Obtaining evidence for 'Evidence based management': The taste and odour problem

摘要

This article explains how scientific evidence generated through Welsh Water and academic collaboration is driving forward our ability to safeguard drinking water quality and improve customer acceptability. This is investigated in the face of increasing risk from climate change, specifically focusing on the issue of taste and odour in drinking water supply. Earthy and musty taste and odour complaints have been attributed primarily to the production of volatile organic compounds, methylisoborneol (MIB) and geosmin, in water supply reservoirs by filamentous cyanobacteria. One of the key triggers of production has been identified as the relative abundance of ammonium compared to other nitrogen sources, principally nitrate. When other nutrients, e.g. phosphorus, are available to specific strains of cyanobacteria, and environmental conditions of temperature and light are favourable, rapid growth stimulates production of MIB and geosmin. These compounds are stored internally by the cyanobacteria cells, but can be released into the water column later, causing elevated concentrations that may not be removed at the water treatment works. In order to prevent this issue exacerbating due to climate change, catchment management interventions, well evidenced by sound scientific research, are urgently needed.