TY - GEN
T1 - Biofilm morphology, structure, and detachment in denitrifying fluidized bed bioreactors (DFBBRs)
AU - Eldyasti, Ahmed
AU - Nakhla, George
AU - Zhu, Jesse
N1 - Publisher Copyright:
Copyright © 2013 Water Environment Federation. All Rights Reserved.
PY - 2013
Y1 - 2013
N2 - Divalent cations, such as magnesium (Mg2+) and calcium (Ca2+), have been shown to change the biofilm structure and detachment rate. The impact of calcium concentrations on the biofilm morphology, structure, detachment and denitrification efficiency in Denitrifying Fluidized Bed Bioreactors (DFBBRs) was investigated. The DFBBRs were operated on a synthetic municipal wastewater at five different calcium concentrations ranging from the typical Ca2+ concentration of the tap water (20 mg Ca2+/L) to 240 mg Ca2+/L at two different C/N ratios of 5 and 3.5 in phases I and II, respectively for a period of 200 days. The results showed that calcium concentrations played a significant role in biofilm morphology with the detachment rates for R120Ca (bioreactor with a Ca2+ concentration of 120 mg/L), R180Ca, and R240Ca 90% and 70% lower than for R20Ca and R60Ca, respectively. The optimum influent calcium concentration at both organic and nitrogen loading rates was 120 mg Ca2+/L, with higher concentrations exhibiting fractured and weak biofilms. Specific denitrification rates did not change with changing the C/N ratio at elevated Ca2+ concentration bioreactors while with lower Ca2+ concentrations, the specific denitrification rates dropped by 20%-40%. Nutrients and Ca2+ mass balances were closed with reasonable accuracy. Some of the data presented here is published in Eldyasti et al.
AB - Divalent cations, such as magnesium (Mg2+) and calcium (Ca2+), have been shown to change the biofilm structure and detachment rate. The impact of calcium concentrations on the biofilm morphology, structure, detachment and denitrification efficiency in Denitrifying Fluidized Bed Bioreactors (DFBBRs) was investigated. The DFBBRs were operated on a synthetic municipal wastewater at five different calcium concentrations ranging from the typical Ca2+ concentration of the tap water (20 mg Ca2+/L) to 240 mg Ca2+/L at two different C/N ratios of 5 and 3.5 in phases I and II, respectively for a period of 200 days. The results showed that calcium concentrations played a significant role in biofilm morphology with the detachment rates for R120Ca (bioreactor with a Ca2+ concentration of 120 mg/L), R180Ca, and R240Ca 90% and 70% lower than for R20Ca and R60Ca, respectively. The optimum influent calcium concentration at both organic and nitrogen loading rates was 120 mg Ca2+/L, with higher concentrations exhibiting fractured and weak biofilms. Specific denitrification rates did not change with changing the C/N ratio at elevated Ca2+ concentration bioreactors while with lower Ca2+ concentrations, the specific denitrification rates dropped by 20%-40%. Nutrients and Ca2+ mass balances were closed with reasonable accuracy. Some of the data presented here is published in Eldyasti et al.
KW - Biofilm Morphology
KW - Calcium
KW - Denitrification
KW - Extracellular Polymeric Substances (EPS)
KW - Fluidized Bed
UR - http://www.scopus.com/inward/record.url?scp=84938400131&partnerID=8YFLogxK
U2 - 10.2175/193864713813716516
DO - 10.2175/193864713813716516
M3 - Conference contribution
AN - SCOPUS:84938400131
T3 - 86th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2013
SP - 6543
EP - 6552
BT - 86th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2013
PB - Water Environment Federation
T2 - 86th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2013
Y2 - 5 October 2013 through 9 October 2013
ER -