Long-term stability of partial nitritation-anammox for treatment of municipal wastewater in a moving bed biofilm reactor pilot system
Journal article, 2020

Nitrogen removal fromthe mainstream of municipalwastewaterwith partial nitritation-anammox (PNA) would be highly beneficial with regard to the uses of energy and organic carbon. However, the challenges of process instability, low nitrogen removal rates (NRR) and unwanted aerobic nitrite oxidation need to be solved to reach large-scale implementation. Here, we have operated pilot-scale moving bed biofilm reactors (MBBRs) for mainstream treatment, together with sidestream treatment of sludge liquor from anaerobic digestors, for over 900 days to investigate process stability, reactor performance and microbial community structure at realistic conditions. The MBBR biofilm contained stable and high relative abundances of anammox bacteria (10–32%) consisting of twomajor Brocadia sp. populations, and several populations of aerobic ammonia-oxidising bacteria (AOB) within Nitrosomonas sp. (0.2–3.1%), as assessed by 16S rDNA amplicon sequencing. In addition, nitrite-oxidising bacteria (NOB) consisting of Nitrospira sp. (0.4–0.8%) and Nitrotoga sp. (up to 0.4%)were present.Nitrogen was removed at a peak rate of 0.66 g Nm−2 d−1 (0.13 kg Nm−3 d−1)with a nitrate production over ammonium consumption of 15% by the NOB, at operation with continuous aeration at 15 °C. However, during most periods with continuous aeration, the NRRwas lower (≈0.45 g Nm−2 d−1),with larger relative nitrate production (≈40%), presumably due to problems to maintain stable residual ammonium concentrations during wetweather mainstream flows. Changing reactor operation to intermittent aeration decreased the NRR but did not help in suppressing the NOB. The study shows that with MBBRs, stablemainstreamPNA can be attained at realistic NRR, but with need for post-treatment of nitrate, since effective NOB suppression was hard to achieve.

Partial nitritation-anammox Mainstream Municipal wastewater treatment MBBR Microbial community analysis


David Gustavsson

VA Syd

Sweden Water Research

Carolina Suarez

Chalmers, Architecture and Civil Engineering, Water Environment Technology

University of Gothenburg

Britt-Marie Wilen

Chalmers, Architecture and Civil Engineering, Water Environment Technology

Malte Hermansson

University of Gothenburg

Frank Persson

Chalmers, Architecture and Civil Engineering, Water Environment Technology

Science of the Total Environment

00489697 (ISSN) 18791026 (eISSN)

Vol. 714 136342

Nitrogen removal from wastewater with anammox for low resource usage and small carbon footprint

Formas (2014-1528), 2015-01-01 -- 2017-12-31.

Driving Forces

Sustainable development

Subject Categories

Water Engineering


Water Treatment


Basic sciences



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