Improving filtration of Cryptosporidium

Citation
K. Shaw et al., Improving filtration of Cryptosporidium, J AM WATER, 92(11), 2000, pp. 103
Citations number
30
Categorie Soggetti
Civil Engineering
Journal title
JOURNAL AMERICAN WATER WORKS ASSOCIATION
ISSN journal
0003150X → ACNP
Volume
92
Issue
11
Year of publication
2000
Database
ISI
SICI code
0003-150X(200011)92:11<103:IFOC>2.0.ZU;2-D
Abstract
Surface coating of hydrous iron aluminum oxide on Ottawa sand was investiga ted as a means of improving the removal of Cryptosporidium oocysts from wat er by filtration. Coating the sand increased the zeta potential from -40 to +45 mV at pH 7.0, increasing the potential for interaction with the negati vely charged (-25 mV at pH 7.0) Cryptosporidium oocysts. Water seeded with Cryptosporidium oocysts was passed through parallel columns of uncoated and coated sand at superficial velocities of 200-800 m/d (3.5-14 gpm/sq ft) an d column lengths of 100-400 mm (4-16 in.). In every trial, coated sand remo ved significantly more oocysts than uncoated sand. Filter coefficients of c oated sand were 2.9 times as high as those of uncoated sand, indicating tha t coating can significantly improve the removal of Cryptosporidium by granu lar media filters.