic environment in many locations.
Examples of stream restoration include:
- San Luis Obispo, California: Recycled water from the treatment plant is used for industrial and landcape irrigation needs, but is also used to meet regulatory minimum discharge requirements to maintain environment flows for endangered fish species in San Luis Obispo Creek downstream of the city. The recycled water discharges provide improved in-stream environmental conditions in summer.
- Japan: There has been extensive use of recycled water to restore degraded urban streams. In Tokyo, 43,300 m3/d of recycled water has been used to restore flows in the Nobidome and Tamagawajousi channels (Ohgaki & Sato, 1991). In Nagoya, 7400m3/d of recycled water has been used to restore flows in the Arako River (Ogawa, 2001).
- Sydney, Australia: A scheme will be constructed to supply up to 50,000m3/d of recycled water to provide environmental flows in the Hawkesbury river downstream of the main water storage. The scheme will make additional freshwater available to supply Sydney.