High‐Quality Water Production and Viral Disease

Abstract

Improvements in analytical methods have created a wide range between the ideal water and the quality acceptable under the U.S. Public Health Service (USPHS) Drinking Water Standards, which define the borderline between a tolerable water and one that is unacceptable. Within this range certain water treatment plants consistently produce water of superior quality, but others barely meet the minimum levels. This article examines the reasons for the characteristic differences in results obtained, and explores their relation to viral disease incidence. The article includes a discussion by Richard L. Woodward of the Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio. He makes the point that, far from quarreling with Hudson's principal thesis, much more information and careful study are needed before the significance of water in endemic infectious hepatitis can be determined.

Measurement of Low Turbidities

“…Optical turbidity, T, refers to the light scattered per cell path length, b, in the equation: (1) in which 1 is the intensity of transmitted light and 10 is the intensity of light incident upon a suspension having negligible absorption of light. This equation may be transformed into the more useful relationship:…”

Getting your money's worth from filtration

“…In 1962 Bean recommended 0.1 turbidity unit as a quality goal for drinking water.34Hudson reviewed water quality and viral disease data in 1962 and concluded that for plants treating polluted water, low virus disease rates occurred in cities where water treatment plant operators aimed to produce a superior product rather than a tolerable water. 35 Hudson stated that producing high-quality water involved a number of criteria, including filtered water turbidity, plate count, coliform determination, and thorough chlorination.…”

Relation of Raw‐Water Quality to Treatment Plant Design

“…Hudson 13 has compared the incidence of infectious hepatitis in cities served by various types of water supplies. He found that morbidity rates were lower in cities served by ground water and by unfiltered surface supplies than in cities using filtered supplies from either lightly or heavily polluted sources.…”