Application of the flotation process to thicken the sludge from a DAF plant

2006 ◽  
Vol 53 (7) ◽  
pp. 159-165 ◽  
Author(s):  
S. Dockko ◽  
S.C. Park ◽  
S.B. Kwon ◽  
M.Y. Han
Keyword(s):  
Treatment Plant ◽  
Water Treatment Plant ◽  
Total Solid ◽  
Solid Concentration ◽  
Dissolved Air Flotation ◽  
Flotation Process ◽  
Withdrawal Velocity ◽  
Gravity Thickening ◽  
The Relationship ◽  
Dissolved Air

Dissolved air flotation (DAF) was evaluated for thickening of the sludges from a water treatment plant which uses DAF. Solid flux theory for gravity thickening was applied to the solid flux of DAF sludge. The higher the polymer dosage, at fixed solid concentration, the greater the rising velocity becomes. When applied with solid flux equations, a similar relationship to that of gravity thickening has been found. However, the values were much higher than in gravity thickening, because both the inflow solid concentration and the floating velocity were higher than for settled sludge. With this result, the proper dosage of polymer could be derived from the relationship between total solid flux and withdrawal velocity of DAF sludge.

Using lessons learned and advanced methods to design a 1,500 Ml/day DAF water treatment plant

2001 ◽  
Vol 43 (8) ◽  
pp. 35-41 ◽  
Author(s):  
I. A. Crossley ◽  
M. T. Valade ◽  
J. Shawcross
Keyword(s):  
Fluid Dynamics ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Lessons Learned ◽  
Plant Design ◽  
Dissolved Air Flotation ◽  
Computational Fluid Dynamics Cfd ◽  
Solids Removal ◽  
Dissolved Air

The paper describes the method that led to the design of the 1,500 Ml/day dissolved air flotation (DAF) water treatment plant for Boston's water supply. In particular, the topics of flocculation techniques, floated solids removal and DAF recycle as they relate to very large capacity plant design are covered in detail. The use of mathematical models, including computational fluid dynamics (CFD) software, to refine the design is described.

Birmingham Frankley water treatment works redevelopment

1995 ◽  
Vol 31 (3-4) ◽  
pp. 213-223
Author(s):  
T. Schofield
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Main Stage ◽  
Process Stream ◽  
Dissolved Air Flotation ◽  
Treatment Facilities ◽  
Selection Of ◽  
Design Construction ◽  
Dissolved Air

Severn Trent Water are currently undertaking an extensive capital programme to enhance water treatment facilities at many of its major works. This paper describes the various aspects of the Birmingham Water Treatment Plant Redevelopment Strategy with specific emphasis on the factors that lead to the selection of dissolved air flotation (DAF) as a main stage of clarification and subsequent construction of the largest DAF plant in the world. The design, construction and operation of the plant are reviewed with particular attention to water quality and the use of carbon dioxide within the process stream to produce a stable treated water.

The first DAF water treatment plant in the United States

1995 ◽  
Vol 31 (3-4) ◽  
pp. 239-246 ◽  
Author(s):  
David Nickols ◽  
Gerard C. Moerschell ◽  
Michael V. Broder
Keyword(s):  
United States ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
The United States ◽  
Regulatory Body ◽  
Process Selection ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air

The Millwood Water Treatment Plant in Westchester County, about 60 kilometres (35 miles) north of New York City, was commissioned in August 1993. This plant is the first dissolved air flotation (DAF) plant in the United States which uses the DAF technology and concepts that have become the industry standards in Europe and Australia. The $19-million plant was built to treat a previously unfiltered supply, to meet the requirements of the new federal Surface Water Treatment Rule. This paper describes the project in its entirety: starting from the planning, pilot testing, and process selection; proceeding to the means of overcoming resistance to a “new” process and obtaining regulatory body approvals; and outlining the design, process criteria, construction, and start-up of the plant. Operating results are also presented. The plant treats soft, slightly colored, generally low turbidity water which experiences occasional turbidity spikes of 100 NTU or more. The treatment process comprises two-stage mixing, three-stage flocculation, dissolved air flotation, ozonation for primary disinfection, dual-media filtration, and post-treatment with chlorine, sodium hydroxide, orthophosphate and fluoride. Flotation sludge is dewatered in on-site freeze/thaw lagoons for off-site disposal in a landfill.

Optimising dissolved air flotation/filtration treatment of algae-laden lagoon effluent using surface charge: a Bolivar treatment plant case study

2012 ◽  
Vol 66 (8) ◽  
pp. 1684-1690 ◽  
Author(s):  
Russell Yap ◽  
Michael Holmes ◽  
William Peirson ◽  
Michael Whittaker ◽  
Richard Stuetz ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Surface Charge ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
A Charge ◽  
Dissolved Air

Dissolved air flotation (DAF) incorporating filtration (DAFF) is used at the Bolivar wastewater treatment plant (WWTP) to polish lagoon effluent for reuse. Elevated algal populations are frequently experienced and can lead to increased coagulant requirements and process control issues. Streaming current detectors (SCDs) and a charge demand analyser (CDA) were used to monitor the full-scale plant. This was followed by an optimisation study using a pilot plant with a CDA. It was found that the normal operational charge demand range for DAF at Bolivar was between −46 and −40 μeq L−1. Decreasing the pH of coagulation reduced coagulant consumption and facilitated more sensitive CDA responses to changes in alum dose.

Effect of surfactant on alum sludge conditioning and dewaterability

2000 ◽  
Vol 41 (8) ◽  
pp. 17-22 ◽  
Author(s):  
J. Ruhsing Pan ◽  
C. Huang ◽  
C. Gang Fu
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Flotation Process ◽  
Polymer Addition ◽  
Sludge Disposal ◽  
Alum Sludge ◽  
Sludge Conditioning ◽  
Increasing Demand ◽  
Co Precipitation

Sludge disposal has become a new challenge for the Taiwan government due to the increasing demand for better quality and greater quantity of water. In some water treatment plants, surfactant has been applied in the flotation process to improve its performance, which suggests the use of surfactant in sludge conditioning. In this study, effects of surfactants on the conditioning of the alum sludge collected from Feng-Yuan Water Treatment Plant were investigated. Surfactants of various charges, namely CTAB and SDS, were added to sludge samples in various amounts, and their effects on sludge dewaterability were evaluated. Surfactants were also added with either cationic or anionic polymers to better understand their effects on the mechanism of sludge conditioning and the feasibility as coagulant aid.Experimental results indicate that applying surfactants alone in sludge system decrease the filterability of sludge, but increase the sludge dewatering rate at optimum dosage. Cationic surfactant was proven possible as conditioning aid for the cationic polymer. The order of surfactant and polymer addition is the key to additive function. On the other hand, when the polymer of opposite charge was added with the surfactant, co-precipitation occurred which resulted in decreased filterability and dewaterability.

Removal of clay and blue-green algae particles through zeta potential and particle size distribution in the dissolved air flotation process

2006 ◽  
Vol 6 (1) ◽  
pp. 95-103 ◽  
Author(s):  
D.H. Kwak ◽  
S.J. Kim ◽  
H.J. Jung ◽  
C.H. Won ◽  
S.B. Kwon ◽  
...  
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Green Algae ◽  
Dissolved Air Flotation ◽  
Flotation Process ◽  
Clay Particles ◽  
Blue Green Algae ◽  
Dissolved Air

The raw water characteristics of a water treatment plant in Korea are mainly dependent on two major factors: the clay particles attributed to rainfall and blue-green algae in reservoirs. In this work, zeta potential and particle size distributions of clay and algae particles, which are the important parameters affecting their removal efficiency, were measured to investigate the behavior and removal characteristics of particles under various conditions. The results showed that the zeta potential of blue-green algae was more sensitive to treatment conditions than clay, and it fluctuated highly with coagulant dosage, suggesting that the control of zeta potential is important for effective removal of algae particles. On the other hand, the range of particle size distribution that remained from the preliminary sedimentation tank was generally smaller than for flotation. However, the zeta potential of the remaining particles was either close to the isoelectric point or positive, and the particles were not so hard to remove for that reason. In the final analysis, for simultaneous removal of clay and algae particles, a sufficient zeta potential difference must be formed not only for algae particles but also for small clay particles from the sedimentation tank in the dissolved air flotation process.

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