News & Events
Challenging Central Dogmas in Microbial Ecology of Wastewater Treatment Systems
Speaker(s): Prof. Per Halkjær Nielsen, Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Denmark
When: 05 July 2017 (3:00 - 4:00pm)
Where: SBS CR2 (Level 1)
Type: Seminars


Wastewater treatment is becoming part of the circular sustainability movement by integrating energy production and resource recovery into the production of clean water. Microorganisms are key players in this process, so understanding their identity, physiology, and ecology is an essential part of making wastewater treatment as efficient and productive as possible. So far, few comprehensive studies of advanced wastewater handling systems have taken place, and most of the process-critical organisms are still not identified or poorly understood. We have conducted a comprehensive, 10-year study of 30 wastewater treatment plants, 40 anaerobic digesters, and influent and effluent wastewater to produce a more holistic view of the entire microbiome. The analysis involved amplicon sequencing, metagenomics, single-cell microbiology including Raman microspectroscopy, and process data to describe and understand the ecophysiology of key microorganisms and their influence on plant operation. We discovered that many of the commonly regarded dogmas in wastewater microbiology can be questioned – e.g. related to the effect of immigration, selective pressure on certain microbial groups, which bacteria are important in biological P-removal, and the microbiological quality of the effluent. Novel approaches to study the wastewater microbiome will also be demonstrated.


Per Halkjær Nielsen is full professor at the Department of Chemistry and Bioscience at Aalborg University, Denmark where he heads the multidisciplinary Center for Microbial Communities ( He is also a visiting professor at SCELSE since 2012. His research group has been active in environmental biotechnology for over 25 years. He has been among the pioneers in the introduction and implementation of the new DNA sequencing technologies in the water engineering field, and has developed MiDAS, an open online microbiology resource for wastewater treatment and bioenergy production. He chaired the International Water Association (IWA) specialist group “Microbial Ecology and Water Engineering” for 8 years (2005-2013) and is chair of the IWA-ISME BioCluster. He has received many awards for his work, the latest is a personal “Villum Investigator Award” of US$4.5 million.