Biodegradation

, Volume 25, Issue 6, pp 923–934

Structural integrity affects nitrogen removal activity of granules in semi-continuous reactors

  • Cesar R. Mota
  • Melanie A. Head
  • Jon C. Williams
  • Lucy Eland
  • Jay J. Cheng
  • Francis L. de los ReyesIII
Original Paper

DOI: 10.1007/s10532-014-9712-3

Cite this article as:
Mota, C.R., Head, M.A., Williams, J.C. et al. Biodegradation (2014) 25: 923. doi:10.1007/s10532-014-9712-3

Abstract

Granules were observed after more than two years of operation in two semi-continuously fed intermittently aerated reactors treating swine wastewater with aerobic:anoxic cycles of 1:1 h and 1:4 h. Subsequently, the granules and flocs were compared with respect to physical characteristics, activity, and microbial community structure. Granules exhibited higher specific nitrification and denitrification rates than flocs. However, once granule structural integrity was disrupted, the rates decreased to levels similar to those of flocs. Membrane hybridizations using 16S rRNA-targeted probes showed that ammonia oxidizing bacteria populations in flocs and granules were dominated by Nitrosomonas and Nitrosococcus mobilis. Granules provided better conditions for Nitrospira compared to flocs. The diversities of the dominant bacterial populations in granules and flocs were not significantly different. Our findings highlight the importance of structural integrity of granules to their nitrogen removing activity.

Keywords

Fluorescence in situ hybridization Aerobic granules Structure Flocs Nitrification Denitrification Particle size 

List of symbols and abbreviations

Xf

VSS concentration in the IA reactor attributed to floccular biomass, mg VSS/L

Xg

VSS concentration in the IA reactor attributed to granules, mg VSS/L

Xr

VSS concentration in the IA reactor, mg VSS/L

VSS

Volatile suspended solids

IA

Intermittent aeration

TSS

Total suspended solids

No

Initial concentration of N in the reactor, mg N/L

dN/dtg

Change in N concentration over time due to granule activity, mg N/L*d

dN/dtf

Change in N concentration over time due to floccular biomass activity, mg/L*d

VSS

Volatile suspended solids, mg/L

NH3–N

Ammonia nitrogen, mg N/L

NO3–N

Nitrate nitrogen, mg N/L

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Cesar R. Mota
    • 1
    • 4
  • Melanie A. Head
    • 2
  • Jon C. Williams
    • 1
  • Lucy Eland
    • 3
  • Jay J. Cheng
    • 2
  • Francis L. de los ReyesIII
    • 1
  1. 1.Department of Civil, Construction, and Environmental EngineeringNorth Carolina State UniversityRaleighUSA
  2. 2.Department of Biological and Agricultural EngineeringNorth Carolina State UniversityRaleighUSA
  3. 3.School of Civil Engineering and GeosciencesNewcastle UniversityNewcastleUK
  4. 4.Departamento de Engenharia Sanitária e AmbientalUniversidade Federal de Minas GeraisBelo HorizonteBrazil

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