Alternate Filtration - Cryptosporidium
List of approved bag and cartridge alternative filtration devices for meeting the requirements of the Surface Water Treatment Rule, including the 2-log removal requirement for Cryptosporidium contained in the Long Term 1 Enhanced Surface Water Treatment Rule (LT1).
This is a listing of filtration devices that are not currently listed as acceptable under the National Sanitation Foundation (NSF) criteria for Cyst Reduction (NSF Standard 53). These filters are approved based on third-party testing to NSF standards, with results that indicate compliance with NSF cyst reduction criteria.
Caution: The proposed use of these devices requires careful and thorough consideration of the characteristics of the raw water which will affect its service life. Physical water quality parameters such as suspended solids, algae density, turbidity, particle size and relative numbers, and Microscopic Particulate Analysis (MPA) test results are useful data. During the design process, the effect of dynamic operating variables, such as water hammer, air burps, startup and shutdown procedures, backwash events, or changes in flow rates should be considered. In addition, biological growth (slime) on the membranes may be a fouling factor. The need for pretreatment is an essential part of the design analysis.
Some of these devices provide extremely effective particulate removal, sometimes in excess of regulatory requirements. Removing particles smaller than giardia (less than 5 microns) or cryptosporidium (less than 3 microns) may significantly reduce expected service life. These devices are approved for use based on site specific conditions during the plan review process for a Public Water System (PWS) to meet the requirements of the Surface Water Treatment Rule (SWTR).
A filtration device listed with NSF International (NSF) as conforming to ANSI/NSF Standard 53 for Cyst Reduction is acceptable. Other products tested according to this standard may be acceptable based on supporting documentation. These devices must still be approved by DEC during the plan review process for site conditions unique to a PWS. Installation according to manufacturer's recommendations is usually required for design variables such as flow rate and allowable differential pressure. If a filter does not meet NSF standard 53, but is shown to remove at least 99 percent of giardia and cryptosporidium sized particles, it must also show the filter and housing are suitable for contact with potable water. Products or materials conforming to NSF standard 61 (or equivalent) meet this requirement. Note: NSF standard 53 includes materials requirements similar to those of NSF Standard 61.
This listing is not a guarantee of the availability of the product. Please contact DEC to get the most current listing and contact the manufacturer directly to obtain the most current product information. These products may not be available from vendors in Alaska . Please consult with your local water treatment vendor regarding these devices.
The Strainrite Companies, Inc.
Filter: AQUA-RITE HPM99-CCX-2SR (bag filter)
Harmsco Municipal Filtration Systems
Filter: HC/170-LT2 (cartridge filter)
Last updated 4/23/2013
For information contact:
Scott Forgue, P.E.
phone: 907-262-3417; fax 907-262-2294
Alaska Department of Environmental Conservation
Division of Environmental Health
Drinking Water Program
43335 Kalifornsky Beach Rd. Ste. 11, Soldotna, AK 99669