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Start-up of autotrophic nitrogen removal reactors via sequential biocatalyst addition

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Abstract
A procedure for start-up of oxygen-limited autotrophic nitrification-denitrification (OLAND) in a lab-scale rotating biological contactor (RBC) is presented. In this one-step process, NH4+ is directly converted to N-2 without the need for an organic carbon source. The approach is based on a sequential addition of two types of easily available biocatalyst to the reactor during start-up: aerobic nitrifying and anaerobic, granular methanogenic sludge. The first is added as a source of aerobic ammonia-oxidizing bacteria (AAOB), the second as a possible source of planctomycetes including anaerobic ammonia-oxidizing bacteria (AnAOB). The initial nitrifying biofilm serves as a matrix for anaerobic cell incorporation. By subsequently imposing oxygen limitation, one can create an optimal environment for autotrophic N removal. In this way, N removal of about 250 mg of N L-1 d(-1) was achieved after 100 d treating a synthetic NH4+-rich wastewater. By gradually imposing higher loads on the reactor, the N elimination could be increased to about 1.8 g of N L-1 d(-1) at 250 d. The resulting microbial community was compared with that of the inocula using general bacterial and AAOB- and planctomycete-specific PCR primers. Subsequently, the RBC reactor was shown to treat a sludge digestor effluent under suboptimal and strongly varying conditions. The RBC biocatalyst was also submitted to complete absence of oxygen in a fixed-film bioreactor (FFBR) and proved able to remove NH4+ with NO2- as electron acceptor (maximal 434 mg of NH4+-N (g of VSS)(-1) d(-1) on day 136). DGGE and real-time PCR analysis demonstrated that the RBC biofilm was dominated by members of the genus Nitrosomonas and close relatives of Kuenenia stuttgartiensis, a known AnAOB. The latter was enriched during FFBR operation, but AAOB were still present and the ratio planctomycetes/AAOB rRNA gene copies was about 4.3 after 136 d of reactor operation. Whether this relates to an active role of AAOB in the anoxic N removal process remains to be solved.
Keywords
ROTATING BIOLOGICAL CONTACTOR, ANAEROBIC AMMONIUM OXIDATION, RICH WASTE-WATER, IN-SITU DETECTION, NITROSOMONAS-EUROPAEA, NITRIFYING BIOFILM, NITRITE, OXYGEN, DENITRIFICATION, NITRIFICATION

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Chicago
Pynaert, Kris, Barth F Smets, Daan Beheydt, and Willy Verstraete. 2004. “Start-up of Autotrophic Nitrogen Removal Reactors via Sequential Biocatalyst Addition.” Environmental Science & Technology 38 (4): 1228–1235.
APA
Pynaert, K., Smets, B. F., Beheydt, D., & Verstraete, W. (2004). Start-up of autotrophic nitrogen removal reactors via sequential biocatalyst addition. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 38(4), 1228–1235.
Vancouver
1.
Pynaert K, Smets BF, Beheydt D, Verstraete W. Start-up of autotrophic nitrogen removal reactors via sequential biocatalyst addition. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 2004;38(4):1228–35.
MLA
Pynaert, Kris, Barth F Smets, Daan Beheydt, et al. “Start-up of Autotrophic Nitrogen Removal Reactors via Sequential Biocatalyst Addition.” ENVIRONMENTAL SCIENCE & TECHNOLOGY 38.4 (2004): 1228–1235. Print.
@article{209175,
  abstract     = {A procedure for start-up of oxygen-limited autotrophic nitrification-denitrification (OLAND) in a lab-scale rotating biological contactor (RBC) is presented. In this one-step process, NH4+ is directly converted to N-2 without the need for an organic carbon source. The approach is based on a sequential addition of two types of easily available biocatalyst to the reactor during start-up: aerobic nitrifying and anaerobic, granular methanogenic sludge. The first is added as a source of aerobic ammonia-oxidizing bacteria (AAOB), the second as a possible source of planctomycetes including anaerobic ammonia-oxidizing bacteria (AnAOB). The initial nitrifying biofilm serves as a matrix for anaerobic cell incorporation. By subsequently imposing oxygen limitation, one can create an optimal environment for autotrophic N removal. In this way, N removal of about 250 mg of N L-1 d(-1) was achieved after 100 d treating a synthetic NH4+-rich wastewater. By gradually imposing higher loads on the reactor, the N elimination could be increased to about 1.8 g of N L-1 d(-1) at 250 d. The resulting microbial community was compared with that of the inocula using general bacterial and AAOB- and planctomycete-specific PCR primers. Subsequently, the RBC reactor was shown to treat a sludge digestor effluent under suboptimal and strongly varying conditions. The RBC biocatalyst was also submitted to complete absence of oxygen in a fixed-film bioreactor (FFBR) and proved able to remove NH4+ with NO2- as electron acceptor (maximal 434 mg of NH4+-N (g of VSS)(-1) d(-1) on day 136). DGGE and real-time PCR analysis demonstrated that the RBC biofilm was dominated by members of the genus Nitrosomonas and close relatives of Kuenenia stuttgartiensis, a known AnAOB. The latter was enriched during FFBR operation, but AAOB were still present and the ratio planctomycetes/AAOB rRNA gene copies was about 4.3 after 136 d of reactor operation. Whether this relates to an active role of AAOB in the anoxic N removal process remains to be solved.},
  author       = {Pynaert, Kris and Smets, Barth F and Beheydt, Daan and Verstraete, Willy},
  issn         = {0013-936X},
  journal      = {ENVIRONMENTAL SCIENCE \& TECHNOLOGY},
  keyword      = {ROTATING BIOLOGICAL CONTACTOR,ANAEROBIC AMMONIUM OXIDATION,RICH WASTE-WATER,IN-SITU DETECTION,NITROSOMONAS-EUROPAEA,NITRIFYING BIOFILM,NITRITE,OXYGEN,DENITRIFICATION,NITRIFICATION},
  language     = {eng},
  number       = {4},
  pages        = {1228--1235},
  title        = {Start-up of autotrophic nitrogen removal reactors via sequential biocatalyst addition},
  url          = {http://dx.doi.org/10.1021/es030081+},
  volume       = {38},
  year         = {2004},
}

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