Toxicant and parasite challenge of Manz intermittent slow sand filter

Safe potable water is a luxury that is generally unavailable to the majorit y of rural and suburban populations of developing, underdeveloped, and ofte n developed countries. important considerations in the development and main tenance of safe water supplies is the availability and use of efficient, in expensive, and appropriate technology for removing microbial hazards, paras ites, and toxicants. The Manz intermittent slow sand filter was known to be user friendly, small enough to fit into the smallest kitchen, and could re move up to 97% of the fecal coliforms present in the raw water before treat ment by the Manz filter. This filter was evaluated for its ability to remov e parasitic cysts and toxicants as well as bacteria. Using two different fi lters and two different water supplies our results indicated that the inter mittent slow sand filter could remove 83+% total heterotrophic bacterial po pulations, 100% of Giardia cysts, 99.98% of Cryptosporidium oocysts, and 50 -90% of organic and inorganic toxicants when administered in concentrations varying from 10- > 100 x environmental pollution levels. Methodology detai ls are provided in the paper. (C) 1999 by John Wiley & Sons, Inc.