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PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYS, E. COLI, AND BACILLUS SPORES IN DRINKING WATER: PALL CORPORATION MICROZA MICROFILTRATION 3-INCH UNIT, MODEL 4UFD40004-45; AT MANCHESTER, NEW HAMPSHIRE
Citation:
Arenberg, M. PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYS, E. COLI, AND BACILLUS SPORES IN DRINKING WATER: PALL CORPORATION MICROZA MICROFILTRATION 3-INCH UNIT, MODEL 4UFD40004-45; AT MANCHESTER, NEW HAMPSHIRE. U.S. Environmental Protection Agency, Washington, DC.
Description:
Verification testing of the Pall Corporation Microza MF S;ystem equipped with a 3-inch filter module, took place between April 30 and August 9, 2000 in Manchester, NH. The source water was drawn from a canal connected to Lake Massabesic, the public reservoir that serves the Town of Manchester. The source water Contained low alkalinity (3.5 mg/l), with turbidity levels that averaged 0.8 NTU and ranged between 0.07 amd 3.8 NTU. The source water had a close to neutral pH at 6.4 (ranged from 5.5 to 7.2), and a TOC concentration in mg/l of between 4.68 and 5.09 with an average of 4.83. The average feed water temperature was 19 C. Large blooms of algae, diatoms, and zooplankton occurred in the raw water during the testing. Tese blooms usually do not occur in such abundance at this time of year. Use of a source water with high concentrations of algae and/or iron bacteria in the feed water is not typical for MF technology and presented a worst case scenario fdd water and a severe use condition for the Pall unit.
The test unit produced an average of 2.3 gpm of filtrate when operating at an average recovery rate of 90%. The average transmembrane pressure and special flux during the verification study were 14.22 psi and 3.60 gfd/psi, respectively. Microbial seeding challenges involving Cryptosporidium oocysts E. coli, and Bacillus spores were performed on May 3rd, June 21st and August 9th, 2000. The first test on May 3rd was performed at the beginning of E. coli, and Bacillus spores were performed on May 3rd, June 21st and August 9th, 2000. The first test on May 3rd was performed at the beginning of a filter run on a new clean membrane to assess the performance on a clean membrane. The other two challenge tests were performed when the transmembrane pressure (TMP) approached its 30 psi limit to assess the performance of the membrane under stress from maximum allowed differentia pressure. As a result of the three Cryptosporidium oocyst seeding studies, the membrane demonstrated 6.6, 4.1, and 5.6 log 10 removals of Cryptosporidium oocysts, respectively. Cryptosporidium oocysts were not detected in the filtrate. As a result of three E. coli challenges the membrane demonstrated 6,7,3.9, 6.5 log 10 removal of E. coli, respectively. The results of two of the Bacillus spore challenges (the results of the Bacillus spore seeding on June 21st were inconclusive) indicate a 4.0 and 7.1 log 10 removal of Bacillus spores, respectively. Bacillus spores were not detected in the filtrate during two of the challenges. Turbidity levels were reduced 96% on average. The algae in the source water reduced run times by at least 75% as estimated by the manufacturer, who anticipated run times on the order of 30 days between cleanings. The frequency of membrane fouling indicates that some sort of pre-filter would be necessary in order to achieve longer run times at this location. For additional information on operation and maintenance of the system on a cleaner water source, refer to a previous ETV Report (#00/09/EPADW395) for testing of this system at a site in Pittsburgh, PA.