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Letteratura scientifica selezionata sul tema "Floc properties"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 3 febbraio 2022

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Articoli di riviste sul tema "Floc properties"

Mehta, Ashish J., William H. McAnally, Farzin Samsami e Andrew J. Manning. "REVISITING THE ROLE OF AGGREGATION IN THE SETTLING OF COHESIVE FLOCS IN THE MARINE ENVIRONMENT". Coastal Engineering Proceedings, n. 36 (30 dicembre 2018): 17. http://dx.doi.org/10.9753/icce.v36.sediment.17.

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The settling velocity is the single-most important property governing the transport of cohesive flocs in the marine environment. In that regard, the instantaneously changing diameter, density and shear strength of flocs are the defining properties which distinguish floc transport from that of cohesionless particles. Thus, consideration of aggregation, which includes the dynamics of floc growth and breakup due to floc-floc collisions as well as flow-induced shearing of flocs, is a critical component of floc transport modeling.

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Ding, Yanmei, Jianhai Zhao, Lei Wei, Wenpu Li e Yongzhi Chi. "Effects of Mixing Conditions on Floc Properties in Magnesium Hydroxide Continuous Coagulation Process". Applied Sciences 9, n. 5 (7 marzo 2019): 973. http://dx.doi.org/10.3390/app9050973.

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Magnesium hydroxide continuous coagulation process was used for treating simulated reactive orange wastewater in this study. Effects of mixing conditions and retention time on the coagulation performance and floc properties of magnesium hydroxide were based on the floc size distribution (FSD), zeta potential, and floc morphology analysis. Floc formation and growth in different reactors were also discussed. The results showed that increasing rapid mixing speed led to a decrease in the final floc size. The floc formation process was mainly carried out in a rapid mixer; a rapid mixing speed of 300 rpm was chosen according to zeta potential and removal efficiency. Reducing retention time caused a relatively small floc size in all reactors. When influent flow was 30 L/h (retention time of 2 min in rapid mixer), the average floc size reached 8.06 μm in a rapid mixer; through breakage and re-growth, the floc size remained stable in the flocculation basin. After growth, the final floc size reached 11.21 μm in a sedimentation tank. The removal efficiency of reactive orange is 89% in the magnesium hydroxide coagulation process.

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Nielsen, P. H., T. R. Thomsen e J. L. Nielsen. "Bacterial composition of activated sludge - importance for floc and sludge properties". Water Science and Technology 49, n. 10 (1 maggio 2004): 51–58. http://dx.doi.org/10.2166/wst.2004.0606.

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Activated sludge flocs consist of numerous constituents which, together with other factors, are responsible for floc structure and floc properties. These properties largely determine the sludge properties such as flocculation, settling and dewaterability. In this paper we briefly review the present knowledge about the role of bacteria in relation to floc and sludge properties, and we present a new approach to investigate the identity and function of the bacteria in the activated sludge flocs. The approach includes identification of the important bacteria and a characterization of their physiological and functional properties. It is carried out by use of culture-independent molecular biological methods linked with other methods to study the physiology and function, maintaining a single cell resolution. Using this approach it was found that floc-forming properties differed among the various bacterial groups, e.g. that different microcolony-forming bacteria had very different sensitivities to shear and that some of them deflocculated under anaerobic conditions. In our opinion, the approach to combine identity with functional analysis of the dominant bacteria in activated sludge by in situ methods is a very promising way to investigate correlations between presence of specific bacteria, and floc and sludge properties that are of interest.

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Yukselen, M. A., e J. Gregory. "Properties of flocs formed using different coagulants". Water Supply 2, n. 5-6 (1 dicembre 2002): 95–101. http://dx.doi.org/10.2166/ws.2002.0156.

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The effects of shear on the formation and break-up of flocs generated using aluminium sulphate (“alum”), polyaluminium chloride and a cationic polyelectrolyte have been investigated using conventional jar test procedure and by continuous optical monitoring. Using the experimentally determined optimum dosage, the breakage of flocs was followed at a high stirring speed, corresponding to average shear rate (G) of about 330-520 s-1. Most of the breakage occurred within a few seconds of increasing the shear rate. After each breakage the stirring rate was reduced to the original value to allow the flocs to re-grow. For alum and polyaluminium chloride, it was found that only limited re-growth of flocs occurred indicating a significant irreversibility of the floc break-up process. Residual turbidity increased after floc breakage and re-growth, indicating a reduction in sedimentation rate of the re-grown flocs, consistent with the continuous monitoring results. For the cationic polyelectrolyte, the re-growth of flocs occurred to a much greater extent and floc breakage was almost fully reversible.

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Ehlers, G. A. C., D. Wagachchi e S. J. Turner. "Nutrient conditions and reactor configuration influence floc size distribution and settling properties". Water Science and Technology 65, n. 1 (1 gennaio 2012): 156–63. http://dx.doi.org/10.2166/wst.2011.849.

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Floc formation and settleability is critical for effective solid–liquid separation in many wastewater treatment processes. This study aimed to investigate the relationship between particle size distribution and nutrient conditions in different bioreactor configurations. Size distribution profiles of flocs that formed in continuous (B1), continuous with clarifier and return sludge (B2) and SBR (B3) reactors were investigated in parallel under identical nutrient conditions. An eight-fold dilution of the influent COD of a synthetic dairy processing wastewater resulted in a ‘feast and famine’ regime that triggered significant effects on the biomass and flocculation characteristics. Floc size analysis of reactor MLSS revealed a shift in floc sizes when reactors were fed with the minimum (famine) COD wastewater feed (0.61 g L−1). Increasing floc size distributions were detected for all reactors during the minimum COD feed although different size patterns were observed for different reactor configurations. These increases corresponded with variations in aggregation and EPS quantities. The SBR yielded comparatively larger flocs when operated under both COD feeds as indicated by d(0.9) values (90% of particles ≤ d in size). Overall the results indicated that floc formation and floc size are mediated by nutrient concentrations and represents an important step towards improved solid–liquid separation.

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Zhao, Jianhai, Anmin Wang, Lei Wei, Wenqi Ge, Yongzhi Chi e Yanping Lai. "Effect of kaolin on floc properties for reactive orange removal in continuous coagulation process". Water Science and Technology 78, n. 3 (24 luglio 2018): 571–77. http://dx.doi.org/10.2166/wst.2018.327.

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Abstract Magnesium hydroxide was used as a coagulant for treating reactive orange wastewater in a real continuous process. Effects of kaolin on coagulation performance and floc properties were investigated with controlled experiments through floc size distribution, zeta potential, scanning electron microscopy and Fourier transform infrared spectroscopy. Kaolin had significant influence on magnesium hydroxide-reactive orange floc formation and growth. The results showed that average floc size reached 16.31, 12.88 and 20.50 μm, respectively, in the rapid mixer, flocculation basin and sedimentation tank when kaolin concentration was 10 mg/L and reactive orange initial concentration was 0.25 g/L. The floc size tended to increase with the increase of kaolin suspension to 10 mg/L. All of the flocs under investigation showed that floc breakage led to decreased average floc size and remained stable in the flocculation basin. Reactive orange and kaolin could be removed effectively in the continuous coagulation process. Reactive orange was adsorbed in the surface of magnesium hydroxide through charge neutralization and adsorption.

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Chen, Bo, Daisuke Tatsumi e Takayoshi Matsumoto. "Floc Structure and Flow Properties of Pulp Fiber Suspensions." Nihon Reoroji Gakkaishi 30, n. 1 (2002): 19–25. http://dx.doi.org/10.1678/rheology.30.19.

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Moon, B. H., G. T. Seo, T. S. Lee, S. S. Kim e C. H. Yoon. "Effects of salt concentration on floc characteristics and pollutants removal efficiencies in treatment of seafood wastewater by SBR". Water Science and Technology 47, n. 1 (1 gennaio 2003): 65–70. http://dx.doi.org/10.2166/wst.2003.0017.

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Most seafood wastewater has been treated by the activated sludge process. Due to changes in salt concentration, pollutant loadings and raw materials, the process is not operated satisfactorily to meet effluent regulation. Most problems faced at present are solid liquid separation. In this study, effects of salt concentration on floc characteristics and pollutants removal efficiencies were investigated in treatment of seafood wastewater by SBR. For analyzing fractal dimension of flocs, the small angle laser light scattering (SALLS) method was applied using a Diffraction Particle Sizer (Malvern Instruments). Organic removal efficiencies (in terms of CODMn) decreased with increasing salt concentration, but eventually reached a steady state. Fractal dimension and floc size also showed similar trends with changing salt concentration. The main reasons to reduced pollutant removal efficiencies were deteriorated biological activity and settling properties. The biological activity was affected faster than the floc characteristics by increasing salt concentration. The deteriorated settling properties were explained by decreased size and fractal dimension of floc due to increasing salt concentration. The settling properties of floc such as sludge volume index (SVI) and zone settling velocity (ZSV) were related to size and fractal dimension of floc. The fractal dimension of floc was better related to the settling properties than the size of floc.

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Eriksson, Leif, Inga Steen e Marta Tendaj. "Evaluation of Sludge Properties at an Activated Sludge Plant". Water Science and Technology 25, n. 6 (1 marzo 1992): 251–65. http://dx.doi.org/10.2166/wst.1992.0127.

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Composition of pre-settled water, sludge properties in two different lines of an activated sludge plant, and suspended solids (SS) content in outgoing water were followed three times a week during one year. Sludge characteristics were: settling properties, residual turbidity, floc strength, filtration resistance, amount of extracellular polymers, microscope appearance and total length of filamentous organisms. The outgoing SS could be related to residual turbidity and sludge volume. These factors depended on the floc structure and the filament length. These were determined by sludge load or sludge age, water composition and the hydrodynamic history of the sludge. On basis of these and earlier findings a general model for properties of flocs built by floc-forming organisms in activated sludge is proposed.

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Gregory, J., e V. Dupont. "Properties of flocs produced by water treatment coagulants". Water Science and Technology 44, n. 10 (1 novembre 2001): 231–36. http://dx.doi.org/10.2166/wst.2001.0628.

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Hydrolyzing coagulants are extensively used in water and wastewater treatment, often under conditions where hydroxide precipitation is important, giving “sweep flocculation”. Pre-hydrolyzed coagulants, such as polyaluminium chloride (PACl) are also widely used and have several advantages over traditional additives, such as aluminium sulfate. Their action is usually discussed in terms of cationic species and charge neutralization. However, precipitation may also be important and this aspect has not been considered in detail. The present work has compared the action of alum and three commercial PACl products on model clay suspensions. The conventional jar test procedure has been used, along with measurements of settled floc volume and dynamic monitoring of floc formation and break-up by an optical technique. The latter method gives very useful information on the nature of the flocs produced and their response to different shear conditions. It is clear from the results that the PACl products form larger and stronger flocs than alum. With all coagulants floc breakage appears to be essentially irreversible. Sediment volumes are slightly lower for flocs produced by PACl than by alum, but the value is proportional to the dosage in all cases.

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Più fonti

Tesi sul tema "Floc properties"

Kim, Jinho. "Floc properties in stirred suspensions". Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268458.

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Selomulya, Cordelia Chemical Engineering &amp Industrial Chemistry UNSW. "The Effect of Shear on Flocculation and Floc Size/Structure". Awarded by:University of New South Wales. Chemical Engineering and Industrial Chemistry, 2002. http://handle.unsw.edu.au/1959.4/18226.

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The effect of shear on the evolution of floc properties was investigated to analyse the flocculation mechanisms. Little fundamental attention has been given to the shear influence that often creates compact aggregates, while the floc characteristics might differ in other aggregating conditions. It is thus crucial to understand how flocs evolve to steady state, if their properties are to be 'tailored' to suit subsequent solids-liquid separation processes. In this work, flocculation of monodisperse latex particles of various sizes (60, 380, and 810 nm diameter) via electrolyte addition was carried out in a couette-flow and also in shear fields generated by an axial-flow impeller (Fluid foil A310) and a radial-flow impeller (Rushton R100) in standard mixing tanks. A small-angle light scattering technique was used to acquire information regarding the time variation of floc properties in a non-intrusive manner. The structure was quantified by a measure of fractal dimension, signifying the degree of floc compactness. Estimates of the average floc mass were also obtained from the aggregate scattering patterns. By monitoring the changes in floc structure and mass, corresponding to the size evolution; mechanisms of floc formation, fragmentation, and restructuring were identified. Aggregates of 60 and 380 nm particles were observed to grew larger initially, before decreasing to their equilibrium sizes at moderate shear rates (32 - 100 s-1) in a homogeneous shear environment. Floc restructuring at large length scales occurred extensively, and was responsible for the drop in size, particularly at the early stage of the process. Aggregates of 810 nm particles did not, however, display this behaviour. Flocs of larger primary particles were presumably susceptible to breakage rather than deformation, as they were weaker under comparable conditions. Denser aggregates were found when restructuring transpired, while comparatively tenuous flocs were observed when formation and breakage kinetics were the governing mechanisms. The disparity in floc behaviour at higher shear rates (246 s-1 - 330 s-1) was less apparent. The intense hydrodynamic stresses in those instances inevitably caused fragmentation, regardless of the intrinsic particle properties; hence the observed floc compaction was the product of break-up and re-aggregation. A population balance model, incorporating variation in floc structure, displayed comparable trends in size evolution; verifying that restructuring indeed took an important role under certain flocculation conditions. Similar phenomena were likewise observed with the flocculation in stirred tanks. The results reinforced findings in literature; that while circulation time controlled the process kinetics; the floc size was determined by the turbulent stresses. In addition, the maximum shear levels also influenced the floc structures, with denser aggregates produced in a shear field generated using the radial-flow impeller at equivalent energy dissipation per-unit mass. A correlation between non-dimensional floc factor that embodied the aggregate size and structure, and aggregation factor comprising the significant parameters from flocculation conditions, was proposed. The proposed relationship takes into account aspects such as the aggregate structure, interparticle forces, and particle concentration that are often overlooked in existing relationships, which usually only relate the maximum floc size to the applied energy dissipation rate. It thus provides an improved manner of presenting general flocculation data, as well as a means to predict floc properties produced under a specific aggregation condition. Future studies with increasingly complex systems that resemble real conditions are recommended in order to establish a practical understanding of the flocculation mechanisms, for the purpose of optimising the aggregate properties.

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Balls, Margaret. "Relationships between floc properties and NOM removal using a moorland water source". Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1417138/.

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Natural organic matter, or NOM presents a treatment challenge to the conventional water treatment process and has been associated with the formation of disinfection by-products (DBP’s) such as Tri-halomethanes (THM’s) if not removed prior to the disinfection stage. Poor removal of NOM is also thought to lead to filter performance problems such as turbidity or particle count breakthrough, which represents an increased risk of passage of Cryptosporidium into the treated water. Understanding the complex nature of NOM floc and how its physico-chemical properties relate to the coagulation matrix within the water treatment process is therefore key to optimising NOM removal. This forms the basis of the study which was carried out entirely using a natural raw moorland source water, which is preferable over synthetic kaolin based systems. The experimental programme encompassed both bench-scale and pilot-scale tests, and investigated the effect of changes to a number of variables such as coagulant type, coagulation pH and Fe:DOC ratio on floc physico-chemical properties. The approach taken in this work, of monitoring NOM removal alongside floc properties obtained from the optical flocculation monitor revealed some key trends. Firstly under equivalent shear conditions the coagulant dose almost always correlated with the steady-state maximum floc size, and influenced the flocculation rate. Generally the ferric based systems with the largest and fastest forming floc correlated with the best NOM removal, but when the applied Fe:DOC range was narrow and within an optimal range it was difficult to pin-point the best dose. The organic coagulants polyDADMAC and Zetag 64 formed larger, amd more reversible floc than the ferric based systems but with poor NOM removal. Secondly under equivalent shear conditions the larger flocs exhibited the least resistance to breakage, regardless of the coagulant system. Finally with regard to floc physico-chemical properties and filter performance, some key trends were revealed. Zeta potential influenced both NOM removal and the filtered water quality with considerable improvement noted as the charge tended towards 0 mV, and poor performance in the form of breakthrough as the charge decreased to <-10 mV or >4 mV. Flocculant dosing prior to filtration increased floc reformation and prevented breakthrough when charge destabilisation was sub-optimal, and could prove a useful strategy to employ when experiencing challenging winter conditions.

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Lee, Boon Chong. "The influence of nutrients on floc physicochemical properties and structure in activated sludge processes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28822.pdf.

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Kolda, Bridget C. "Impact of polymer type, dosage, and mixing regime and sludge type on sludge floc properties". Thesis, Virginia Tech, 1995. http://hdl.handle.net/10919/40662.

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This research investigated the impact of sludge type, polymer type (percent mole charge), dosage, mixing rate, and solution ionic strength on bound water content of sludge flocs. Data determined to evaluate the extent of dewatering included: percent dry solids, bulk density, bound water content (determined by dilatometric method), floc density (determined by isopycnic centrifugation), and cake solids concentrations. Calculated floc densities and bound water contents were compared with measured values. The polymer mole charge had marginal impact on bound water content. The optimal polymer dose as determined by dose curves did not necessarily result in the least bound water content. The mixing rate did not have an impact on bound water content of the chemical sludge, but did have an impact on bound water content of the biological sludge. However, the percentage of total water removed that was due to bound water removal was not affected by rate of mixing, polymer mole charge, or polymer dose. Altering solution ionic strength did not appear to improve bound water removal.

The calculated bound water content values determined using measured floc densities were consistently greater than the measured bound water content values determined by dilatometric method. The bound water content per the dilatometric method did not account for all the water present in the floes as determined by the isopycnic centrifugation method.

Master of Science

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Cheung, Mee Chu. "Comparative study of the structural, chemical and physical properties of activated sludge floc from different full-scale wastewater treatment systems". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0013/MQ33959.pdf.

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Fall, Kelsey. "Influence Of Suspended Particle Size And Composition On Particle Image Processing, Estuarine Floc Fractal Properties, And Resulting Estuarine Light Attenuation". W&M ScholarWorks, 2020. https://scholarworks.wm.edu/etd/1593091656.

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Understanding the nature of suspended particles is crucial to explaining water clarity issues in many estuaries, including the Chesapeake Bay and its tidal tributaries. Typical near surface estuarine particles are not individual sediment grains, but rather are clusters of inorganic and organic components known as flocs. Because of their fragile nature, flocs are challenging to observe in-situ, so their influence on the optical properties of the system are not well-known. This dissertation used a combination of state-of-the-art optical instrumentation, including laser scattering and transmissometry, a high-definition particle imaging camera system (PICS), and irradiance meters, along with supporting laboratory analysis techniques to investigate the surface waters of the York River estuary. This work characterized estuarine floc properties while simultaneously identifying relationships between estuarine light attenuation, absorption, and scattering due to flocs as well as other water column constituents. The relative organic fraction of suspended solids was found to be an important control on the fractal nature of estuarine flocs, including primary particle size and density, as well as bulk floc properties. A new approach is presented here that simultaneously solves for multiple floc fractal characteristics (e.g., fractal dimension, primary particle size, and primary particle density) and identifies whether simple fractal models are appropriate to describe individual suspensions. Results indicate that suspensions in the York River estuary with lower organic fraction and higher total suspended solids (TSS) are dominated by larger flocs composed of smaller, denser primary particles. In contrast, suspensions with higher organic fraction and lower TSS are composed of smaller flocs with larger, less dense primary particles. Paradoxically, the organic-rich flocs containing larger, lower density primary particles are, in terms of solids content, actually denser overall. This is because the larger, organic-rich primary particles take up more space within the flocs, leaving less room for water. Diffuse light attenuation, scattering, and absorption were related to the nature of the flocs in the York estuary, as well as to other water column constituents. It was found that as TSS increases, larger, lower density flocs containing less organic matter and more water increasingly dominate. This causes scattering to increase more quickly than TSS. In contrast, absorption increased more slowly than TSS. This is because the organics more prevalent at low TSS absorb more light per mass than the inorganic solids that dominate suspensions with higher TSS. Under most conditions, total scattering was dominated by inorganic particles. However, the combined effects of other components (the water itself, colored dissolved organic matter, phytoplankton, plus non-algal organic solids) typically dominated both absorption and attenuation. The importance of phytoplankton and organic solids relative to inorganic solids from land runoff have important ramifications for water clarity management, specifically suggesting revaluation of strategies solely focused on reducing inorganic sediment input. Even with an advanced video-settling column (e.g. PICS), there are issues resolving smaller flocs and sampling very low TSS. A major challenge in processing particle images is correctly identifying and sizing particles of varying composition and size, while correctly separating in-focus particles from out-of-focus particles. A new automated analysis approach was created that efficiently resolves particles, while rejecting out-of-focus objects, and was implemented into the automated processing algorithm for the PICS. Field- and laboratory-based experiments were conducted to evaluate video-based size, settling velocity, and density estimates, and it was found that all three parameters were adequately measured with the PICS.

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Koivuranta, E. (Elisa). "Optical monitoring of flocs and filaments in the activated sludge process". Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526211794.

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Abstract Flocculation plays a critical role in the activated sludge process, where flocs are removed by settling and where unsatisfactory flocculation is resulting in poor effluent quality. Control and operation of the process is also challenging as it is sensitive to external and internal disturbances. Furthermore, stricter environmental demands are also being placed on wastewater treatment and discharge quality thus solutions are needed to improve the current systems. A novel optical monitoring method employing a tube flow and a CCD camera was developed to characterize the flocs and filaments of the sludge, and the method was tested on samples from full-scale activated sludge plants. An online device operating on the same principle was also developed and this was tested over a period of eight months at municipal wastewater treatment plant. Optical monitoring was employed in the laboratory to study the breakage of activated sludge flocs. Based on the image analysis data, in the industrial plant the major breakage process was large-scale fragmentation. In the two municipal plants, it was surface erosion. The flocs had more filaments and were more irregular in shape in the industrial plant, which could be the reason for the large-scale fragmentation. The effect of floc morphology on the effluent clarity of the activated sludge process was studied in the industrial and municipal activated sludge plants by optical monitoring over periods of three months and eight months, respectively. The changes in floc morphology took place slowly in both plants. Four major factors that correlated with the purification results were the size and shape of the flocs and the quantities of small particles and filaments. The image analysis results suggested that the settling problem that occurred during the test periods in the industrial plant was caused by dispersed growth, whereas that in the municipal plant was caused by filamentous bulking. In conclusion, it is possible to use the developed method online in order to analyse the state of flocculation. Thus the method could be useful when developing online monitoring applications for quantifying floc characteristics and for diagnosing the causes of settling problems in the wastewater treatment plants
Tiivistelmä Aktiivilieteprosessissa flokkulaatiolla on merkittävä rooli, sillä muodostuneet flokit poistetaan prosessista laskeutuksen avulla. Siten huono flokkulaatio johtaa puhdistetun jäteveden kiintoainemäärän lisääntymiseen. Prosessin säätö ja operointi on kuitenkin hankalaa, sillä aktiivilieteprosessi on herkkä ulkoisille ja sisäisille häiriöille. Jätevedenpuhdistukseen liittyvät ympäristövaatimukset ja päästöehdot vesistöihin ovat myös tiukentuneet, joten uusia menetelmiä tarvitaan parantamaan nykyisiä prosesseja. Tässä työssä kehitettiin uusi, optinen kuvantamismenetelmä karakterisoimaan flokkeja ja rihmoja. Menetelmä hyödyntää putkivirtausta ja CCD-kameraa ja sitä testattiin aktiivilietelaitosten näytteillä. Lisäksi kehitettiin samaa periaatetta noudattava online-laitteisto, jota testattiin kahdeksan kuukauden ajan. Optista kuvantamista testattiin laboratoriossa flokkien hajoamistutkimuksessa. Kuva-analyysitulosten perusteella kahden kunnallisen aktiivilietelaitoksen flokit hajosivat pintaeroosioon perustuvan mallin mukaan ja teollisen aktiivilietelaitoksen flokit hajosivat fragmentaatiomallin mukaan. Teollisen aktiivilietelaitoksen flokeissa oli enemmän rihmoja ja ne olivat epäsäännöllisemmän muotoisia, mikä voi olla syynä flokkien fragmentaatioon. Flokkien morfologian vaikutus jäteveden puhdistustuloksiin tutkittiin teollisessa (kolmen kuukauden ajan) ja kunnallisessa (kahdeksan kuukauden ajan) aktiivilietelaitoksessa optisella kuvantamismenetelmällä. Molemmissa laitoksessa muutokset flokkien morfologiassa tapahtuivat hitaasti. Neljä tärkeintä tekijää, jotka korreloivat puhdistustulosten kanssa, olivat flokkien koko ja muoto sekä pienten partikkelien ja rihmojen määrä. Kuva-analyysitulosten perusteella laskeutumisongelma teollisessa jätevesilaitoksessa johtui flokinmuodostajabakteerien liian pienestä määrästä ja kunnallisessa jätevesilaitoksessa rihmamaisten bakteerien liikakasvusta. Yhteenvetona voidaan todeta, että kehitettyä menetelmää on mahdollista käyttää online-mittarina sekä sen avulla voidaan arvioida flokkulaation tilannetta. Siten menetelmää on mahdollista hyödyntää flokkien ominaisuuksien karakterisoinnissa ja arvioidessa jätevedenkäsittelylaitoksen laskeutumisongelmien aiheuttajaa

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Andrew, Philip L. "Experimental and numerical investigations of the off-design flow physics in a supersonic through-flow fan cascade". Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-07282008-134047/.

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Sutapa, Ignasius Dwi Atmana. "Propriétés physico-chimiques et décantabilité des boues activées en relation avec le transfert d'oxygène et la biofloculation". Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL068N.

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L’aération et la séparation des boues activées constituent les deux étapes clé pour le bon fonctionnement d'une station d'épuration. L’objectif de ce travail est double: caractériser les paramètres susceptibles d'influencer le processus de transfert d'oxygène dans le milieu de boues activées, et étudier l'aptitude à décanter de celles-ci en relation avec la biofloculation mise en jeu. L’étude du transfert d'oxygène montre que le facteur alpha dépend du degré d'épuration de la pollution introduite: ce facteur augmente lorsque la DCO et donc le OUR dans le milieu de culture diminuent. Mais le facteur prépondérant est la concentration en biomasse dans le bassin d'aération: plus cette concentration augmente, plus la viscosité du milieu est importante et plus le facteur alpha diminue. L’étude des flocs de boues activées montre qu'ils présentent une structure très complexe dans laquelle les micro-organismes sont piégés par une matrice de polymères exocellulaires. Ceux-ci, dont les exopolysaccharides, jouent un rôle important dans l'agglomération des micro-organismes. Les expériences montrent que les flocs biologiques placés dans des conditions de famine aérobie, défloculent en relargant des exopolymères dans le milieu interstitiel. Ces conditions de famine permettent, en outre, de supprimer les germes filamenteux, responsables d'une mauvaise décantation

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Libri sul tema "Floc properties"

Lee, Boon Chong. The influence of nutrients on floc physicochemical properties and structure in activated sludge processes. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1999.

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Scott, Heather Elizabeth. The effect of physicochemical properties of microbial floc on UV disinfection of secondary wastewater. Ottawa: National Library of Canada, 2002.

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Whittaker, Dean. The effect of phosphorus on-phosophorus metabolism, metals accumulation and floc properties in activated sludge processes. Ottawa: National Library of Canada, 2002.

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Whiskens, Mark. The flow properties of ceramic pastes. Birmingham: University of Birmingham, 1996.

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Dai, Hongwei. Settling properties of activated sludge flocs. Ottawa: National Library of Canada, 1993.

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V, Ponomarev S. Measurements of thermophysical properties by laminar flow methods. New York: Begell House, 2001.

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V, Ponomarev S. Measurement of thermophysical properties by laminar flow methods. New York: Begell House, 2000.

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Hermsmeyer, Stephan. Improved methods for modelling turbine engine gas flow properties. Birmingham: University of Birmingham, 1996.

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Ahmed, Tarek H. Working guide to reservoir rock properties and fluid flow. Amsterdam: Elsevier, 2010.

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Nagnibeda, Ekaterina A. Transport properties of NO in nonequilibrium flows. Noordwijk, The Netherlands: ESA Publications Division, 2005.

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Capitoli di libri sul tema "Floc properties"

Droppo, I. G., G. G. Leppard, D. T. Flannigan e S. N. Liss. "The Freshwater Floc: A Functional Relationship of Water and Organic and Inorganic Floc Constituents Affecting Suspended Sediment Properties". In The Interactions Between Sediments and Water, 43–53. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5552-6_5.

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Gooch, Jan W. "Flow Properties". In Encyclopedic Dictionary of Polymers, 316. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_5143.

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Hylton, Donald C. "Viscous Flow Properties". In Understanding Plastics Testing, 45–60. München: Carl Hanser Verlag GmbH & Co. KG, 2004. http://dx.doi.org/10.3139/9783446412859.005.

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Wolf, Bettina. "Chocolate flow properties". In Beckett's Industrial Chocolate Manufacture and Use, 274–97. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781118923597.ch11.

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Shenoy, Aroon V. "Extensional flow properties". In Rheology of Filled Polymer Systems, 395–415. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9213-0_9.

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Chevalley, J. "Chocolate flow properties". In Industrial Chocolate Manufacture and Use, 139–55. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2111-2_10.

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Ringrose, Philip, e Mark Bentley. "Upscaling Flow Properties". In Reservoir Model Design, 115–49. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-007-5497-3_4.

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Ringrose, Philip, e Mark Bentley. "Upscaling Flow Properties". In Reservoir Model Design, 131–64. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70163-5_4.

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Ritoré, Manuel, e Carlo Sinestrari. "Invariance properties". In Mean Curvature Flow and Isoperimetric Inequalities, 16–19. Basel: Birkhäuser Basel, 2010. http://dx.doi.org/10.1007/978-3-0346-0213-6_5.

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Beck, A. E. "Thermal Properties". In Handbook of Terrestrial Heat-Flow Density Determination, 87–165. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2847-3_4.

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Atti di convegni sul tema "Floc properties"

Qiu, Tianshuang, Yong Zhu, Saiyuan Zhao e Daifeng Zha. "The Properties of FLOC and Its Application in Evoked Potential Latency Change Detection". In 2008 3rd International Conference on Innovative Computing Information and Control. IEEE, 2008. http://dx.doi.org/10.1109/icicic.2008.567.

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DJORDJEVIC, V., S. PAVITHRAN e L. REDEKOPP. "Stability properties of subsonic mixing layers". In 2nd Shear Flow Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-1020.

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LAO, LIYUN, e MARVELOUS AGUNLOYE. "PHYSICAL PROPERTIES OF WATER–OIL MIXTURES INVOLVING WAXING". In MULTIPHASE FLOW 2017. Southampton UK: WIT Press, 2017. http://dx.doi.org/10.2495/mpf170081.

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Hernández-Pérez, V., L. A. Abdulkareem e B. J. Azzopardi. "Effects of physical properties on the behaviour of Taylor bubbles". In MULTIPHASE FLOW 2009. Southampton, UK: WIT Press, 2009. http://dx.doi.org/10.2495/mpf090301.

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Bisantino, T., P. Fischer, F. Gentile e G. Trisorio Liuzzi. "Rheological properties and debris-flow modeling in a southern Italy watershed". In DEBRIS FLOW 2010. Southampton, UK: WIT Press, 2010. http://dx.doi.org/10.2495/deb100201.

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Lou, H., F. Alvi, C. Shih, J. Choi e A. Annaswamy. "Flowfield Properties of Supersonic Impinging Jets with Active Control". In 1st Flow Control Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2002. http://dx.doi.org/10.2514/6.2002-2728.

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Tanaka, Masa-aki. "Mechanical Properties of Carbon Nanotubes / Hydroxyapatite Composites Prepared by Spark Plasma Sintering". In FLOW DYNAMICS: The Second International Conference on Flow Dynamics. AIP, 2006. http://dx.doi.org/10.1063/1.2204536.

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Yamamoto, G. "Route to the Synthesis of Binder-Free SWCNT Solids with Enhanced Mechanical Properties". In FLOW DYNAMICS: The Second International Conference on Flow Dynamics. AIP, 2006. http://dx.doi.org/10.1063/1.2204535.

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Fukunaga, Masataka. "Some Properties of the Fractional Equation of Continuity and the Fractional Diffusion Equation". In FLOW DYNAMICS: The Second International Conference on Flow Dynamics. AIP, 2006. http://dx.doi.org/10.1063/1.2204557.

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Felekis, Theodoros. "Functionalized Water-Soluble Multi-Walled Carbon Nanotubes: Synthesis, Purification and Length Separation by Flow Field-Flow Fractionation". In ELECTRONIC PROPERTIES OF NOVEL NANOSTRUCTURES: XIX International Winterschool/Euroconference on Electronic Properties of Novel Materials. AIP, 2005. http://dx.doi.org/10.1063/1.2103864.

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Rapporti di organizzazioni sul tema "Floc properties"

Patel, Reena. Complex network analysis for early detection of failure mechanisms in resilient bio-structures. Engineer Research and Development Center (U.S.), giugno 2021. http://dx.doi.org/10.21079/11681/41042.

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Bio-structures owe their remarkable mechanical properties to their hierarchical geometrical arrangement as well as heterogeneous material properties. This dissertation presents an integrated, interdisciplinary approach that employs computational mechanics combined with flow network analysis to gain fundamental insights into the failure mechanisms of high performance, light-weight, structured composites by examining the stress flow patterns formed in the nascent stages of loading for the rostrum of the paddlefish. The data required for the flow network analysis was generated from the finite element analysis of the rostrum. The flow network was weighted based on the parameter of interest, which is stress in the current study. The changing kinematics of the structural system was provided as input to the algorithm that computes the minimum-cut of the flow network. The proposed approach was verified using two classical problems three- and four-point bending of a simply-supported concrete beam. The current study also addresses the methodology used to prepare data in an appropriate format for a seamless transition from finite element binary database files to the abstract mathematical domain needed for the network flow analysis. A robust, platform-independent procedure was developed that efficiently handles the large datasets produced by the finite element simulations. Results from computational mechanics using Abaqus and complex network analysis are presented.

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Taylor, Oliver-Denzil, Amy Cunningham,, Robert Walker, Mihan McKenna, Kathryn Martin e Pamela Kinnebrew. The behaviour of near-surface soils through ultrasonic near-surface inundation testing. Engineer Research and Development Center (U.S.), settembre 2021. http://dx.doi.org/10.21079/11681/41826.

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Seismometers installed within the upper metre of the subsurface can experience significant variability in signal propagation and attenuation properties of observed arrivals due to meteorological events. For example, during rain events, both the time and frequency representations of observed seismic waveforms can be significantly altered, complicating potential automatic signal processing efforts. Historically, a lack of laboratory equipment to explicitly investigate the effects of active inundation on seismic wave properties in the near surface prevented recreation of the observed phenomena in a controlled environment. Presented herein is a new flow chamber designed specifically for near-surface seismic wave/fluid flow interaction phenomenology research, the ultrasonic near-surface inundation testing device and new vp-saturation and vs-saturation relationships due to the effects of matric suction on the soil fabric.

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Kim, H. Local properties of countercurrent stratified steam-water flow. Office of Scientific and Technical Information (OSTI), ottobre 1985. http://dx.doi.org/10.2172/6402013.

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Poggio, Tomaso, Alessandro Verri e Vincent Torre. Green Theorems and Qualitative Properties of the Optical Flow. Fort Belvoir, VA: Defense Technical Information Center, aprile 1991. http://dx.doi.org/10.21236/ada241137.

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Smith III, F. G., e G. P. Flach. Development and Demonstration of Material Properties Database and Software for the Simulation of Flow Properties in Cementitious Materials. Office of Scientific and Technical Information (OSTI), marzo 2015. http://dx.doi.org/10.2172/1178650.

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Lee, I. Y., R. L. Coulter, H. M. Park e J. H. Oh. Numerical simulation of nocturnal drainage flow properties in a rugged canyon. Office of Scientific and Technical Information (OSTI), maggio 1994. http://dx.doi.org/10.2172/10148833.

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Schwegler, E., J. Reed, E. Lau, D. Prendergast, G. Galli, J. Grossman e G. Cicero. The Properties of Confined Water and Fluid Flow at the Nanoscale. Office of Scientific and Technical Information (OSTI), marzo 2009. http://dx.doi.org/10.2172/950072.

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Stephen C. Ruppel. Multidisciplinary Imaging of Rock Properties in Carbonate Reservoirs for Flow-Unit Targeting. Office of Scientific and Technical Information (OSTI), ottobre 2003. http://dx.doi.org/10.2172/897645.

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Ketsdever, Andrew D., Dean C. Wadsworth, Stephen E. Vargo e E. P. Muntz. Flow Properties of a Free Molecule Micro-Resistojet for Small Spacecraft Applications. Fort Belvoir, VA: Defense Technical Information Center, marzo 1998. http://dx.doi.org/10.21236/ada397996.

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Stephen C. Ruppel. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING. Office of Scientific and Technical Information (OSTI), luglio 2004. http://dx.doi.org/10.2172/829801.

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