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Title: Interim guidelines on the ranges of enteric organism decay rates (T90s) under different marine conditions
Author: P. Gale
Document Type: Monograph
An important consideration in the design of long sea sewage outfalls is the rate at which faecal bacteria and viruses decay once discharged into the marine aquatic environment. A quantitative measure of the mortality rate typically used as a design parameter is the T90 value, which is the time taken for 90% of the organisms to be inactivated. Unfortunately, the T90 value for a particular bacterium or virus in a marine environment is influenced by a multitude of factors which include the intensity of solar radiation, the amount of sediment suspended in the water, the temperature, and the levels of nutrients and predators. Furthermore, the method used to perform the mortality experiment also affects the T90 value. Thus, it is difficult to assign an exact T90 value to a particular organism in a marine environment. In this report the ranges of T90 values obtained from analysis of mortality experiments reported in the literature are presented. Various indicator and pathogenic bacteria and enteric viruses in different marine conditions are covered.
Publisher: National Rivers Authority
Publication Date: 1990
Publication Place: Bristol
Subject Keywords: Water pollutionSewageMarine environmentBacterial monitoringViruses
Extent: 9
Total file downloads: 260

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