Potable and Non-potable water

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.[21]

Unplanned Indirect Potable Use[22] 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-, SO42-, K+ and Na+, which are not removed by conventional sewage treatment.


[edit] Possible Improvements in treatment
As world populations require both more clean water and better ways to dispose of wastewater, the demand for water reclamation will increase. Future success in water reuse will depend on whether this can be done without adverse effects on human health and the environment.

In the United States, reclaimed waste water is generally treated to secondary level when used for irrigation, but there are questions about the adequacy of that treatment. Some leading scientists in the main water society, AWWA, have long believed that secondary treatment is insufficient to protect people against pathogens, and recommend adding at least membrane filtration, reverse osmosis, ozonation, or other advanced treatments for irrigation water.[23]

Seepage of nitrogen and phosphorus into ground and surface water is also becoming a serious problem, and will probably lead to at least tertiary treatment of reclaimed to remove nutrients in future.[24] Even using secondary treatment, water quality can be improved. Testing for pathogens using Polymer Chain Reaction (PCR) instead of older culturing techniques, and changing the discredited fecal coloform "indicator organism" standard would be improvements. In a large study [25] treatment plants showed that they could significantly reduce the numbers of parasites in effluent, just by making adjustments to the currently used process. But, even using the best of current technology, risk of spreading drug resistance in the environment through wastewater effluent, would remain. Some scientists have suggested that there need to be basic changes in treatment, such as using bacteria to degrade waste based on nitrogen (urine) and not just carbonaceous (fecal) waste, saying that this would greatly enhance effectiveness of treatment.[26] Currently designed plants do not deal well with contaminants in solution (e.g. pharmaceuticals). "Dewatering" solids is a major problem. Some wastes could be disposed of without mixing them with water to begin with. In an interesting innovation, solids (sludge) could be removed before entering digesters and burned into a gas that could be used to run engines.[27] Emerging disinfection technologies include ultrasound, pulse arc electrohydrolic discharge, and bank filtration.[28] Another issue is concern about weakened mandates for pretreatment of industrial wastes before they are made part of the municipal waste stream.[5] Some also believe that hospitals should treat their own wastes. The safety of drinking reclaimed water which has been given advanced treatment and blended with other waters, remains controversial.


[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. [29] [30]

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,[31] with Irvine Ranch Water District as one of the leading developers. They were the first district to approve the use of 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. Two major capital cities in Australia, Adelaide and Brisbane, have already committed to adding reclaimed effluent to their dwindling dams. 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. Goulbourn, Canberra, Newcastle, and Regional Victoria, Australia are already considering building a reclaimed effluent process.

According to a EU-funded study, "Europe and the Mediterranean countries are lagging behind" California, Japan, and 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."[32]


[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, transportation, and waste disposal problems. 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. [33] Some systems now exist which directly use greywater from a sink to flush a toilet[34] or even combine the two into one piece of furniture[35].

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
London,United Kingdom
Singapore (where it is branded as NEWater)
Payson, AZ[36]
The Torreele project in the Veurne coastal region of Belgium, which began operating in 2002 [32]
Virginia Occoquan Reservoir - The Upper Occoquan Sewage Authority plant discharges its highly treated output to supply roughly 20% of the inflow into the Occoquan Reservoir, which provides drinking water used by the Fairfax County Water Authority - one of the three major water providers in the Washington, D.C. metropolitan area.

[edit] Non-potable use
Sydney, Australia[37]
Tucson, Arizona[38]
Clark County, Nevada[39]
Clearwater, Florida[40]
St. Petersburg, Florida[41]
San Diego, California (San Diego County)[42]
Contra Costa County, California[43]
Austin, TX[44]
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.[45][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) [46][47]
Newcastle, New South Wales, Australia (proposed for non-potable use).[48]
Canberra, Australian Capital Territory, Australia (proposed in January 2007 as a backup source of potable water)[49]
Los Angeles, California - By 2019, the Los Angeles Department of Water and Power will build a plant to replenish their groundwater aquifer with purified water[50] in order to deal with the shortage of rain and snow fall, restricted water imports and local groundwater contamination [51].

[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] See also
Water portal
Dual piping
Greywater
NEWater
Sewage treatment
Water conservation
Water filtration
Water Pinch
Water management hierarchy
Cost effective minimum water network

[edit] References
1.^ NEWater FAQ, accessed 8 Jan 2007.
2.^ P.F.Cooper,2001, Decentralized Sanitation and Reuse, Chapt.2, IWA Publishing, London,UK.
3.^ 33 Usc 1251 seq., 1972, Federal Water Pollution Control Act, Enacted by Congress.
4.^ John Stauber, Sheldon Rampton, Toxic Sludge is Good for You..., Common courage Press.
5.^ a b Sierra Club Fact Sheet
6.^ Gennaccaro, McLaughlin, Betancourt, Huffman and Rose, Infectious Cryptosporidium parvum Oocysts in Final Reclaimed Effluent, Dept Marine Science, U of South Florida, St Petersburg, Florida.
7.^ EPA Guidelines for Water Reuse, (1996)
8.^ 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
9.^ 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.
10.^ 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.
11.^ Amy Pruden, 2006, Antibiotic Resistance genes as emerging contaminants, Studies in Northern Colorado, Environmental Science Technology 40, 7445-7450
12.^ Edo Mcgowan, (2008) The Watchers.US/edo_politics-reclaimed-water.html-74k
13.^ Maria Burke (2004),UK to tackle Endocrine Disruptors in Wastewater, Technology News, Sept 1,2004.
14.^ US Dept of Agriculture, 2005 Report
15.^ From the Toilet to the Tap, Australian Broadcasting Corporation 9 November 2006
16.^ Committee on the Viablility of Augmenting Drinking Water Supplies with Reclaimed water, 1998, Issues in Potable Reuse, National Research Council
17.^ Timothy LaPara, Sara Firl, 2006, The Importance of Municipal Sewage Treatment in the spread of Antibiotic resistance, 106th General Meeting of the American Society for Microbiology.
18.^ James D. Oliver, 2005, The Viable but Nonculturable State in Bacteria, J. of Microbiology p.93-100.
19.^ Valerie J. Harwood, Audry D. Levine, Troy M. Scott, Joan G. Rose, 2005,Validity of the Indicator Organism Paradign for Pathogen Reduction in Reclaimed Water and Public Health Protection, Applied and Environmental Microbiology, Vol.71.
20.^ Tsai, Kan-Jen (2008). "Bacterial Heavy Metal Resistance". Osaka Biology. http://www.bio.sci.Osaka-u.ac.jp/initiative2006pdf/TsaiLectSum.pdf. Retrieved on 2008-05-11.
21.^ Public Utilities Board, NEWater FAQ, accessed 8 Jan 2007.
22.^ Public Utilities Board, Overseas Experiences, accessed 24 April 2007.
23.^ Fred Lee PhD, President American Water Works Association, Reuse Conference, 1996
24.^ Harvey H. Harper PhD., 2008, Good intentions gone awry?, 27th International Symposium of North American Lake Management Society, Orlando Florida
25.^ Joan Rose, et al, 2004 Reduction of pathogens, indicator bacteria, alternative indicators by wastewater treatment and reclamation process, WERF
26.^ Peter Maier PhD, Is Sewage Properly Treated?, Peter Maier.Net
27.^ Ken Stedman, 2007, Micromedia Filtration Inc helps Gold Village Come Clean, Press Release
28.^ Jess C. Brown and Andrew Salveson, 2007, Emerging Disinfection Technologies Florida Resources Journal, July 6.
29.^ Rules and Regulations for Reclaimed Water. City of San Diego. 31 January 2007.
30.^ Purple Rain Education Program. Pasco County, Florida. 31 January 2007.
31.^ UF Professor: Drought Highlights Value Of Reused Water. University of Florida News. May 24, 2000.
32.^ a b "Reuse of water in the EU and the Mediterranean", by Bill McCann, Water 21, Journal of the International Water Association, April 2008, p. 42-44, quoting the Aquarec project
33.^ Grey Water SydneyWater.com.au 31 January 2007.
34.^ WaterSaver Technologies Aqus Uses Sink Greywater for Toilet. Treehugger.com. October 7, 2006. Retrieved May 22, 2007.
35.^ Toilet Lid Sink. Gaiam. Retrieved May 22, 2007.
36.^ Green Valley Park Lakes Groundwater Recharge Project.
37.^ Sydney Water Recycling Projects
38.^ Reclaimed Water
39.^ Water Reclamation
40.^ Making the Connections: Reclaimed and Drinking Water Supplies
41.^ Water Systems Maintenance Mission Statement
42.^ Recycled Water
43.^ Delta Diablo Sanitation District, Eastern Contra Costa County
44.^ Austin Water Utility
45.^ Application form for access to Recycled Water (Caboolture)
46.^ Beattie scraps water poll amid 'Armageddon situation'. ABC News Online 28 January 2007.
47.^ Beattie defends recycled water against "scare mongers". ABC News Online 26 January 2007.
48.^ Recycling plant brings region closer to being drought proof. ABC News 19 July 2006.
49.^ Recycled water a step closer for Canberrans. ABC News Online 31 January 2007.
50.^ [1]
51.^ [2]

[edit] External links
Waterwise A not-for-profit, non-governmental organization dedicated to promoting the wise use of water
WateReuse A nonprofit organization whose mission is to advance the beneficial and efficient use of water resources using reclamation, recycling, reuse and desalination
Retrieved from "http://en.wikipedia.org/wiki/Reclaimed_water"
Categories: Water supply | Sewerage