Reclaimed water

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Reclaimed water, sometimes called recycled water, is former wastewater (sewage) that has been treated to remove solids and certain impurities, and then allowed to recharge the aquifer rather than being discharged to surface water. This recharging is often done by using the treated wastewater for irrigation. In most locations, it is only intended to be used for nonpotable uses, such as irrigation, dust control, and fire suppression. In some locations (not in the United States), utilities claim that it is treated to be cleaner than standard drinking water,^[1] and is used indirectly for drinking.

Contents 1 History 2 Benefits 3 Potential problems in use for irrigation 4 Suitable for drinking? 5 Treated Wastewater Contaminates Drinking Water 6 Distribution and demand 7 Worldwide acceptance 8 Other alternatives 9 Some locations using reclaimed water 9.1 Indirect potable use 9.2 Non-potable use 9.3 Proposed 10 Enterprises 11 Maximum Water Recovery 12 Lack of Testing and Standards 13 See also 14 References 15 External links

[edit] History

Los Angeles County's sanitation districts have provided treated wastewater for landscape irrigation in parks and golf courses since 1929.

The first reclaimed water facility in California was built at San Francisco's Golden Gate Park in 1932. In Southern California, Irvine Ranch Water District and Orange County Water District are becoming the leaders in reclaimed water through their Green Acres Project.

[edit] Benefits

The costs involved with reclaimed water typically exceed those of standard potable water in many regions of the world, where a fresh water supply is plentiful. However, reclaimed water is usually sold to citizens at a cheaper rate to encourage its use.

Using reclaimed water for non-potable use saves potable water for drinking, since less potable water will be used for non-potable uses.

It sometimes contains higher levels of nutrients such as nitrogen, phosphorus and oxygen which may somewhat help fertilize plants when used for irrigation.^{[citation needed]}

[edit] Potential problems in use for irrigation

Recent studies support long standing concerns about possible public health effects of reclaimed water. It has been known for some time that treated waste water effluent, or reclaimed water, contains pathogens that can be transferred to people. In 1997, the EPA Handbook warned,"(Viable) bacteria from reclaimed water in sprinklers can travel more than 1000 feet in the air."<EPA Guidelines for Water Reuse, (1996)> As far back as 1984, researchers concluded that disinfection by chlorination, an important part of wastewater treatment, initially lowers the total number of sewage related bacteria, but may substantially increase the proportions of antibiotic resistant, potentially pathogenic organisms. <GE Murray, RS Tobin, B Junkins,DJ Kushner,(1984)Effect of Chlorination on antibiotic resistance profiles of sewage-related bacteria, Appl Environ Microbiol. July 1998:48(1): 73-74>

More recently, Chang(2007) reported that staphyloccus aureus bacteria(responsible for MRSA)become more virulent and

drug resistant after chlorination.<Matthew Wook Chang, Freshteh Toghrol, William Bentley,Toxicogenomic Response to Chlorination Includes Induction of Major Virulence Genes in Staphylococcus aureus,Environ. Sci. Technol., 41(21)7570-7575.> A large study in 2006 confirms that microbes, inactivated but not killed by treatment, can regrow in retention ponds and pipes, becoming a major source of the spread of multi drug resistant pathogens in the environment. <Timothy Lapara, Sara Firl,(2006)The Importance of Municipal Sewage Treatment in the Spread of Antibiotic resistance,100th General Meeting of the American Society for Microbiology, May 21-25, 2006. Orlando Fl.> There is also concern in the industry about organic chemicals, including endocrine disruptors in wastewater <Maria Burke(2004),UK to tackle Endocrine Disruptors in Wastewater, Technology News, Sept 1,2004.> In 2005,US Dept of Agriculture reported:"Overall, the environmental and public health impacts of irrigation with reclaimed sewage effluent and the potential degradation of underlying groundwater are largely unknown",<US Dept of Agriculture, 2005 Report>

[edit] Suitable for drinking?

In most locations, reclaimed water is not directly mixed with potable (drinking) water for several reasons:

• Utilities providing reclaimed water for nonpotable uses do not treat the water to drinking water standards.
• Varying amounts of pathogens, pharmaceutical chemicals (e.g., hormones from female hormonal contraception) and other trace chemicals are able to pass through the treatment and filtering process, potentially causing danger to humans. Modern technologies such as reverse osmosis may help to somewhat overcome this problem. An experiment by the University of New South Wales reportedly showed a reverse osmosis system removed ethinylestradiol and paracetamol from the wastewater, even at 1000 times the expected ppm.^[2]
• Drinking water standards were developed for natural ground water, and are not appropriate for identifying contaminants in reclaimed water. In addition to pathogens, and organic and endocrine disrupting chemicals, a large number of compounds may be present in reclaimed water. They cannot all be tested for,and there is a paucity of toxicity information on many of the compounds. <Committee on the Viablility of Augmenting Drinking Water Supplies with Reclaimed water,1998, Issues in Potable Reuse National Research Council>Notindustry (talk) 20:15, 16 May 2008 (UTC)

Because of this, state regulatory agencies do not allow reclaimed water to be used for drinking, bathing, or filling swimming pools. They also warn those who use reclaimed water for irrigation to place a sign on their property warning people not to drink from the irrigation system, and to not use it directly on fruits or vegetables.

[edit] Treated Wastewater Contaminates Drinking Water

During the processing of reclaimed (recycled)water, genetic fragments can be released from microbes when their cell walls are disrupted. These fragments are not alive, and not affected by disinfectants, such as chlorine. This intact genetic material can transfer both virulence and drug resistance to living microorganisms in water or soil. Amy Pruden(2006)demonstrates that such genetic fragments pass through sewerwater reclamation plants into rivers, and into drinking water sources.<Amy Pruden,2006,Antibiotic Resistance Genes as emerging Contaminants:Studies in Northern ColoradoEnvironmental Science Technology, 40,7445-7450

Some municipalities are now investigating Planned Indirect Potable Use (IPU) of reclaimed water. For example, reclaimed water may be pumped into reservoirs where it will mix with (and be diluted by) rainwater. This mixture of rainwater and reclaimed water could then be treated again, and finally used as drinking water. This technique may also be referred to as groundwater recharging or reservoir augmentation. Singapore plans to increase the amount of reclaimed water in their reservoirs from 1% to 2.5% by 2011.^[1]

Unplanned Indirect Potable Use^[3] has existed even before the introduction of reclaimed water. Many cities already use water from rivers that contain effluent discharged from upstream sewage treatment plants. 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. This phenomenon is also observed in the United States, where the Mississippi River serves as both the destination of sewage treatment plant effluent and the source of potable water. Research conducted in the 1960s by the London Metropolitan Water Board demonstrated that the maximum extent of recycling water is about 11 times before the taste of water induces nausea in sensitive individuals. This is caused by the build up of inorganic ions such as Cl^-, SO4^2-, K⁺ and Na⁺, which are not removed by conventional sewage treatment.

[edit] Distribution and demand

Reclaimed water is often distributed with a dual piping network that keeps reclaimed water pipes completely separate from potable water pipes. In the United States, reclaimed water is always distributed in lavender (light purple) pipes to distinguish it from potable water. ^{[4] [5]}

In many cities using reclaimed water, it is now in such demand that consumers are only allowed to use it on assigned days. Some cities that previously offered unlimited reclaimed water at a flat rate are now beginning to charge citizens by the amount they use.^{[citation needed]}

[edit] Worldwide acceptance

The leaders in use of reclaimed water in the U.S. are Florida and California,^[6] with Irvine Ranch Water District as one of the leading developers. They were the first district to approve the use reclaimed water for in-building piping and use in flushing toilets.

As Australia continues to battle the 7-10 year drought, nationwide, reclaimed effluent is becoming a popular option. Already three major and capital cities in Australia, have committed to adding reclaimed effluent to their dwindling dams, including Adelaide, Brisbane and indirectly Sydney. Brisbane has been seen as a leader in this trend, and other cities and towns will review the 'Western Corridor Recycled Water Project' once completed. Already Goulbourn, Canberra, Newcastle, and Regional Victoria, Australia are also considering building a reclaimed effluent process.

According to a EU-funded study "Europe and the Mediterranean countries are lagging behind" California, Japan or Australia "in the extent to which reuse is being taken up." According to the study "the concept (of reuse) is difficult for the regulators and wider public to understand and accept."^[7]

[edit] Other alternatives

In urban areas where climate change has threatened long-term water security and reduced rainfall over catchment areas, using reclaimed water for indirect potable use may be superior to other water supply augmentation methods. One other commonly-used option is seawater desalination. Recycling wastewater and desalinating seawater may have many of the same disadvantages, including high costs of water treatment, infrastructure construction, and water transportation. Although the best option varies from region to region, desalination is often superior economically, as reclaimed water usually requires a dual piping network, often with additional storage tanks, when used for nonpotable use.

A less elaborate alternative to reclaimed water is a greywater system. Greywater is wastewater that has been used in sinks, baths, showers, or washing machines, but does not contain sewage (see blackwater). In a home system, treated or untreated greywater may be used to flush toilets or for irrigation. ^[8] Some systems now exist which directly use greywater from a sink to flush a toilet^[9] or even combine the two into one piece of furniture^[10].

Perhaps the simplest option is a rainwater harvesting system. Although there are concerns about the quality of rainwater in urban areas, due to air pollution and acid rain, many systems exist now to use untreated rainwater for nonpotable uses or treated rainwater for direct potable use. There are also concerns about rainwater harvesting systems reducing the amount of run-off entering natural bodies of water.

[edit] Some locations using reclaimed water

[edit] Indirect potable use

• Singapore (where it is branded as NEWater)
• Payson, AZ^[11]
• The Torreele project in the Veurne coastal region of Belgium, which began operating in 2002 ^[7]

[edit] Non-potable use

Austin, TX http://www.ci.austin.tx.us/wri/

• Sydney, Australia^[12]
• Tucson, Arizona^[13]
• Clark County, Nevada^[14]
• Clearwater, Florida^[15]
• St. Petersburg, Florida^[16]
• San Diego, California (San Diego County)^[17]
• Contra Costa County, California^[18]
• Caboolture and Maroochy (South East Queensland, Australia) LGA's currently provide Reclaimed water for industrial use (primarily capital works). Users must apply for a key to be able to access the compounds in which the outlets are located.^{[19][citation needed]}

[edit] Proposed

In some places, reclaimed water has been proposed for either potable or non-potable use:

• South East Queensland, Australia (planned for potable use as of late 2008) ^[20][21]
• Newcastle, New South Wales, Australia (proposed for non-potable use).^[22]
• Canberra, Australian Capital Territory, Australia (proposed in January 2007 as a backup source of potable water)^[23]

[edit] Enterprises

• Brac Systems - Canada

[edit] Maximum Water Recovery

There are various techniques that have been developed by researchers for maximum water reuse/reclamation/recovery strategies such as water pinch analysis. The techniques helps a user to target the minimum freshwater consumption and wastewater target. It also helps in designing the network that achieves the target. This provides a benchmark to be used by users in improving their water systems.

[edit] Lack of Testing and Standards

Reclaimed water is not regulated by the EPA but by the states, using standards formulated decades ago. Newer information shows serious public health concerns about pathogens in the water.^[24] Many pathogens cannot be detected by currently used tests.^[25] Recent literature also questions the validity of testing for "indicator organisms" instead of pathogens.^[26] Nor do present standards consider interactions of heavy metals and pharmaceuticals which may foster the development of drug resistant pathogens in waters derived from sewage.^[27]

[edit] See also

• Dual piping
• Greywater
• NEWater
• Sewage treatment
• Water conservation
• Water filtration
• Water Pinch
• Water management hierarchy
• Cost effective minimum water network

[edit] References

[edit] External links

• Waterwise A not-for-profit, non-governmental organization dedicated to promoting the wise use of water