Haw. Code R. § tit. 11, subtit. 1, ch. 20, app I
Table C - List of Small Systems Conpliance Technologies for Radionuclides And Limitations to Use
Unit technologies | Limitations (see footnotes) | Operator skill level required1 | Raw water quality range and considerations1 | |
1. | Ion exchange (IE) | (a) | Intermediate | All ground waters |
2. | Point of Use (POU)2 (IE) | (b) | Basic | All ground waters |
3. | Reverse osmosis (RO) | (c) | Advanced | Surface waters usually require prefiltration |
4. | POU2 (RO) | (b) | Basic | Surface waters usually require prefiltration |
5. | Lime softening | (d) | Advanced | All waters |
6. | Green sand filtration | (e) | Basic | |
7. | Co-precipitation with Barium sulfate | (f) | Intermediate to Advanced | Ground water with suitable water quality |
8. | Electroidalysis/electrodialysis reversal | Basic to intermediate | All ground waters | |
9. | Pre-formed hydrous Manganese oxide filtration | (g) | Intermediate | All ground waters |
10. | Activated alumina | (a), (h) | Advanced | All ground waters, competing anion concentrations may affect regeneration frequency |
11. | Enhanced coagulation/filtration | (i) | Advanced | Can treat a wide range of water qualities |
1. National Research Council (NRC), Safe Water from Every Tap: Improving Water Service to Small Communities. National Academy Press, Washington, D.C. 1997
2. A POU, or "point-of-use" technology is a treatment device installed at a single tap used for the purpose of reducing contaminants in drinking water at that one tap.
POU devices are typically installed at the kitchen tap. See the April 21, 2000 NODA for more details.
Limitations Footnotes: Technologies for Radionuclides
a The regeneration solution contains high concentrations of the contaminantions. Disposal options should be carefully considered before choosing this technology.
b When POU devices are used for compliance, programs for long-term operation, maintenance, and monitoring must be provided by water utility to ensure proper performance.
c Reject water disposal options should be carefully considered before choosing the technology. See other RO limitations described in the SWTR Compliance Technologies Table.
d The combination of variable source water quality and the complexity of the water chemistry involved may make this technology too complex for small surface water systems.
e Removal efficiencies can vary depending on water quality.
f The technology may be very limited in application to small systems. Since the process requires static mixing, detention basins, and filtration, it is most applicable to systems with sufficiently high sulfate levels that already have a suitable filtration treatment train in place.
g This technology is most applicable to small systems that already have filtration in place.
h Handling of chemicals required during regeneration and pH adjustment may be too difficult for small systems without an adequately trained operator.
i Assumes modification to a coagulation/filtration process already in place.
Haw. Code R. tit. 11, subtit. 1, ch. 20, app I