Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"settleability"”.
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Post precipitation treatment of copper sulphide particles to improve settleability
… on the effect of dissolved lattice ions on settleability were performed.
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Improving settleability and achieving biological phosphorus removal through the application of sidestream gravimetric selectors
… a full-scale plant for the purpose of increased settleability, while also achieving enhanced biological phosphorus removal without the use of an anaerobic selector. Hydrocyclones receive mixed liquor tangentially and separate light solids from more dense solids through their tapered shape, …
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The effects of dissolved oxygen concentration on the kinetics and settleability of activated sludge
… concentration affect the kinetic coefficient and settleability of activated sludge. Synthetic substrate loadings of 0.25, 0.50, 0.75 were applied to bench scale activated sludge reactors with average mixed liquor volatile suspended solids concentrations of 2000 mg/1. The substrate removal rate …
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Improving the settleability of a metal sulphide suspension by the application of a magnetic field
Gravitational sedimentation of suspensions in various precipitation processes is hindered by colloidal stability. More especially in sulphide precipitation, where high levels of supersaturation dominate and nucleation is favoured. This results in a large number of colloidal particles with a highly …
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Temporal biomass density and filamentous bacteria effects on secondary settling
… The effects of variable biomass density on settleability of biosolids produced in full scale activated sludge wastewater treatment systems has been recently been demonstrated, and seasonal variability in biomass settleability is known to occur at many wastewater treatment plants. The role of …
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Gravity selector-enabled kenaf recirculation and reuse as a renewable ballasting agent for sludge settleability enhancement in a municipal wastewater secondary process: A real wastewater pilot-scale study
… during flocculant settling contributed to the settleability improvements. However, a lack of biofilm formation on the kenaf surface was observed even after 110 days of treatment is intriguing and different from other studies. Challenges with initial kenaf floating and interference with …
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TREATMENT OF PETROLEUM REFINERY WASTEWATER IN AN INNOVATIVE SEQUENCING BATCH REACTOR
The difficulty with sludge settleability is considered one of the main drawbacks of sequencing batch reactors. The aim of this study therefore is to improve sludge settleability by introducing a novel, two-stage settling sequencing batch reactor (TSSBR) separated by an anoxic stage. The performance …
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Operational parameters of the filamentous microbial process
… parameters of the FAS process. Specifically: the settleability of filamentous sludge produced by the treatment system, the yield coefficient of the biological population, and the carbon to phosphorus ratio which limits organic removal efficiency. Findings of this study indicate that the sludges …
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The effect of the type, size, position and recycle ratio of the anoxic zone on low F/M filament bulking in nitrogen removal activated sludge systems
… bulking, which causes deterioration in sludge settleability has been shown, in two nation-wide surveys to be a problem of considerable proportions. Poor sludge settleability in the secondary clarifier limits the daily flow and load that can be treated in activated sludge wastewater treatment …
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The effect of a large anoxic mass fraction and concentrations of nitrate and nitrite in the primary anoxic zone on low f/m filament bulking in nutrient removal activated sludge systems
… floes. This results in a sludge with poor settleability i.e., low settling velocity and low solids concentration in the return activated sludge (RAS). In severe cases overflow of the sludge with the effluent occurs. Bulking not only causes these problems in the activated sludge process, but …
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Hydrocyclone Implementation at Two Wastewater Treatment Facilities To Promote Overall Settling Improvement
… treatment facilities experiencing poor settleability. Hydrocyclones are fed mixed liquor through the feed inlet and experience a centrifugal motion that separates solids based on density. The variation in hydrocyclone nozzle sizes will report different calculated hydraulic and mass split …
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The effects of rapid mixing on the coagulation and sedimentation of ultra-fine coal and clay particles
… of coagulant addition and rapid mixing on the settleability of these particles. After initial testing, aluminum sulfate and two low molecular weight cationic polymers, Cyanamid Magnifloc 513C and Cyanamid 515C, were chosen as primary coagulants for use in this work. An artificial wastewater was …
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The effect of temperature on denitrification kinetics and biological excess phosphorus removal in nutrient removal activated sludge systems in temperate climates (12°C - 20°C)
… have bulking sludges to the extent that sludge settleability (DSVI) was adversely affected. If filamentous organism proliferation could be controlled and thereby sludge settleability improved to below DSVI of 100 ml/g, then with provision for factors such as additional aeration capacity, between …
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Physical and biological factors affecting oxygen transfer in the activated sludge wastewater treatment process
… specific filament length (SFL), 30 min settleability (SV<sub>30</sub>), etc., does influence the OTE. Filamentous organisms increase the hydrodynamic radius of suspended particles, which dilates mixed liquor apparent viscosity (µ<sub>app</sub>) and impedes mass transfer. For example, an …
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An investigation of the effects of the addition of powdered activated carbon to the activated sludge of cellulose acetate manufacturing wastewater
… The addition of PAC also improved the sludge settleability but this resulted in higher effluent suspended solids concentration because zone settling Velocity was the primary factor affecting effluent suspended solids. A type of activated sludge bulking, known as jelly formation, plagued the …
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The effects of pH on aerobic sludge digestion
… with lower pH. Striking improvement in the settleability, drainability and filterability of sludge digested at pH 3.5 occurred. This effect was attributed to the development of an - overwhelming protozoan population which caused observed improvement in the flocculation characteristics of the …
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Bioflocculation of Wastewater Treatment Pond Suspended Solids
… then was allowed to settle to assess settleability. Conventionally, microalgal suspended solids are removed by chemical coagulation followed by separation methods that often have a high cost relative to the low cost lagoon or HRAP system where the solids were produced. This separation …
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Mathematical simulation of dynamic behaviour of secondary settling tanks
… constants may be derived from simpler sludge settleability measures; and secondly, by developing a computer model for the simulation of dynamic behaviour of full scale secondary settling tanks. The model was initially developed for and tested on laboratory scale data. It was then calibrated …
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The effect of nitrite and nitrate concentrations on low F/M filament bulking in nitrogen removal activated sludge systems
… bulking and its associated poor sludge settleability is a considerable problem in South African activated sludge plants, as indicated by the two surveys undertaken on these plants in 1985 and 1988 (Blackbeard et al., 1986, 1988). Amelioration of this problem would enable a greater daily …
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Zooplankton Dynamics in Wastewater Treatment High Rate Algal Ponds and development of effective control methods
… spines in microalgae; and higher biomass settleability. Maintaining a dominance of colonial microalgae, operating HRAPs with short retention times, and facilitating competition among zooplankton species showed to potentially reduce grazer populations. Promising options for zooplankton …
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