Denitrification is commonly employed in biological nitrogen removal processes to enhance water quality. However, substantial knowledge gaps remain concerning the overall community structure, population dynamics, and metabolism of different organic carbon sources.
This systematic review by researchers in the US provides a summary of current findings relating to the microbial ecology of denitrification in biological wastewater treatment processes.
DNA fingerprinting-based analysis has revealed a high level of microbial diversity in denitrification reactors, and highlighted the impacts of carbon sources in determining the overall denitrifying community composition.
Stable isotope probing, fluorescence in situ hybridisation, microarrays and meta-omics further link community structure with function, by identifying the functional populations and their gene regulatory patterns at the transcriptional and translational levels.
This review article stresses the need to integrate microbial ecology information into conventional denitrification design and operation at full scale. Some emerging questions, from physiological mechanisms to practical solutions – for example, eliminating nitrous oxide emissions, and supplementing more sustainable carbon sources than methanol – are also discussed.
A combination of high-throughput approaches is next in line for thorough assessment of wastewater denitrifying community structure and function. Although denitrification is used as an example here, this synergy between microbial ecology and process engineering is applicable to other biological wastewater treatment processes.