Achieving nitritation and anammox enrichment in a single moving-bed biofilm reactor treating reject water.
A biofilm with high nitrifying efficiency was converted into a nitritating and thereafter a nitritating-anammox biofilm in a moving-bed biofilm reactor at 26.5 (+/- 0.5) degrees C by means of a combination of intermittent aeration, low dissolved oxygen concentration, low hydraulic retention time, free ammonia and furthermore, also by elevated HCO3- concentration. Nitrite-oxidizing bacteria (NOB) were more effectively suppressed by an enhanced HCO3- concentration range of 1200-2350 mg/L as opposed to free-ammonia-based process control where NOBs recovered from inhibition; the respective total-nitrogen removal rates were 0.3 kg N/(m3 x d) and 0.2 kg N/(m3 x d). The biofilm modification strategies resulted in a shift in bacterial community as the NOB Nitrobacter spp. were replaced with NOB belonging to the genus Nitrospira spp. and were closely related to Candidatus Nitrospira defluvii. A community of anaerobic ammonium-oxidizing microorganisms -uncultured Planctomycetales bacterium clone P4 (closely related to Candidatus Brocadia fulgida)--was developed.
Institute of Chemistry, University of Tartu, 14a Ravila St, Tartu, Estonia. Ivar.Zekker@ut.ee
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Zekker
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Rikmann
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Tenno
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Saluste
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Tomingas
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Menert
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Loorits
Vallo
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Lemmiksoo
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Tenno
D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007220:Industrial Waste / Q000517:prevention & control*; D009573:Nitrites / Q000378:metabolism*; D009576:Nitrobacter / Q000378:metabolism*; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
D007220:Industrial Waste; D009573:Nitrites; D000644:Quaternary Ammonium Compounds