Water Recycling - A global perspective
| More about recycling in WA | |
|---|---|
 | Kwinana Water Reclamation Plant - supplying recycled water to businesses |
| | Mc Gillivray Oval, Floreat - irrigated with recycled water |
| | Albany treefarm - irrigated with recycled water |
| | Wastewater disposal and recycling - opens Water Forever website |
| | Alternative water supplies for land developers - opens Water Forever website |
 | State Water Plan 2007 - Published March 2007 |
| | State Water Strategy - Published February 2003 |
International schemes
Unplanned potable re-use
Many major towns and cities around the world recycle water to add to their drinking supplies including Brisbane, Singapore and in the USA: Orange County; suburbs of Washington D.C; Northern Virginia; Clayton County; and Georgia.
The Groundwater Replenishment Trial follows the approach used in California where treated wastewater undergoes additional treatment and is added to aquifers before use in drinking water supplies. The treatment processes to be used in the Trial are most similar to those used in Singapore.
In various states of America, including California, Colorado, Florida, Northern Virginia, Texas and Washington, trials have been undertaken since the 1970s and have proven to be highly successful. These trials have resulted in a number of full schemes being developed.
Other Australian states including Canberra and Queensland are investigating recycled water for drinking; however these proposals involve adding the water to their dams (their major drinking water source), rather than into groundwater.
The key difference between these proposals and Water Corporation’s Groundwater Replenishment Trial is in where the water goes after its is treated to be as safe as drinking water, in this case to deep confined groundwater reserves rather than a dam more directly linked to the public water supply.
National schemes
Western Corridor Recycled Water Project, Queensland Australia
http://www.westerncorridor.com.au
Source: Domestic and industrial wastewater.
Treatment: Micro-filtration, reverse osmosis and ultraviolet disinfection with hydrogen peroxide disinfection (advanced oxidation).
Final uses: Direct supply to power stations. Added to Wivenhoe Dam when supplies are low.
In 2009 the Queensland Government completed a $9 billion Water Grid to treat and supply recycled water to southeast Queensland. This water is used for nearby power stations and will be added to Wivenhoe Dam, Brisbane and surrounds' major water source, when combined dam levels fall below 40%.
International schemes
NEWater, Singapore
http://www.pub.gov.sg/NEWater/
Source: Domestic and industrial wastewater.
Treatment: Ultra-filtration/ micro-filtration and reverse osmosis, followed by ultraviolet disinfection.
Final uses: Direct supply to industry. Added to reservoirs used for drinking supplies.
NEWater is highly treated recycled water that has been strongly endorsed as a safe and sustainable source of water exceeding the drinking water standards of the World Health Organisation (WHO). NEWater was subjected to 20,000 tests over two years before it was endorsed by the WHO.
Singapore has been developing recycled water plants since the late 1990s. Approximately 11 megalitres a day of water is added to a reservoir then further treated as part of Singapore's normal drinking water treatment system. This water currently provides approximately 1% of Singapore's daily requirements, and the volume of recycled water will increase to 2.5% by 2011.
Goreangab Water Reclamation Plant, Namibia
Source: Domestic and business wastewater only. Industrial wastewater is treated separately.
Treatment: Powdered activated carbon, acid, polymers, pre-ozonation, coagulation/flocculation, dissolved air flotation, rapid sand/anthracite filtration, ozonation, biological-activated carbon filtration/adsorption, granular-activated carbon filtration/adsorption, membrane ultra-filtration and chlorination/stabilisation.
Final uses: Directly added to the city's drinking water system, aquifer recharge, irrigation.
Although today's technology is much further advanced, the town of Windhoek in Namibia has been successfully using water purification for drinking purposes since the 1960s. Recycling can now directly provide 35% of the daily requirements of the City. In the very near future, all excess reclaimed water will be used to artificially recharge the Windhoek aquifer.
Groundwater Replenishment System, California USA
http://www.gwrsystem.com/about/overview.html
Source: Domestic and industrial wastewater.
Treatment: Micro-filtration, reverse osmosis and ultraviolet disinfection with hydrogen peroxide disinfection (also known as advanced oxidation).
Final uses: Added to groundwater to prevent saltwater intrusion and drawn up for drinking supplies.
Orange County, California has recycled water for drinking since early 1976. Currently approximately 57 megalitres per day of recycled water is blended with groundwater and then pumped it into the groundwater system to replenish drinking water supplies and prevent saltwater intrusion. In 2007 the scheme was expanded to pump 265 megalitres per day into aquifers which supply up to 50% of Orange County's water.
The process used today incorporates a higher level of treatment than the original water recycling scheme, known as Water Factory 21, which consisted of lime clarification, re-carbonation, granular-activated carbon, reverse osmosis and chlorine disinfection.
http://www.ocwd.com/_html/wf21.htm
Montebello Forebay Groundwater Recharge Project, California, USA
http://www.lacsd.org/about/wastewater_facilities/
Source: Domestic and industrial wastewater.
Treatment: Soil aquifer treatment via spreading basins into the Rio Hondo and San Gabriel Coastal Spreading Grounds
Final uses: Added to the groundwater basin used for drinking supplies or irrigation.
The Whittier Narrows Water Reclamation Plant is the source water for the longest running groundwater recharge project in the United States. It provides treatment for 170 ML of used water per day, making up 35 percent of the total recharge to the groundwater basin. The plant serves a population of approximately 150,000 people and replenishes the basin with water for 3.7 million people. Virtually all of the purified water is reused as groundwater recharge into the Rio Hondo and San Gabriel Coastal Spreading Grounds or for irrigation at an adjacent nursery.
The Montebello Forebay Groundwater Recharge Project is important because of its long duration and many health studies which were completed. The health effect studies reported that there is no discernible difference between the health of people who have been drinking the water produced by the project and the health of those who have not.
Scottsdale Water Campus, Scottsdale, Arizona, USA
http://www.scottsdaleaz.gov/water/conservation/qa.asp
Source: Domestic and industrial wastewater.
Treatment: low-pressure membrane filtration, thin-film wells. Groundwater recharge uses micro-filtration and reverse osmosis.
Final uses: Irrigation of golf courses and added to drinking water aquifers in Winter months.
The Water Campus contains a water treatment plant, a water reclamation plant and an advanced water treatment facility. The water reclamation facility currently produces water principally for golf course irrigation. In the winter when irrigation needs are reduced, the water undergoes advanced purification (microfiltration and reverse osmosis) before discharge into the drinking water aquifer.
Aurora Water Prairie Waters Project, Colorado USA
Source: Domestic and industrial wastewater.
Treatment: Infiltration through soil, chemical softening, advanced ultraviolet oxidation, filtration and granulised activated carbon adsorption.
Final uses: Directly added to the city’s drinking water system.
Treated wastewater disposed of to the Colorado River filters through the riverbank into groundwater. The water is then extracted and piped to infiltration basins where it seeps through layers of soil into the aquifer. The water is recovered 2-5 years later and treated before being distributed to customers. Once complete in late 2010, the Prairie Waters Project will increase Aurora's water supply by 20 percent; delivering up to 10 thousand acre-feet (about 3.3 billion gallons) of water per year.
Upper Occoquan Sewage Authority Water Reclamation Plant, Fairfax County, Virginia, USA
Source: Domestic and industrial wastewater.
Treatment: High pH lime clarification, two-stage re-carbonation, media filtration, granular-activated carbon, ion exchange and chlorination
Final uses: Added to the Occoquan Reservoir drinking water source.
Recycled water is added to the Occoquan Reservoir which is the source of water for more than 1 million people, representing 7% of the total flow into the catchment.
Clayton County Water Authority Land Application System and Wetlands, Georgia, USA
Source: Domestic and industrial wastewater.
Treatment: wastewater treatment (grit screening and removal, biological treatment, clarification) then disposal to constructed wetlands for infiltration into groundwater.
Final uses: Augments the drinking water supply.
Recycled water is pumped to a series of treatment wetlands which form a "living filter" before it passes into reservoirs. Water from the wetlands eventually drains to storage reservoirs in the area to augment the drinking water supply.
Hueco Bolson Recharge Project, El Paso, Texas, USA
http://www.epwu.org/reclaimed_water/r_water.html
Source: Domestic and industrial wastewater.
Treatment: Advanced treatment using a ten-step process (powdered-activated carbon [PAC], lime clarification, recarbonation and granular media). Ozone is used in the disinfection process.
Final uses: Recharges the groundwater aquifer from which the drinking water supply is drawn.
The Hueco Bolson Recharge Project started operation in 1985 and treats up to 7.5 megalitres a day of used water to drinking water standards for recharge into the Hueco Bolson aquifer. The aquifer provides about 40% of the water for El Paso and the surrounding area and 100% of the water needs of the cities of Ciudad Juarez in Mexico and Fort Bliss in Texas however it receives a very limited natural recharge. The processing facility utilises a ten-step process to produce water which meets US Environmental Protection Agency drinking water standards for recharge.
F. Wayne Hill Water Resource Center, Lawrenceville, Georgia, USA
Source: Domestic and industrial wastewater.
Treatment: Chemical coagulation, granular media filtration, carbon adsorption, membrane filtration and ozone disinfection, in addition to conventional secondary treatment and biological nutrient removal
Final uses: Added to Lake Lanier, a major drinking water source for the Atlanta area.
Water at the F. Wayne Hill Water Resource Center is treated and sent through a 32-kilometre pipeline to a discharge point in the Chattahoochee River. From 2009, the recycled water will be released into Lake Lanier, a major source of drinking water for the greater Atlanta area and a recreational body of water.
Langford Recycling Scheme in Essex & Suffolk, England
Source: Domestic and industrial wastewater
Treatment: Micro-filtration, ultraviolet disinfection
Final uses: Added to drinking water supplies.
The Longford Recycling Scheme, Essex was the first water purification project of its kind in Europe and commenced operation in 1997. The Scheme was the culmination of a project originally started in 1964 when a drought order allowed treated wastewater to be discharged to the river Chelmer instead of going to tide. This flow augmented the river and helped fill a reservoir. Research was then carried out to look into the feasibility of giving the waste water tertiary treatment so it would be of good enough quality to be permanently discharged to river to augment freshwater flow.
Treated wastewater is put into the purpose-built recycling plant for further tertiary treatment. The plant treats the water, removing phosphates, nitrates, ammonia, oestrogen and pathogens. Sludge is thickened through a dewatering process and then composted with straw off site and used agricultural food production. Finally, the recycled water is then discharged to augment the flow of the river Chelmer upstream of the Essex & Suffolk Water intakes.
Strict water quality control was put in place, including monitoring of viruses and oestrogens, and numerous studies have been done on the impact of the scheme on the environment and public health.
Recycled water is mixed with the water from the River Chelmer, which is abstracted at Langford, near Maldon, for Hanningfield reservoir refill where it is treated again before being put into drinking water supply. The scheme is associated with a population of up to 100,000.
Hampton Advanced Water Treatment, London, England
Source: Water from the River Thames, stormwater and industrial wastewater.
Treatment: Advanced water treatment utilising rapid gravity filters, ozone treatment and sand filters
Final uses: Added to public water supply reservoirs.
Thames Water draws water from the River Thames and pumps it to a variety of bank-side storage reservoirs. On arrival at Hampton, the stored water is fed into the Grand Junction Reservoir. This small reservoir is predominantly used to blend different source water and balance the flow into the works. The water is then filtered through primary rapid gravity filters. The water from the primary filters gravitates under the Grand Junction Reservoir and six pumps lift the water into the ozone plant, where it is subjected to ozone dosing before passing to slow sand filters. Ozone is the activated form of oxygen and the dosing helps to reduce pesticide concentrations. An added benefit of ozone is to reduce the concentration of dissolved organic compounds and thus decrease the amounts of chlorine needed for disinfection.
West Basin Water Recycling Program, El Segundo, California, USA
http://www.westbasin.org/education/water-information/water-recycling
Source: Domestic and industrial wastewater.
Treatment: Varies depending on needs of customer, includes micro-filtration, reverse osmosis, ultraviolet light and peroxide treatment.
Final uses: Added to groundwater to prevent salt water intrusion in drinking water supplies. The remainder is used for irrigation and industrial use.
The West Basin Water Recycling Facility (WBWRF) is the largest recycled water plant of its type in the United States. The WBWRF produces six different qualities of water for different water applications, all of which meet the water quality requirements specified in the California Department of Health Services Water Recycling Criteria. One of these water products is recharged into the ground to act as a barrier against seawater intrusion, protect water quality and replenish the region’s drinking water.
Wulpen, Belgium
Source: Treated wastewater from the Wulpen Wastewater Treatment Plant.
Treatment: Low-pressure submerged membrane filtration followed by reverse osmosis.
Final uses: Added to groundwater to prevent salt water intrusion in drinking water supplies.
Wulpen is located on the coast of Belgium, near the border with France. Its water supply is from a groundwater basin which is recharged with recycled water to prevent seawater intrusion. Of the total drinking water demand in the area where Intercommunaal Waterbedrijf Veurne-Ambacht distributes water, 45% is fulfilled with recycled water.
Unplanned potable re-use
Many communities also drink recycled wastewater in what is called “unplanned potable re-use”. This happens where one community collects and treats its wastewater, the cleaned product of which is output to a river up-stream of another community using the same river as their main drinking water source.
There are many large towns on the River Thames upstream of London (Oxford, Reading, Swindon, Bracknell) that discharge their treated sewage into the river, which is used to supply London with water downstream. The same happens in the United States, where the Mississippi River serves as both the destination of sewage treatment plant effluent and the source of potable water.
In Australia the Murray-Darling River System provides a number of examples of unplanned potable reuse. A number of farms, towns and cities draw a portion of their drinking water from and also discharge their wastewater into rivers and tributaries of the Murray-Darling System. Canberra, Albury and Wagga are examples of such cities. The Murray River is Adelaide’s primary drinking water supply source.
The difference between planned and unplanned potable reuse is in how they are designed and regulated. More stringent water quality and environmental requirements are in place for the planned wastewater recycling schemes such as groundwater replenishment in order to protect public health.
