The role of extracellular polymeric substances on carbon capture in a high rate activated sludge A-stage system

2017 ◽  
Vol 322 ◽  
pp. 428-434 ◽  
Author(s):  
Maureen N. Kinyua ◽  
Matthew Elliott ◽  
Bernhard Wett ◽  
Sudhir Murthy ◽  
Kartik Chandran ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Carbon Capture ◽  
Extracellular Polymeric Substances ◽  
High Rate ◽  
Stage System

Role of extracellular polymeric substances in the acute inhibition of activated sludge by polystyrene nanoparticles

2018 ◽  
Vol 238 ◽  
pp. 859-865 ◽  
Author(s):  
Li-Juan Feng ◽  
Jing-Jing Wang ◽  
Shu-Chang Liu ◽  
Xiao-Dong Sun ◽  
Xian-Zheng Yuan ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Polystyrene Nanoparticles

Polyhydroxyalkanoates, triacylglycerides and glycogen in a high rate activated sludge A-stage system

2017 ◽  
Vol 316 ◽  
pp. 350-360 ◽  
Author(s):  
Maureen N. Kinyua ◽  
Mark W. Miller ◽  
Bernhard Wett ◽  
Sudhir Murthy ◽  
Kartik Chandran ◽  
...  
Keyword(s):  
Activated Sludge ◽  
High Rate ◽  
Stage System

Role of extracellular polymeric substances in bioflocculation of activated sludge microorganisms under glucose-controlled conditions

2010 ◽  
Vol 44 (15) ◽  
pp. 4505-4516 ◽  
Author(s):  
Appala R. Badireddy ◽  
Shankararaman Chellam ◽  
Paul L. Gassman ◽  
Mark H. Engelhard ◽  
Alan S. Lea ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Controlled Conditions

Modeling of organic substrate transformation in the high-rate activated sludge process

2015 ◽  
Vol 71 (7) ◽  
pp. 971-979 ◽  
Author(s):  
Thomas Nogaj ◽  
Andrew Randall ◽  
Jose Jimenez ◽  
Imre Takacs ◽  
Charles Bott ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Oxygen Demand ◽  
Organic Substrate ◽  
High Rate ◽  
State Variables ◽  
Modified Model ◽  
Soluble Substrate ◽  
Substrate Model ◽  
Dual Substrate

This study describes the development of a modified activated sludge model No.1 framework to describe the organic substrate transformation in the high-rate activated sludge (HRAS) process. New process mechanisms for dual soluble substrate utilization, production of extracellular polymeric substances (EPS), absorption of soluble substrate (storage), and adsorption of colloidal substrate were included in the modified model. Data from two HRAS pilot plants were investigated to calibrate and to validate the proposed model for HRAS systems. A subdivision of readily biodegradable soluble substrate into a slow and fast fraction were included to allow accurate description of effluent soluble chemical oxygen demand (COD) in HRAS versus longer solids retention time (SRT) systems. The modified model incorporates production of EPS and storage polymers as part of the aerobic growth transformation process on the soluble substrate and transformation processes for flocculation of colloidal COD to particulate COD. The adsorbed organics are then converted through hydrolysis to the slowly biodegradable soluble fraction. Two soluble substrate models were evaluated during this study, i.e., the dual substrate and the diauxic models. Both models used two state variables for biodegradable soluble substrate (SBf and SBs) and a single biomass population. The A-stage pilot typically removed 63% of the soluble substrate (SB) at an SRT <0.13 d and 79% at SRT of 0.23 d. In comparison, the dual substrate model predicted 58% removal at the lower SRT and 78% at the higher SRT, with the diauxic model predicting 32% and 70% removals, respectively. Overall, the dual substrate model provided better results than the diauxic model and therefore it was adopted during this study. The dual substrate model successfully described the higher effluent soluble COD observed in the HRAS systems due to the partial removal of SBs, which is almost completely removed in higher SRT systems.

scholarly journals Colloids, flocculation and carbon capture – a comprehensive plant-wide model

2018 ◽  
Vol 79 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Hélène Hauduc ◽  
Ahmed Al-Omari ◽  
Bernhard Wett ◽  
Jose Jimenez ◽  
Haydee De Clippeleir ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Carbon Capture ◽  
Oxygen Demand ◽  
High Rate ◽  
Reactor Performance ◽  
Whole Plant ◽  
Solids Retention ◽  
Methane Potential ◽  
Intracellular Storage ◽  
Activated Sludge Systems

Abstract The implementation of carbon capture technologies such as high-rate activated sludge (HRAS) systems are gaining interests in water resource and recovery facilities (WRRFs) to minimize carbon oxidation and maximize organic carbon recovery and methane potential through biosorption of biodegradable organics into the biomass. Existing activated sludge models were developed to describe chemical oxygen demand (COD) removal in activated sludge systems operating at long solids retention times (SRT) (i.e. 3 days or longer) and fail to simulate the biological reactions at low SRT systems. A new model is developed to describe colloidal material removal and extracellular polymeric substance (EPS) generation, flocculation, and intracellular storage with the objective of extending the range of whole plant models to very short SRT systems. In this study, the model is tested against A-stage (adsorption) pilot reactor performance data and proved to match the COD and colloids removal at low SRT. The model was also tested on longer SRT systems where effluents do not contain much residual colloids, and digestion where colloids from decay processes are present.

scholarly journals Layered Extraction and Adsorption Performance of Extracellular Polymeric Substances from Activated Sludge in the Enhanced Biological Phosphorus Removal Process

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3358 ◽  
Author(s):  
Daxue Li ◽  
Hailing Xi
Keyword(s):  
Activated Sludge ◽  
Functional Groups ◽  
Phosphorus Removal ◽  
Extracellular Polymeric Substances ◽  
Cation Exchange Resin ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Adsorption Performance ◽  
Biological Phosphorus

A large amount of phosphorus was found in the extracellular polymeric substances (EPS) of activated sludge used in enhanced biological phosphorus removal (EBPR), so the role of EPS and extracellular phosphorus in EBPR should not be neglected. The composition and properties of tightly bound EPS (TB-EPS) and loosely bound EPS (LB-EPS) were significantly different, and it was necessary to study the adsorption performance of EPS through the fractionating of activated sludge into LB-EPS, TB-EPS and microbial cells. In this study, the adsorption performance of LB-EPS and TB-EPS for phosphate was explored by extracting LB-EPS and TB-EPS via sonication and cation exchange resin (CER), respectively. The results indicated that the sonication-CER method was an efficient and reliable extraction method for EPS with a synergistic effect. The performance of EPS in the adsorption/complexing of phosphate was excellent because of its abundant functional groups. Specifically, the type and content of metal elements and functional groups in TB-EPS were much greater than those in LB-EPS, which led to the key role of TB-EPS in the adsorption/complexing of phosphate. Finally, a metabolic model for EBPR with consideration of the adsorption performance of LB-EPS and TB-EPS was proposed.

Strong selection pressures impact the capacity of flocculating activated sludge bacteria to granulate

2013 ◽  
Vol 67 (8) ◽  
pp. 1678-1687 ◽  
Author(s):  
G. A. C. Ehlers ◽  
S. J. Turner
Keyword(s):  
Particle Size ◽  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
High Rate ◽  
Volume Index ◽  
Size Analysis ◽  
Liquid Separation ◽  
Granule Formation ◽  
Selection Pressures ◽  
The Impact

The capacity of activated sludge (AS) microbial populations to form dense granules offers the potential to establish efficiently settleable biomass. This has the potential to circumvent problems around ineffective solids–liquid separation and sensitivity to variable chemical oxygen demand (COD) loads. Although a number of studies have evaluated aerobic laboratory granulation reactors as high-rate treatment systems, the biological processes involved in aerobic granulation are not fully understood. Concomitantly, the impact of operation parameters such as organic loading rates is also important for granulation. The ability of a flocculating AS community to granulate under different selection pressures was evaluated in a laboratory sequencing batch reactor by determining levels of extracellular polymeric substances (EPS) and particle size fractions that developed under feast (4.74 g COD L−1) and famine (0.42 g COD L−1) nutrient regimes. The efficiency of solid–liquid separation was also measured. Aggregation indices showed levels >94% and a sludge volume index factor of up to 0.94, which strongly suggested granule formation; however, microscopy evaluation showed a mixture of flocs and granules. Particle size analysis revealed binomial distribution patterns of particles in the reactor which shifted to smaller tightly bound particles (<200 μm) although large particles (>600 μm) were also measured during famine conditions. This coincided with increases in EPS levels although EPS quantities were low and it is postulated that this could have impacted granule formation: the EPS in the bacterial aggregates were consumed since the AS community was starved.

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