Kinetic degradation fluxion media

Kinetic degradation fluxion (KDF) is a high-purity brass water filtration product.[1] It was developed in 1984 and patented by Don Heskett in 1987.[2][3]

Description

The KDF 55 product is brass granules[4] with alloy proportions of 45% zinc and 55% copper. Similarly KDF 85 has 15%:85%.[5][6] Other KDF media are a fine metal wool, similar to steel wool.[7]

KDF media can remove chlorine, hydrogen sulfide, heavy metals, iron, and can reduce other inorganic contaminants.[7][8][9] The KDF filter media also inhibits the growth of algae, fungi, and bacteria.[8][10] For this reason, the effectiveness of activated carbon filters can be increased by combining them with KDF.[11]

In the KDF system, zinc acts as an anode and copper as a cathode in an electrolytic cell. Ionic contaminants are removed by electron exchange (a redox reaction), in which they become bonded to the surfaces of the media.[8] This redox reaction generates an electric potential of about 300mV, which is believed to be partly responsible for the antimicrobial effect.[8] The hydroxyl radicals formed during the redox reaction may also contribute to this effect.[7]

KDF media are used in municipal processing,[12] and medical and dental water treatment.[1][8][13] They are also used in treatment of industrial effluents.[12][14] They are used for home water filtration[7][15] and are often used (inline) in showers[16][17] because they remove chlorine[18] and remain effective at high temperatures.

Limitations

KDF filters do not remove organic chemicals, such as pesticides and disinfection byproducts, nor are they effective against parasitic cysts such as giardia or cryptosporidium.[13][19] KDF filters must be periodically backwashed with hot water to clean them,[1] making them both water and energy inefficient.[13][20] The dislodged pollutants can contaminate the water after the washing process.[13]

Assessments

The KDF system is certified to the NSF International Standard 61 for water treatment plant applications,[21] and the 2010 NSF standard for drinking water treatment units.[22] The United States Environmental Protection Agency finds that KDF media can remove mercury from contaminated water, but only at low concentrations, and recommends that for highly contaminated water other processes should be used.[23] A 2005 report by the US Department of Health and Human Services found that under normal operating conditions, a treatment of contaminated groundwater in the Cedar Brook area, consisting of KDF and activated carbon filter removed volatile organic compounds and mercury to levels compliant with the state drinking water standards.[24]

Due to its bactericidal action, KDF is considered by the EPA to be a "pesticidal device". However, Stanford physician Paul Auerbach recommends against using it as a sole means of germicidal water treatment. It is, furthermore, not included on his list of point-of-use disinfection methods for the elimination of protozoa or his recommendations for field disinfection.[7]

A 1995 United States Environmental Protection Agency report found that KDF systems were employed at approximately 20 US-based cooling towers in 1993. The report documented variable results. Some of the systems were ultimately discontinued because the medium was ineffective at controlling bacterial growth. Others that reported satisfactory results found the KDF system preferable to other systems because of comparatively safe waste products and a simpler maintenance cycle.[25]

In water containing high concentrations of copper, KDF media can remove some of the copper, and release zinc ions.[26] According to a report of New Zealand's Cawthron Institute, KDF systems are widely available in New Zealand for household water filtration, but although some units meet international standards for water treatment, others are unregulated. Moreover, they release zinc ions in the process of filtration which can lead to additional zinc in household wastewater, which is a concern especially when there are other environmental sources of metals.[4] Highly chlorinated water can result in a concentration of zinc that may be harmful to aquatic life, and publications of the American Water Works Association do not recommend the use of KDF media to treat chlorinated water that outflows to streams.[27]

See also

References

  1. 1 2 3 Jimmy Walker (2014). Decontamination in Hospitals and Healthcare. Woodhead Publishing. p. 194. ISBN 978-0857096579.
  2. ↑ Karl Weber (2012). Last Call at the Oasis: The Global Water Crisis and Where We Go from Here. PublicAffairs. pp. 181–. ISBN 978-1-61039-144-3.
  3. ↑ In Business, Volumes 13-14. JG Press. 1991. p. 16. In 1987, Haskett had patented a new fluid treatment technology that utilizes a copper-zinc alloy called KDF (Kinetic Degradation Fluxation) to remove chlorine, heavy metals and other inorganic contaminants...
  4. 1 2 Robina Ang (2012), Up the Pipe: A literature review of the leaching of copper and zinc from household plumbing systems (PDF), Cawthron Institute
  5. ↑ Brady, George S.; Clauser, Henry R.; Vaccari, John A. (2002). Materials Handbook: An encyclopedia for Managers, Technical Professionals, Purchasing and Production Managers, Technicians and Supervisors (15 ed.). McGraw-Hill Education. p. 17. ISBN 978-0071360760.
  6. ↑ "KDF 55 and 85 Process Media for Water Treatment". KDF Fluid Treatment, Inc. Retrieved 2016-06-30.
  7. 1 2 3 4 5 Paul Auerbach (2011). Wilderness Medicine: Expert Consult Premium Edition. Elsevier Health Sciences.
  8. 1 2 3 4 5 D.C. Coleman; M.J. O’Donnell; A.C. Shore; J. Swan; R.J. Russell (2007), "The role of manufacturers in reducing biofilms in dental chair waterlines", Journal of Dentistry, 35: 701–711
  9. ↑ James Hunt (2001). "Filtration media: Making the Right Choice: A Reference Guide for Dealers" (PDF). Water Conditioning & Purification.
  10. ↑ M.J.O’Donnell; M.Boyle; J.Swan; R.J.Russell; D.C.Coleman (2009), "A centralised, automated dental hospital water quality and biofilm management system using neutral Ecasol maintains dental unit waterline output at better than potable quality: A 2-year longitudinal study", Journal of Dentistry, 37: 748–762, doi:10.1016/j.jdent.2009.06.001
  11. ↑ Kemi Adeyeye (3 March 2014). Water Efficiency in Buildings: Theory and Practice. John Wiley & Sons. p. 196. ISBN 978-1-118-45657-6.
  12. 1 2 M Wethern; W Katzaras, "Reverse osmosis treatment of municipal sewage effluent for industrial use", Desalination, 102: 293–299, doi:10.1016/0011-9164(95)00066-B
  13. 1 2 3 4 "KDF Process Media". Lenntech. 2016. Archived from the original on 15 December 2015.
  14. ↑ Arianna Catenacci (2014), Heavy metal removal from water: characterization and applicability of unconventional media (PDF), Politecnico di Milano, Department of Civil and Environmental Engineering, p. 18: "A typical application of the KDF media in the treatment of industrial effluents pertains the removal of lead in the circuit board manufacturer industry: lead is removed for 94.4% thus enabling the recycle of water in a closed-loop rinse-down system. When filtered through KDF media, soluble lead cations are reduced to insoluble lead atoms, which are electroplated onto the surface of the media"
  15. ↑ Lono Kahuna Kupua A'o (1998). Don't Drink the Water (without Reading this Book): The Essential Guide to Our Contaminated Drinking Water and what You Can Do about it. Lotus Press.
  16. ↑ "KDF filter". Hyundai Wacortec. 2003. Retrieved 1 July 2016.
  17. ↑ Justin Thomas (1 January 2016). "The Best Shower Filter Of 2016". Retrieved 3 July 2016.
  18. ↑ "Aquashower" (PDF). Multipure.: " System tested and Certified by WQA against NSF/ANSI Standard 177 for the Reduction of Free Chlorine."
  19. ↑ "What is KDF?" (PDF). Aquasmart Technologies Inc. 2005.
  20. ↑ Maria Tikkanen (2001). Guidance Manual for Disposal of Chlorinated Water. American Water Works Association. p. 118.: "the capital cost of this system is slightly higher than that of chemical dechlorination systems".
  21. ↑ M.J.O’Donnell; M.Boyle; J.Swan; R.J.Russell; D.C.Coleman (2009), "A centralised, automated dental hospital water quality and biofilm management system using neutral Ecasol maintains dental unit waterline output at better than potable quality: A 2-year longitudinal study", Journal of Dentistry, 37: 748–762, doi:10.1016/j.jdent.2009.06.001: "The KDF-85 filter medium and the granular activated charcoal medium are certified to NSF International Standard 61 for water treatment plant applications." with a reference "NSF International Standard NSF/ANSI 61-2008. Drinking Water System Components – Health Effects."
  22. ↑ "NSF Certifications for KDF-55 & KDF-85". NSF International. 2010.
  23. ↑ National Risk Management Research Laboratory (1997), Aqueous mercury treatment, Environmental Protection Agency, Office of Research and Development, p. 5-1
  24. ↑ Agency for Toxic Substances and Disease Registry (7 July 2005). "Cedar Brook area groundwater contamination" (PDF). US Department of Health and Human Services.
  25. ↑ D. Bowman; J DeWaters; J Smith; S Snow; R Thomas (1995), Pollution prevention opportunity assessment: United States Norfolk Naval Air Station, pp. 4–15
  26. ↑ Arianna Catenacci (2014), Heavy metal removal from water: characterization and applicability of unconventional media (PDF), Politecnico di Milano, Department of Civil and Environmental Engineering, p. 18
  27. ↑ Maria Tikkanen (2001). Guidance Manual for Disposal of Chlorinated Water. American Water Works Association. p. 118.

Further reading

This article is issued from Wikipedia - version of the 10/29/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.