Kinetic and microbiological characterization of aerobic granules performing partial nitritation of a low-strength wastewater at 10 °C.
A granular airlift reactor enriched in ammonia oxidizing bacteria (AOB) was operated at 10 °C performing stable partial nitritation in the long-term. The reactor treated a synthetic low-strength influent during 250 days with an average nitrogen loading rate of 0.63 ± 0.06 g N L(-1) d(-1). Nitrate production was barely detected, being the average concentration in the effluent of 0.6 ± 0.3 mg N-NO3 L(-1). Furthermore, a suitable effluent for a subsequent reactor performing the anammox process was achieved. A maximum specific growth rate as high as 0.63 ± 0.05 d(-1) was determined by performing kinetic experiments with the granular sludge in a chemostat and fitting the results to the Monod model. Pyrosequencing analysis showed a high enrichment in AOB (41 and 65% of the population were identified as Nitrosomonas genus on day 98 and 233, respectively) and an effective repression of nitrite oxidizing bacteria in the long-term. Pyrosequencing analysis also identified the coexistence of nitrifying bacteria and heterotrophic psychrotolerant microorganisms in the granular sludge. Some psychrotolerant microorganisms are producers of cryoprotective extracellular polymeric substances that could explain the better survival of the whole consortia at cold temperatures.
GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, Ed. Q-Campus UAB, 08193, Bellaterra, Barcelona, Spain.
Clara
C
Reino
GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, Ed. Q-Campus UAB, 08193, Bellaterra, Barcelona, Spain.
María Eugenia
ME
Suárez-Ojeda
GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, Ed. Q-Campus UAB, 08193, Bellaterra, Barcelona, Spain; Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft, 2628 BC, The Netherlands.
Julio
J
Pérez
GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, Ed. Q-Campus UAB, 08193, Bellaterra, Barcelona, Spain. Electronic address: julian.carrera@uab.cat.
Julián
J
Carrera
D019149:Bioreactors / Q000382:microbiology*; D009573:Nitrites; D009584:Nitrogen; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*
D009573:Nitrites; D009584:Nitrogen; D012722:Sewage; D062065:Wastewater
AOB-Enrichment; Anammox; Low temperature; Mainstream; NOB-Repression; Partial nitritation