Role of sludge volume index in anaerobic sludge granulation in a hybrid anaerobic reactor

2016 ◽  
Vol 283 ◽  
pp. 338-350 ◽  
Author(s):  
Pragya Gupta ◽  
T.R. Sreekrishnan ◽  
Shaikh Z. Ahammad
Keyword(s):  
Volume Index ◽  
Anaerobic Sludge ◽  
Sludge Volume Index ◽  
Anaerobic Reactor ◽  
Sludge Granulation

Granulation of anaerobic sludge in the sulfate-reducing up-flow sludge bed (SRUSB) of SANI® process

2013 ◽  
Vol 68 (3) ◽  
pp. 560-566 ◽  
Author(s):  
T. Hao ◽  
H. Lu ◽  
H. K. Chui ◽  
Mark C. M. van Loosdrecht ◽  
G. H. Chen
Keyword(s):  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Biomass Concentration ◽  
Volume Index ◽  
Anaerobic Sludge ◽  
Sludge Volume Index ◽  
Sulfate Reducing ◽  
Full Development ◽  
Sludge Granulation

This study reports on anaerobic sludge granulation in a laboratory-scale sulfate-reducing up-flow sludge bed (SRUSB) in a novel sulfate reduction, autotrophic denitrification and nitrification integrated (SANI®) process for treatment of saline sewage. Granulation occurred in 30 d and reached full development in 90 d. The sulfate-reducing granules grew up to around 1 mm after 90 d with 21 mL/g SVI5 (sludge volume index measured after 5 min) and the biomass concentration reached 29 g/L after 4 months' operation. The reactor removed 89% chemical oxygen demand (COD) and reduced 75% sulfate within 1 h of hydraulic retention time, under a COD loading rate of up to 6.4 kg COD/(m3 · d).

Cultivation of polyhydroxybutyrate-rich aerobic granular sludge in a sequencing batch reactor

2006 ◽  
Vol 6 (6) ◽  
pp. 81-87 ◽  
Author(s):  
J. Wang ◽  
H.Q. Yu
Keyword(s):  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Volume Index ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Second Step ◽  
Sludge Volume Index ◽  
Flat Shape ◽  
Sludge Granulation

In this study a two-step strategy was adopted to cultivate Polyhydroxybutyrate (PHB)-rich aerobic granular sludge in a sequencing batch reactor (SBR) fed with a synthetic wastewater. In the first step both oxygen and ammonia were initially limited, in order to enhance the PHB-storage ability of sludge. In the second step granular sludge was cultivated to get a high PHB volumetric productivity. The PHB content of sludge increased to 43.1±2.0% in the first step. During the sludge granulation, the PHB content was constant at 40±4.6%. With the granulation, the settling ability of the PHB-rich sludge continuously improved, as evidenced by a decreased sludge volume index. The matured PHB-rich granular sludge presented a buff color and regular morphology with elliptical and flat shape.

On-line measurements of settling characteristics in activated sludge

1997 ◽  
Vol 36 (4) ◽  
pp. 307-312
Author(s):  
Michael R. Rasmussen ◽  
Torben Larsen
Keyword(s):  
Activated Sludge ◽  
Settling Velocity ◽  
Continuous Measurement ◽  
Batch Reactor ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Dynamic Variations ◽  
On Line ◽  
Settling Column ◽  
Settling Characteristics

An on-line settling column for measuring the dynamic variations of settling velocity of activated sludge has been developed. The settling column is automatic and self-cleansing insuring continuous and reliable measurements. The settling column was tested on sludge from a batch reactor where sucrose was added as an impulse to activated sludge. The continuous measurement of settling velocity revealed a highly dynamic response after the sucrose was added. The results were verified with simultaneous measurement of the initial settling rate. A 200 hour experiment showed variations in settling velocity, which was not apparent in the DSVI (Diluted Sludge Volume Index).

scholarly journals β1-blocker in sepsis

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Daisuke Hasegawa ◽  
Ryota Sato ◽  
Osamu Nishida
Keyword(s):  
Heart Rate ◽  
Oxygen Delivery ◽  
Sinus Tachycardia ◽  
Meta Analysis ◽  
Lactate Production ◽  
Volume Index ◽  
Initial Resuscitation ◽  
Randomized Controlled ◽  
Metabolic Systems

Abstract Background The use of ultrashort-acting β1-blockers recently has attracted attention in septic patients with non-compensatory tachycardia. We summarized the metabolic and hemodynamic effects and the clinical evidence of ultrashort-acting β1-blockers. Main body A recent meta-analysis showed that ultrashort-acting β1-blockers reduced the mortality in septic patients with persistent tachycardia. However, its mechanism to improve mortality is not fully understood yet. We often use lactate as a marker of oxygen delivery, but an impaired oxygen use rather than reduced oxygen delivery has been recently proposed as a more reasonable explanation of hyperlactatemia in patients with sepsis, leading to a question of whether β1-blockers affect metabolic systems. While the stimulation of the β2-receptor accelerates glycolysis and lactate production, the role of β1-blocker in lactate production remains unclear and studies investigating the role of β1-blockers in lactate kinetics are warranted. A meta-analysis also reported that ultrashort-acting β1-blockers increased stroke volume index, while it reduced heart rate, resulting in unchanged cardiac index, mean arterial pressure, and norepinephrine requirement at 24 h, leading to an improvement of cardiovascular efficiency. On the other hand, a recent study reported that heart rate reduction using fast esmolol titration in the very early phase of septic shock caused hemodynamic instability, suggesting that ultrashort-acting β1-blockers should be started only after completing initial resuscitation. While many clinicians still do not feel comfortable controlling sinus tachycardia, one randomized controlled trial in which the majority had sinus tachycardia suggested the mortality benefit of ultrashort-acting β1-blockers. Therefore, it still deems to be reasonable to control sinus tachycardia with ultrashort-acting β1-blockers after completing initial resuscitation. Conclusion Accumulating evidence is supporting the use of ultrashort-acting β1-blockers while larger randomized controlled trials to clarify the effect of ultrashort-acting β1-blockers are still warranted.

Effects of sludge settling characteristics in the BNR system

2000 ◽  
Vol 42 (3-4) ◽  
pp. 283-288 ◽  
Author(s):  
Z. Yun ◽  
W. Yo ◽  
Y. Yi ◽  
S. Choi ◽  
E. Choi ◽  
...  
Keyword(s):  
Settling Tank ◽  
Volume Index ◽  
Anoxic Zone ◽  
Sludge Volume Index ◽  
Analytical Accuracy ◽  
Fast Settling ◽  
Sludge Settling ◽  
Extracellular Polymer ◽  
Sludge Settleability ◽  
Settling Characteristics

Although the BNR system design assumes no sludge settling problems in the final settling tank, the fluctuation of daily loading and up to 40% of anaerobiosis in the BNR system would be considerable factors in determining the sludge settleability. The sludge volume index (SVI) is a classical parameter to examine the sludge settleability but it has a limited value to evaluate the overall settling characteristics. The extracellular polymer (ECP) content in sludge has long been considered as an indicator of biological flocculation in activated sludge process, but the skepticism on analytical accuracy limits the usage in settling study. This study focused on evaluating the BNR system performance related to the sludge settling characteristics under the controlled laboratory environment. A 5-stage BNR system (anaerobic-anoxic-3 stage oxic) was operated with the HRTs from 3.9 to 7.6 hours. In order to determine the sludge settling properties, both SVI and ECP content were monitored. The ECP contents in the sludge sample were measured by the slime-washing step followed by high-G centrifugation and sonication. The gel-electrophoresis was used to detect the DNA in the sonicated samples to determine the intracellular polymer contamination. It has been found that the anaerobiosis in the anaerobic and anoxic zone that consisted of 37% of reactor volume could not deteriorate the sludge settling properties even at the HRT of 3.9 hours. The SVI values of sludge taken from the reactor with the HRT of 7.2 hours averaged to less than 50 mL/gr. It was postulated that a fast settling sludge in the BNR system could not always ensure production of clear effluent. The sludge with very low SVI might not achieve a complete biological flocculation potential. In addition, the degree of denitrification in the BNR system could be related to the sludge settleability.

Aeration tank odour by dimethyl sulphoxide (DMSO) waste in sewage

2007 ◽  
Vol 55 (5) ◽  
pp. 319-326 ◽  
Author(s):  
D. Glindemann ◽  
J.T. Novak ◽  
J. Witherspoon
Keyword(s):  
Bulk Water ◽  
Sulphate Reduction ◽  
Anaerobic Sludge ◽  
Aeration Tank ◽  
Dimethyl Sulphide ◽  
Reduction Mechanism ◽  
Anaerobic Conditions ◽  
Sludge Flocs ◽  
Oxidation Resistant

Sewage plants can experience dimethyl sulphide (DMS) odour problems by at least one mg/L dimethylsulphoxide (DMSO) waste residue in plant influent, through a DMSO/DMS reduction mechanism. This bench-scale batch study simulates in bottles the role of poor aeration in wastewater treatment on the DMSO/DMS and sulphate/H2S reduction. The study compares headspace concentrations of sulphide odorants developed by activated sludge (closed bottles, half full) after six hours under anoxic versus anaerobic conditions, with 0 versus 2 mg/L DMSO addition. Anoxic sludge (0.1–2 mg/L dissolved oxygen, DO) with DMSO resulted in about 50 ppmv DMS and no other sulphide, while DMSO-free sludge was free of detectable sulphides. Anaerobic sludge (no measurable DO to the point of sulphate reduction) with DMSO resulted in 22/4/37 ppmv of H2S/methanethiol (MT)/DMS, while DMSO-free sludge resulted in 44/8/2 ppmv of H2S/MT/DMS. It is concluded that common “anoxic” aeration tank zones with measurable DO in bulk water but immeasurable DO inside sludge flocs (nitrate reducing) experience DMSO reduction to DMS that is oxidation resistant and becomes the most important odorant. Under anaerobic conditions, H2S from sulphate reduction becomes an additional important odorant. A strategy is developed that allows operators to determine from the quantity of different sulphides whether the DMSO/DMS mechanism is important at their wastewater plant.

Organic loading rate (OLR) regulation for enhancement of aerobic sludge granulation: Role of key microorganism and their function

2019 ◽  
Vol 653 ◽  
pp. 630-637 ◽  
Author(s):  
Zhiming Zhang ◽  
Jianxiang Qiu ◽  
Ronghao Xiang ◽  
Haitian Yu ◽  
Xiangyang Xu ◽  
...  
Keyword(s):  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Sludge Granulation ◽  
Aerobic Sludge

The biobed® EGSB (expanded granular sludge bed) system covers shortcomings of the upflow anaerobic sludge blanket reactor in the chemical industry

1997 ◽  
Vol 35 (10) ◽  
pp. 183-188 ◽  
Author(s):  
George R. Zoutberg ◽  
Peter de Been
Keyword(s):  
Waste Water ◽  
Chemical Industry ◽  
Granular Sludge ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Special Configuration ◽  
Anaerobic Reactor ◽  
High Concentrations ◽  
Anaerobic Sludge Blanket ◽  
Brewery Yeast

In this paper a new type of anaerobic reactor is presented. The system has been developed by Biothane Systems and is marketed under the name Biobed® EGSB reactor (Expanded Granular Sludge Bed). In this reactor it is possible to grow and maintain a granular sludge under high liquid (10 m/h) and gas velocities (7 m/h). The most striking feature is the growth of biomass in a granular form, similar to the UASB granules: no carrier material is used. The process is specially suitable to treat waste water that contains compounds that are toxic in high concentrations and that only can be degraded in low concentrations (chemical industry). An example is given for a waste water originating from a chemical factory (Caldic Europoort) in the Netherlands. In this factory formaldehyde is produced from methanol. The waste water is characterised by high concentrations of these compounds (formaldehyde to 10 g/l and methanol to 20 g/l). Due to the special configuration of the anaerobic reactor it is possible to realise a removal efficiency for both compounds of more than 98%. It is also possible to operate the reactor as an ultra high loaded anaerobic reactor (to 30 kg COD/m3.day) for applications in other sectors of industry (e.g. brewery, yeast, sugar, corn ethanol production etc).

scholarly journals Characteristics of the Coagulate Obtained During the Process of Model Wastewater Treatment

2015 ◽  
Vol 1 ◽  
pp. 9
Author(s):  
Julija Brovkina ◽  
Galija Shulga ◽  
Jurijs Ozolins ◽  
Zilgma Irbe ◽  
Maris Turks ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Volume Index ◽  
Optimal Time ◽  
Sludge Volume Index ◽  
Organic Part ◽  
Main Drawback ◽  
Average Size ◽  
By Products ◽  
Polyaluminium Chloride

In the process of wastewater treatment by coagulation a large amount of sediment is being produced, which is the main drawback of this method. Therefore, the development of utilization or recirculation technology of the waste obtained, the research of the obtained by-products should be conducted. Within the scope of this work, the sediment, that is being formed during the coagulation of the model wastewater containing the wood originated pollutants, was studied. Using the aluminium-containing composition coagulant on a base of polyaluminium chloride, coagulates characterized by the low sludge volume index within 30 minutes (89 ml g-1), and the optimal time of sedimentation is 20-30 minutes. The coagulate particles have an average size of 45.8 μm. The derived coagulate is composed primarily of carbon (27.9%), oxygen (49.4%) and aluminum (10.9%). Carbon, oxygen and hydrogen belong to an organic part of coagulate-the wood pollutants, which, in turn, has a high content of hemicellulose. It is concluded that the existing hemicellulose in the obtained coagulate is characterized by O-acetyl-4-O-methyl-D-glucuron-β-D-xylan with β-(1-4)-glucomannose.

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