Long-term performance of enhanced biological phosphorus removal with increasing concentrations of silver nanoparticles and ions

RSC Advances ◽  
2013 ◽  
Vol 3 (25) ◽  
pp. 9835 ◽  
Author(s):  
Hong Chen ◽  
Xiong Zheng ◽  
Yinguang Chen ◽  
Hui Mu
Keyword(s):  
Silver Nanoparticles ◽  
Phosphorus Removal ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Long Term Performance ◽  
Term Performance ◽  
Biological Phosphorus

Uncertainty and variability in enhanced biological phosphorus removal (EBPR) stoichiometry: consequences for process modelling and optimization

2010 ◽  
Vol 61 (7) ◽  
pp. 1793-1800 ◽  
Author(s):  
Dwight Houweling ◽  
Yves Comeau ◽  
Imre Takács ◽  
Peter Dold
Keyword(s):  
Phosphorus Removal ◽  
Volatile Fatty Acids ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Feed Composition ◽  
P Limitation ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus ◽  
P Removal

The overall potential for enhanced biological phosphorus removal (EBPR) in the activated sludge process is constrained by the availability of volatile fatty acids (VFAs). The efficiency with which polyphosphate accumulating organisms (PAOs) use these VFAs for P-removal, however, is determined by the stoichiometric ratios governing their anaerobic and aerobic metabolism. While changes in anaerobic stoichiometry due to environmental conditions do affect EBPR performance to a certain degree, model-based analyses indicate that variability in aerobic stoichiometry has the greatest impact. Long-term deterioration in EBPR performance in an experimental SBR system undergoing P-limitation can be predicted as the consequence of competition between PAOs and GAOs. However, the observed rapid decrease in P-release after the change in feed composition is not consistent with a gradual shift in population.

Microbial storage products, biomass density, and settling properties of enhanced biological phosphorus removal activated sludge

2001 ◽  
Vol 43 (1) ◽  
pp. 173-180 ◽  
Author(s):  
A. J. Schuler ◽  
D. Jenkins ◽  
P. Ronen
Keyword(s):  
Phosphorus Removal ◽  
P Uptake ◽  
Volume Index ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Biomass Density ◽  
Model Predictions ◽  
Storage Products ◽  
Biological Phosphorus

The relationships between bacterial storage products, density, and settling characteristics were determined in a laboratory-scale sequencing batch reactor (SBR) enhanced biological phosphorus removal (EBPR) system. Both long-term and single anaerobic-aerobic cycle variations in these properties were studied. Increased polyphosphate (PP) content of the biomass during long-term operation resulted in improved sludge volume index (SVI) values. End-aerobic phase (after phosphate (P) uptake) values were consistently lower than end-anaerobic phase (after P release) values. Neither filamentous nor slime bulking were evident by microscopic observations. Biomass density increased at a rate of 1.2 mg/L per each 1% increase in biomass P content. End-aerobic phase samples had an average 25% higher buoyant density than end-anaerobic phase samples, which was attributed to aerobic P uptake. Biomass density was negatively correlated with SVI values, and SVI values increased sharply at low biomass density. A mathematical model developed by Mas et al. (1985) was modified to predict total cell density based on literature values of PP, glycogen (GLY), and poly-b-hydroxybutyrate (PHB) densities. Model predictions were in good agreement with experimental results, although improved measurement of PP density is required to improve model predictions.

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