MiDAS: Field Guide to the Microbes of
Activated Sludge and Anaerobic Digesters

As a central collaborative workspace, MiDAS (Microbial Database for Activated Sludge) is available to researchers and wastewater treatment practitioners to facilitate a better understanding of the microbial ecology of the engineered ecosystems of activated sludge, anaerobic digesters, and related wastewater treatment systems. The ambition of the field guide is to summarise all the knowledge about the ecology of the important microorganisms present in these systems. Integral to this goal is the ability to link an organism’s name with its putative function. Additionally, we have developed the MiDAS taxonomy (available for download), which is a manual curation of the 16S rRNA gene sequence-based SILVA taxonomy that proposes a name for all genus-level taxa observed to be abundant by large-scale amplicon sequencing of communities of full-scale activated sludge wastewater treatment plants and their associated anaerobic digesters. The taxonomy can be used to classify unknown sequences, and the online MiDAS field guide links the identity to a referenced summary of their in situ metabolism, morphotype, and distribution in these systems. The inclusion of abundance information for influent wastewater, activated sludge, and anaerobic digesters allows an assessment of immigration on population structure. The goal is to provide a common taxonomy for the field that will provide a solid foundation for the study of microbial ecology of the activated sludge process and related treatment processes.



Start browsing your microbes now!



07 September 2016
Top abundant bacteria present in anaerobic digesters and influent wastewater are now included in MiDAS database.

25 August 2016
We are including microorganisms found in anaerobic digesters and influent wastewater in our database

07 September 2015
Find out more about official release and download new version of MiDAS taxonomy

The online MiDAS field guide is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.


The MiDAS taxonomy is a manual curation of the Silva database and is redistributed for non-commercial use only.


Citing MiDAS: McIlroy S.J., Saunders A.M., Albertsen M., Nierychlo M., McIlroy B., Hansen A.A., Karst S.M., Nielsen J.L., Nielsen P.H. (2015) MiDAS: the field guide to the microbes of activated sludge. Database, Vol. 2015

Contact us at mail@midasfieldguide.org