TY - JOUR
T1 - Selection of ammonium oxidizing bacteria (AOB) over nitrite oxidizing bacteria (NOB) based on conversion rates
AU - Wu, Jun
AU - He, Chengda
AU - van Loosdrecht, Mark C M
AU - Pérez, Julio
PY - 2016/11/15
Y1 - 2016/11/15
N2 - The enrichment of r-strategist ammonium oxidizing bacteria (r-AOB) to enhance nitritation and effective nitrogen removal was studied. A lab-scale three-compartment reactor system removing nitrogen from synthetic wastewater containing ammonium and COD (NH4 +:COD ratio at ca. 1:8) was used. A stable nitritation-denitritation process was achieved. The first compartment was anoxic for denitrification and the last two compartments were aerobic to oxidize ammonium into nitrite (nitritation). Recirculation between last and first compartment allowed for effective denitrification. Nitritation was achieved by enhancing the growth of fast growing r-AOB and setting a high NH4 + concentrations in the first of the two aerobic compartments (named as r-AOB selector). The sludge was wasted adaptively to maintain NH4 + concentration between 10 and 20 mg N/L in the r-AOB selector. The adaptive sludge wastage resulted in a short sludge retention time (SRT) of 4.2 days that led to full nitritation within 100 days of operation. Kinetic parameter estimation indicated that the maximum specific growth rate for AOB increased from 0.39 to 1.45 d−1, while the NH4 + half saturation constant increased from 0.51 to 5.23 mg N/L, indicating the transition from K-AOB (slower growing K-strategist AOB) to r-AOB. Mathematical simulation indicated that the SRT and NH4 + concentration were the main factors determining the outcome of nitrifying species competition.
AB - The enrichment of r-strategist ammonium oxidizing bacteria (r-AOB) to enhance nitritation and effective nitrogen removal was studied. A lab-scale three-compartment reactor system removing nitrogen from synthetic wastewater containing ammonium and COD (NH4 +:COD ratio at ca. 1:8) was used. A stable nitritation-denitritation process was achieved. The first compartment was anoxic for denitrification and the last two compartments were aerobic to oxidize ammonium into nitrite (nitritation). Recirculation between last and first compartment allowed for effective denitrification. Nitritation was achieved by enhancing the growth of fast growing r-AOB and setting a high NH4 + concentrations in the first of the two aerobic compartments (named as r-AOB selector). The sludge was wasted adaptively to maintain NH4 + concentration between 10 and 20 mg N/L in the r-AOB selector. The adaptive sludge wastage resulted in a short sludge retention time (SRT) of 4.2 days that led to full nitritation within 100 days of operation. Kinetic parameter estimation indicated that the maximum specific growth rate for AOB increased from 0.39 to 1.45 d−1, while the NH4 + half saturation constant increased from 0.51 to 5.23 mg N/L, indicating the transition from K-AOB (slower growing K-strategist AOB) to r-AOB. Mathematical simulation indicated that the SRT and NH4 + concentration were the main factors determining the outcome of nitrifying species competition.
KW - K-strategist AOB
KW - NOB repression
KW - Partial nitrification
KW - r-strategist AOB
UR - http://www.scopus.com/inward/record.url?scp=84978523883&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2016.07.019
DO - 10.1016/j.cej.2016.07.019
M3 - Article
AN - SCOPUS:84978523883
SN - 1385-8947
VL - 304
SP - 953
EP - 961
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -