Meta-analysis of biogenic odour management solutions for operational drinking water treatment plants
Jin Zhu, Richard M. Stuetz, Lisa Hamilton, Kaye Powe, Bojan Tamburic
Abstract
Unpleasant odours in drinking water are a challenge for the water industry as consumers often perceive them as contamination and register complaints. Biogenic odour management at operational drinking water treatment plants requires knowledge of the treatability of odorants and odour-producing microbes, and it needs to ensure that other water quality parameters are not compromised. This study investigated the management options for odour at drinking water treatment plants using the PSALSAR meta-analysis framework. Most drinking water treatment plants use conventional treatment trains to manage odour. More advanced treatment technologies, such as membrane filtration and biological reactors, are mainly operated at pilot-scale and only achieved strong odour removal when they were used as a polishing step or in combination with pretreatment. To date, 35 specific odorants have been detected in operational treatment plants. We evaluated odour removal of the common musty/earthy odorant methylisoborneol (MIB; mean inlet concentration 1 to 136 ng/L) by different treatment processes. MIB concentrations after conventional treatment were occasionally reported to be above the odour detection threshold (10 ng/L), but they could be reduced below this threshold by activated carbon adsorption or ozonation. Biological activated carbon coupled with ozonation was reported to effectively remove MIB (86.4 %–100 % removal), even when inlet concentrations were as high as 58–164 ng/L. Concerningly, MIB concentrations often increased after sedimentation or sand filtration without pretreatment, probably due to the release of intracellular MIB. We propose a number of strategies including more targeted raw water quality monitoring, improved jar tests, and the identification and use of operational control points, to inform proactive in-plant odour management. • PSALSAR meta-analysis framework was used to evaluate odour treatment processes. • 109 operational examples with 24 distinct treatment trains were analysed. • 33 odorants beyond geosmin and MIB have been reported at operational scale. • Conventional treatment removes microbial cells but struggles with dissolved odorants. • Activated carbon adsorbs dissolved odorants effectively, especially post-ozonation.