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Membrane Challenge Studies

Public water systems with membrane filtration systems for removing Cryptosporidium and Giardia must receive approval from the TCEQ to evaluate each membrane’s ability to remove pathogens. The filtration systems impacted by this requirement are those that were installed or replaced after April 1, 2012.

Public water systems must conduct challenge testing for membrane filtration systems that are installed to remove Cryptosporidium and Giardia. These tests evaluate how efficiently each membrane model removes pathogens and allows the TCEQ to establish a log removal value (LRVC-Test).

 Membrane manufacturers must provide a non-destructive performance test (NDPT) and quality control release value (QCRV). The NDPT and QCRV help verify that all manufactured membrane models that were not subject to challenge testing in the past will achieve at least the same log removal level as more current membrane models that were challenge-tested.

Public water systems with membrane filtration systems will be approved for a removal-credit based on the lower of the LRVC-Test and the log removal value that can be verified through direct integrity testing (LRVDIT).

Challenge studies for the following membrane models for Cryptosporidium and Giardia removal have been reviewed and approved by the TCEQ:

 The following table shows the current membrane systems with their TCEQ-approved credit values for pathogen removal:

Make and Model 

Log Removal 

Log Removal 

 Date(s) Approved 
by TCEQ 

 Dow UF-SFD2880   3.76  3.76  August 3, 2012


 ZeeWeed 500D 

 6.2, deposition mode 

 6.1, feed-and-bleed mode 

 January 27, 2014 

 Harmsco HC/170-LT2 

 Cartridge Filter 


 3.0, Bin 1 

 3.1, Bin 2, Bin 3, Bin 4 

 (3.1 each cartridge filter, 

 6.7 maximum for two in series) 

 January 18, 2013 

 Koch Targa II UF 

 Cartridge Filter 

 4.6  June 26, 2013 
 Pall Microza 620A MF 


 March 20, 2013 

 Siemens Memcor 

 L10N and L20N 

 UF Cartridges 


 April 8, 2013 
 Siemens S10N UF   5.03   October 23, 2013 

Any manufacturer seeking to distribute a membrane in the state of Texas must send the challenge study for the particular model to TCEQ for review and approval prior to installation. Challenge studies may be mailed to the following address:

Texas Commission on Environmental Quality
Technical Review & Oversight Team (MC-159)
PO Box 13087
Austin TX 78711-3087

For more information about these requirements see Title 30, Texas Administrative Code, Section 290.42(g)(3). Exit the TCEQ

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