TY - JOUR
T1 - Modeling hydraulic transport and anaerobic uptake by PAOs and GAOs during wastewater feeding in EBPR granular sludge reactorste
AU - Weissbrodt, David G.
AU - Holliger, Christof
AU - Morgenroth, Eberhard
PY - 2017/8/1
Y1 - 2017/8/1
N2 - New-generation bioprocesses using granular sludge aim for a high-rate removal of nutrients from wastewater with low footprint. Achieving enhanced biological phosphorus removal (EBPR) relies on the design of sludge beds and wastewater feeding conditions to optimally load the biomass and to select for polyphosphate- (PAOs) over glycogen-accumulating organisms (GAOs) and over other heterotrophs. A hydraulic–metabolic mathematical model was developed to elucidate the impact of hydraulic transport patterns and environmental conditions on the PAO/GAO competition during up-flow feeding through an EBPR granular sludge bed. Tracer experiments highlighted plug-flow regimes with dispersion under both rapid (9 m h−1, Rebed = 1.6, Pez = 7.2, Pet = 4.6) and slow (0.9 m h−1, Rebed = 0.2, Pez = 21.3, Pet = 3.4) feeding. Non-turbulent regimes (Rebed << 103) promote a safe implementation of simultaneous fill/draw. Feeding time, pH, and temperature significantly impacted bacterial competition for carbon uptake under anaerobic slow feeding. Feeding duration should be designed to avoid full depletion of intracellular storage polymers within static granules. PAOs bear twice longer feeding than GAOs by using both polyphosphate and glycogen hydrolysis to sustain anaerobic C-uptake. Alkaline conditions (pH 7.25–8.0) by, e.g., dosing lime in the feed select for PAOs independently of temperature (10−30°C). A twice higher bed is required for full anaerobic conversions at 10 rather than 20°C. Biosystem responses for anaerobic C-uptake can be anticipated using the model toward designing robust anaerobic selectors to manage the microbial resource in EBPR granular sludge. Biotechnol. Bioeng. 2017;114: 1688–1702.
AB - New-generation bioprocesses using granular sludge aim for a high-rate removal of nutrients from wastewater with low footprint. Achieving enhanced biological phosphorus removal (EBPR) relies on the design of sludge beds and wastewater feeding conditions to optimally load the biomass and to select for polyphosphate- (PAOs) over glycogen-accumulating organisms (GAOs) and over other heterotrophs. A hydraulic–metabolic mathematical model was developed to elucidate the impact of hydraulic transport patterns and environmental conditions on the PAO/GAO competition during up-flow feeding through an EBPR granular sludge bed. Tracer experiments highlighted plug-flow regimes with dispersion under both rapid (9 m h−1, Rebed = 1.6, Pez = 7.2, Pet = 4.6) and slow (0.9 m h−1, Rebed = 0.2, Pez = 21.3, Pet = 3.4) feeding. Non-turbulent regimes (Rebed << 103) promote a safe implementation of simultaneous fill/draw. Feeding time, pH, and temperature significantly impacted bacterial competition for carbon uptake under anaerobic slow feeding. Feeding duration should be designed to avoid full depletion of intracellular storage polymers within static granules. PAOs bear twice longer feeding than GAOs by using both polyphosphate and glycogen hydrolysis to sustain anaerobic C-uptake. Alkaline conditions (pH 7.25–8.0) by, e.g., dosing lime in the feed select for PAOs independently of temperature (10−30°C). A twice higher bed is required for full anaerobic conversions at 10 rather than 20°C. Biosystem responses for anaerobic C-uptake can be anticipated using the model toward designing robust anaerobic selectors to manage the microbial resource in EBPR granular sludge. Biotechnol. Bioeng. 2017;114: 1688–1702.
KW - aerobic granular sludge
KW - EBPR
KW - feeding and environmental impacts
KW - hydraulic–metabolic model
KW - PAO/GAO selection
KW - system analysis and mathematical modeling
UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85019904878&origin=resultslist
U2 - 10.1002/bit.26295
DO - 10.1002/bit.26295
M3 - Article
C2 - 28322436
AN - SCOPUS:85019904878
SN - 0006-3592
VL - 114
SP - 1688
EP - 1702
JO - Biotechnology and Bioengineering
JF - Biotechnology and Bioengineering
IS - 8
ER -