Skip to main content


Title: Quantification of the relationship between effluent quality and biological quality : final report
Author: A. Gunby
Author: I. Milne
Author: M. Wheeler
Document Type: Monograph
This report is the final output from the Environment Agency, Anglian Region Operational Investigation 597: Quantification of the relationship between effluent quality and biological quality. The Agency has a national system for biological assessment of water quality but no formal method of relating discharge quality to biologically assessed water quality. This project arose from an identified need for such a methodology, which would enhance the Agencys ability to target investment and demonstrate improvements. The objectives of the project were, firstly to use existing data to identify relationships between the chemical quality of sewage treatment works (STW) effluent and the biological quality of receiving waters, and, secondly, to use these relationships to develop a predictive protocol for assessing the likely effects on biological quality of effluent improvements. Data on a wide range of appropriate variables was provided and a series of data manipulations and multivariate statistical analyses were canied out to try and identify relationships of interest. Unfortunately it was not possible to identify any useful relationships, primarily because the majority of the STWs for which all the necessary variables were available were not actually having a large impact on the receiving waters (at least according to the data used) and also because of the high degree of variability in the data, particularly the biological data. The failure to find useful relationships, meant that it would not be possible to develop the envisaged protocol and the project was therefore terminated. This report documents the data analysis exercise undertaken. From the outset of this project it was recognised that an experimental approach, with targeted sampling, might be required but that existing data should first be assessed to avoid unnecessary effort. The outcome of the project indicates that if the development of a method to relate discharge quality to biological is to be pursued, a specifically targeted sampling approach will probably be required.
Publisher: Environment Agency
Publication Date: 1997
Publication Place: Peterborough
Subject Keywords: EffluentsSewage treatmentWater qualityWater quality measurementsBiological analysisData
Geographic Keywords: EA Anglian
Extent: 35
Total file downloads: 296

Download PDF    Display PDF in separate tab