Raw water

Source: Wikipedia, the free encyclopedia.

Raw water is water found in the environment that has not been

ground water, water from infiltration wells, and water from bodies like lakes and rivers
.

Raw water is generally unsafe for human consumption due to the presence of contaminants. A major health problem in some developing countries is use of raw water for drinking and cooking.[1]

Without treatment, raw water can be used for

waste water
.

Raw water flushing is a method of water conservation
where raw water is used for flush toilets.

Composition

The composition of raw water is naturally variable, but commonly contains one or more of the following significant contaminants, in the form of dissolved ions, particles and living organisms:[3]

Other, less common, contaminants of raw water include:

These contaminants can be harmful to humans if they drink raw water containing them, or if the water is not treated properly before consumption. The contaminants can also have an effect on the local ecosystem. For example, endocrine disrupting chemicals can have harmful effects on fish populations living in natural

sustainable water supply alternatives.[8][9]

Treatment

Main article: Water treatment
Water treatment plant of Bragança, Portugal

Raw water can be used for many purposes, such as

contaminants, raw water must be treated before it is allowed for human consumption or industrial use.[11]
There are several steps involved in the treatment of raw water, and different methods in which it can take place.

Reverse osmosis

radioactive particles can be removed with reverse osmosis alone.[4][12] This efficiency has made reverse osmosis the primary method of water purification
, often being used in combination with other methods, as a final treatment. A downside to reverse osmosis is that the removing of most minerals from water can have negative effects on its taste.[12] Minerals are sometimes added to drinking water that was already filtered to improve its taste.

Conventional pre-treatment

The conventional treatment method for water purification is a complex, multistage process that was used for many years.

fluoridation. This process is often used as a pre-treatment method while another processes, such as reverse osmosis, is used for the final treatment.[10]
A disadvantage of this method is its use of chemicals, such as
flocculents, hydrogen peroxide, lime, and chlorine for the filtration process.[10] These chemicals could be dangerous if used incorrectly or if they remained in the water after complete treatment. This requires special precautions, and each step of the process has to be controlled to achieve an overall optimal performance.[10] The need for a complex control system for conventional treatment can result in it being financially costly.[10]
This has led to the development of alternative pre-treatment and treatment methods for raw water.

Ultrafiltration

Drinking water treatment of 300 m3/h using ultrafiltration in Grundmühle waterworks (Germany)

chemicals, and final product free of viruses and microorganisms
.

Biofilm pre-treatment and Bio-diatomite Dynamic Membrane Reactor

The

diatomite particles to purify water.[14] These methods are under development in China as part of addressing the country's pollution
problems.

Turbidity

Turbid Water

hazy water seems due to suspended particles. The more suspended particles, the higher the turbidity. Turbidity is used to visually measure water quality, being most common in unfiltered raw water.[15]
High amounts of turbidity in raw water can occur due to:[15]

  • Increased flow due to heavy rain fall
  • Spring turnover of water masses
  • Bank erosion
  • Sediment resuspension in shallow areas
  • Temporary increase from the more turbid areas

Turbidity and health concerns

During high turbidity peaks,

morbidity caused by these illnesses.[9]

Controlling turbidity

Controlling the land surrounding raw water reservoirs and other sources is key to reducing turbidity. Areas of high sediment resuspension and erosion need attending regularly, and screens and other devices are needed to catch suspended particles. Screens that trap particles and debris must be cleaned consistently. Flushing out water pumps should be done when demand is lowest. This gives time for the water to settle, and decrease turbidity before is it needed in high amounts. "Turbidity reduction is best achieved when the water is run through a series of chemical and physical treatment methods before reaching the filter".[17]

Waterside of Saint Lawrence River near Kamouraska

Raw water dieting

See also: Raw foodism

Around 2017, untreated spring water, described as "naturally probiotic" raw water, became a commercial product distributed through health food shops, but experts have raised public health concerns about the possible occurrence of harmful bacteria, viruses, and parasites such as

anti-vaccination movement.[22] One raw water business in the United States has even claimed that methods used by bottled and spring water producers could change the molecular structure of water.[23][24]

The fad was mocked on The Daily Show in April 2018 in a segment that included an interview with Marion Nestle.[25][26]

See also

References

  1. PMID 8779590
    .
  2. ^ Perth W.A. (2016) What is Raw Water?. Vintage Road Haulage. http://www.vintageroadhaulage.com.au/faq/what-is-raw-water/
  3. ^ Safe Drinking Water Committee (1980), "Raw water quality", Drinking Water and Health, vol. 2, National Academies, pp. 7 et seq
  4. ^ a b Manu, A., Santhanakrishnan, V., Rajaram, S., & Ravi, P. M. (2014). Concentration of natural radionuclides in raw water and packaged drinking water and the effect of water treatment. Journal of Environmental Radioactivity, 138, 456-459
  5. ^ Happonen, M., Koivusalo, H., Malve, O., Perkola, N., Juntunen, J., & Huttula, T. (2016). Contamination risk of raw drinking water caused by PFOA sources along a river reach in south-western finland. Science of the Total Environment, 541, 74-82
  6. ^ Falconer, I. R. (2006). Are Endocrine Disrupting Compounds a Health Risk in Drinking Water? International Journal of Environmental Research and Public Health, 3(2), 180–184
  7. ^ Mills, L. J., & Chichester, C. (2005). Review of evidence: Are endocrine-disrupting chemicals in the aquatic environment impacting fish populations? Science of the Total Environment, 343(1–3), 1-34
  8. ^ Dewettinck T, van Houtte E, Geenens D, van Hege K, Verstraete W. HACCP (Hazard analysis and critical control points) to guarantee safe water reuse and drinking water production. A case study. Water Sci. Technol. 2001; 43: 31–38
  9. ^ a b Rodriguez, C., Van Buynder, P., Lugg, R., Blair, P., Devine, B., Cook, A., & Weinstein, P. (2009). Indirect Potable Reuse: A Sustainable Water Supply Alternative. International Journal of Environmental Research and Public Health, 6(3), 1174–1209
  10. ^ a b c d e f g h Clever, M., Jordt, F., Knauf, R., Räbiger, N., Rüdebusch, M., & Hilker-Scheibel, R. (2000). Process water production from river water by ultrafiltration and reverse osmosis. Desalination, 131(1–3), 325-336
  11. ^ a b Bertone, E., Stewart, R. A., Zhang, H., & O'Halloran, K. (2016). Hybrid water treatment cost prediction model for raw water intake optimization. Environmental Modelling & Software, 75, 230-242
  12. ^ a b c Vingerhoeds, M. H., Nijenhuis-de Vries, M. A., Ruepert, N., van der Laan, H., Bredie, W. L. P., & Kremer, S. (2016). Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation. Water Research, 94, 42-51
  13. ^ a b Yang, G., Feng, L., Wang, S., Zhou, J., Guo, C., Xia, T., Sun, W., Jiang, Y., Sun, X., Cao, Lian., Xu, X., Zhu, L. (2015). Potential risk and control strategy of biofilm pretreatment process treating raw water. Bioresource Technology, 198, 456-463
  14. ^ Chu, H., Cao, D., Dong, B., & Qiang, Z. (2010). Bio-diatomite dynamic membrane reactor for micro-polluted surface water treatment. Water Research, 44(5), 1573-1579
  15. ^ a b Gauthier, V., Barbeau, B., Tremblay, G., Millette, R., & Bernier, A. (2003). Impact of raw water turbidity fluctuations on drinking water quality in a distribution system. Journal of Environmental Engineering and Science, 2(4), 281-291
  16. ^ Schwartz, J., Levin, R., & Goldstein, R. (2000). Drinking water turbidity and gastrointestinal illness in the elderly of Philadelphia. Journal of Epidemiology and Community h, 54(1), 45–51
  17. ^ Satterfield, Z. (2006). Turbidity Control. Tech Brief, 6(2), 1-4
  18. Sydney Morning Herald
    , 4 January 2018.
  19. ^ Mosia,Lebohang. "Why is there such a thirst among influencers for ‘raw water’?", Independent Online, 10 November 2022.
  20. ^ Turton, William. "The Juicero founder is really into raw water", Vice News, 7 March 2018.
  21. ^ Mole, Beth. "Meet “raw” water—ludicrously priced unfiltered water with random bacteria", Ars Technica, 2018.
  22. Fortune.com
    , 31 December 2017.
  23. ^ Bever, Lindsey (4 January 2018). "'Raw water' is the latest health craze. Here's why drinking it may be a bad idea". Washington Post. Retrieved 4 January 2018.
  24. ^ Bowles, Nellie (29 December 2017). "Unfiltered Fervor: The Rush to Get Off the Water Grid". The New York Times.
  25. ^ "Video: A Deep Dive into the "Raw Water" Craze - The Daily Show with Trevor Noah (Video Clip)". Comedy Central. 18 April 2018.
  26. ^ "A Deep Dive Into The "Raw Water" Craze — The Daily Show (YouTube)". 30 March 2022.

Additional sources

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