Sewer sediments: Preparation methods for enumerating bacteria

Abstract

In the UK, the Urban Pollution Management programme has contributed to extensive international research concerning solids associated with urban drainage systems.Since 1986, as part of the UPM programme, research undertaken at the Wastewater Technology Centre, University of Abertay Dundee, has focused primarily upon the characteristics and movement of solids and associated pollutants in combined sewer systems.These investigations have considered the behaviour of sediments and their attached pollutants during dry weather and storm flow conditions, and also the degree of pollutants associated with, and released from sewer sediments during periods of increasing sediment bed shear stresses. Data collection and sample analysis were driven by requirements specified for the development of a United Kingdom sewer flow model termed “MOSQITO”, with the basic chemical parameters ie; COD, BOD and ammonia, of sewage and sewer sediments. A data collection programme is described which assesses the feasibility of using combined sewer sediment preparation protocols, normally used for these chemical analyses, to enumerate bacterial indicator organisms present in deposited sediments. The data were analysed to investigate whether the methods used were precise in terms of repeatability, prior to more extensive studies being undertaken to provide sewer sediment data for bacterial numbers.