Safe potable water is a luxury that is generally unavailable to the majority of rural and suburban populations of developing, underdeveloped, and often developed countries. Important considerations in the development and maintenance of safe water supplies is the availability and use of efficient, inexpensive, and appropriate technology for removing microbial hazards, parasites, and toxicants. The Manz intermittent slow sand filter was known to be user friendly, small enough to fit into the smallest kitchen, and could remove up to 97% of the fecal coliforms present in the raw water before treatment by the Manz filter. This filter was evaluated for its ability to remove parasitic cysts and toxicants as well as bacteria. Using two different filters and two different water supplies our results indicated that the intermittent slow sand filter could remove 83+% total heterotrophic bacterial populations, 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× environmental pollution levels. Methodology details are provided in the paper. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 217–225, 1999

To predict the performance of UV systems for disinfecting wastewater a full scale UV system was subjected to changes in wastewater quality. The effect of changes in the UV transmission and suspended solids on fecal coliforms was measured. The level of UV transmission and suspended solids which can be treated is dependent upon the disinfection limit. There was no relationship between the UV transmission and the suspended solids and the degree of photoreactivation. An antibiotic labeled Escherichia coli was irradiated with the UV system and then observed in glass bottles and in the receiving stream for photoreactivation. Photoreactivation was observed in the glass bottles but not in the receiving stream. In the natural environment photoreactivation may not be important

In trying to establish the extent and degree of impact of point and nonpoint source contaminants on riverine systems, it is important to know the implications of the data obtained from various sampling points in a riverine system. Spatial variability between water and/or sediment samples collected in close approximation at the same sites was assessed by the battery of tests approach. In these samples there appeared to be no consistent relationship between sediment structure, microbial population, and toxicant concentrations. Furthermore the ATP‐TOX System and Mutatox tests were the most responsive tests in all types of samples. Since sediments with their bound contaminants may be an important factor in this data interpretation, different methods for releasing and concentrating the sediment bound contaminants were evaluated. The results and implications of these results are described.

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