Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems
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Mdpi
Materia
Nitrogen removal Activated sludge Ammonium oxidizing bacteria Nitrogen oxidizing bacteria Low temperature
Date
2020-08-31Referencia bibliográfica
Kruglova, A., Kesulahti, J., Minh Le, K., Gonzalez-Martinez, A., Mikola, A., & Vahala, R. (2020). Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems. Water, 12(9), 2450. [doi:10.3390/w12092450]
Sponsorship
Finnish Water Utilities Association (VVY)Abstract
In this study, the microbial community of nitrifying activated sludge adapted to Finnish
climate conditions was studied to clarify the microbial populations involved in low-temperature
nitrification. Microbial community analysis of five full-scale wastewater treatment plants (WWTPs)
showed several di erences compared to WWTPs from other countries with a similar climate.
In particular, very low abundance of ammonium oxidizing bacteria (AOBs) (altogether < 0.25% of
total community) as well as typical NOBs (<0.35%) and a high abundance of orders Cytophagales and
Micrococcales was observed in all Finnish WWTPs. To shed light on the importance of autotrophic
and heterotrophic nitrifying processes, laboratory studies of activated sludge were carried out with a
presence of and a lack of organic carbon in wastewater at 10 1 C. Two di erent sludge retention
times (SRTs) were compared to determine the e ect of this operational parameter on low-temperature
nitrogen removal. The important role of previously reported Candidatus Nitrotogaarctica for nitrite
oxidizing in cold climate conditions was confirmed in both full-scale and laboratory scale results.
Additionally, potential participation of Dokdonella sp. and Flexibacter sp. in nitrogen removal at
low-temperatures is proposed. Operation at SRT of 100 days demonstrated more stable and e cient
nitrogen removal after a sharp temperature decrease compared to 14 days SRT.