Skip to main content


Title: Biological assessment of inorganic and organic enrichment of watercourses by Hatfield, Rye Meads, Deephams and Bishop Stortford sewage effluents
Author: Les Ruse
Document Type: Monograph
The four sewage discharges investigated have previously been considered too difficult to assess biologically because of the depth and width of the watercourse being considered for sensitive area status under the Urban Waste Water Treatment Directive. This study assessed each discharge for both inorganic nutrient and organic enrichment using collections of midge pupal skins to indirectly assess benthic algal growth. There was a doubling in the proportion of algal grazing midges downstream of Rye Meads sewage discharge compared with upstream. There was also a proportional increase in grazers downstream of Deephams sewage effluent despite there being a very high proportion of grazers upstream. This effluent also demonstrated the most marked increase in organic enrichment of the four considered. There was no evidence that either Hatfield or Bishops Stortford sewage discharges were supplying inorganic nutrients limiting to algal growth upstream of these impacts.
Publisher: Environment Agency
Publication Place: Fobney Mead
Subject Keywords: Sewage treatmentEffluentsUrban Waste Water Treatment DirectivePollution monitoringChemical monitoring
Geographic Keywords: Hatfield (Hertfordshire)Bishop's Stortford
Extent: n.p. [12]
Total file downloads: 274

Download PDF    Display PDF in separate tab