Organic degradation and extracellular products of pure oxygen aerated activated sludge under different F/M conditions

2019 ◽  
Vol 279 ◽  
pp. 189-194 ◽  
Author(s):  
Hong-Ling Zhang ◽  
Wei-Li Jiang ◽  
Rong Liu ◽  
Ying Zhou ◽  
Yong Zhang
Author(s):  
Jia-Ying He ◽  
Hong-Ling Zhang ◽  
Hong Wang ◽  
Ya-Qi Hu ◽  
Yong Zhang

Abstract The effects of pure oxygen aeration on compositional characteristics of soluble microbial products (SMP) and extracellular polymeric substances (EPS) of the activated sludge acclimated in a sequential batch reactor (SBR) were explored in batch mode. The structure of the extracellular products would change with different aeration methods or aeration rates. The proportion of SMP of most oxygen aerated sludge was less than 10%, while that in air aerated sludge was as high as 30%–40%. The proportion of TB-EPS decreased from 56.95% to 30.63%, and the proportion of LB-EPS increased obviously with the increase of oxygen aeration rate. The contents of the protein (PN) and the polysaccharide (PS) of extracellular products with oxygen aeration were significantly different, and the PN was much higher than PS (p < 0.05). The zeta potential of each component in activated sludge was negative, gradually decreasing with the progress of biological treatment. The fluorescence peaks in SMP, LB-EPS and TB-EPS with pure oxygen aeration were attributed to tryptophan PN-like and humic acid-like fractions. The results showed that the proportion of the components in the extracellular products could be regulated by adjusting the aeration rate and aeration mode, so as to optimize the treatment process of activated sludge.


2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Veronica R. Brand ◽  
Laurel D. Crosby ◽  
Craig S. Criddle

ABSTRACTMultiple clades within a microbial taxon often coexist within natural and engineered environments. Because closely related clades have similar metabolic potential, it is unclear how diversity is sustained and what factors drive niche differentiation. In this study, we retrieved three near-complete Competibacter lineage genomes from activated sludge metagenomes at a full-scale pure oxygen activated sludge wastewater treatment plant. The three genomes represent unique taxa within theCompetibacteraceae. A comparison of the genomes revealed differences in capacity for exopolysaccharide (EPS) biosynthesis, glucose fermentation to lactate, and motility. Using quantitative PCR (qPCR), we monitored these clades over a 2-year period. The clade possessing genes for motility and lacking genes for EPS biosynthesis (CPB_P15) was dominant during periods of suspended solids in the effluent. Further analysis of operational parameters indicate that the dominance of the CPB_P15 clade is associated with low-return activated sludge recycle rates and low wasting rates, conditions that maintain relatively high levels of biomass within the system.IMPORTANCEMembers of the Competibacter lineage are relevant in biotechnology as glycogen-accumulating organisms (GAOs). Here, we document the presence of threeCompetibacteraceaeclades in a full-scale activated sludge wastewater treatment plant and their linkage to specific operational conditions. We find evidence for niche differentiation among the three clades with temporal variability in clade dominance that correlates with operational changes at the treatment plant. Specifically, we observe episodic dominance of a likely motile clade during periods of elevated effluent turbidity, as well as episodic dominance of closely related nonmotile clades that likely enhance floc formation during periods of low effluent turbidity.


2015 ◽  
Vol 87 (6) ◽  
pp. 498-505
Author(s):  
Somshekhar Kundral ◽  
Ratnaji Mudragada ◽  
Ernesto Coro ◽  
Manny Moncholi ◽  
Nelson Mora ◽  
...  

1987 ◽  
Vol 19 (3-4) ◽  
pp. 529-538 ◽  
Author(s):  
Gary L. Amy ◽  
Curtis W. Bryant ◽  
Mosen Belyani

Differences in the nature of soluble organic matter were measured for various full-scale wastewater treatment processes. Conventional activated sludge, pure oxygen activated sludge, biofiltration, granular activated carbon, and tertiary sand filtration were evaluated. Effluent soluble organic matter was analyzed by ultrafiltration for the apparent molecular weight distribution of soluble organic carbon and UV-absorbing material. The effects of annual season, secondary treatment process, and tertiary treatment process upon the properties of the effluent soluble organic matter were statistically significant at the 99% level. Effluent properties from the various treatments were sufficiently different to support the concept of the selection of appropriate treatments to minimize the effluent concentration of specific fractions of the soluble organic material as required for specific water reuse applications.


1986 ◽  
Vol 18 (7-8) ◽  
pp. 307-311 ◽  
Author(s):  
A. Donáth-Jobbágy ◽  
J. Káimán ◽  
R. Hajós

The efficiency of two possible intensification methods of activated sludge waste water treatment (pure oxygen activation and activated carbon addition) were compared. Experiments were carried out in laboratory scale equipment with variable reactor volume (maximum capacity 20,0 dm3, settling tank vol. 15 dm3). In order to detect even minor differences, we operated completely identical units in parallel runs, with one representing a traditional system as reference. A model sewage of industrial character, diluted milk, was used as influent and in the course of activated carbon intensification experiments an anion-active detergent was added as a poorly biodegradable model material to be removed mainly by adsorption. Reactor loads were gradually increased - from low values to overloading - by decreasing the dilution of milk or by reducing reactor volume. The effects of different intensification methods on the effluent pollution level (COD value and anion-active detergent content) and on the settling properties of sludge were examined as a function of loading. The efficiency of both intensification methods was found to be increasing with increasing loading. Comparison of the two systems showed activated carbon intensification to be more efficient in the removal of soluble COD and extremely useful in the elimination of a poorly biodegradable material.


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