Optimization of Fenton's reagent coupled to Dissolved Air Flotation to remove cyanobacterial odorous metabolites and suspended solids from raw surface water

2011 ◽  
Vol 64 (8) ◽  
pp. 1668-1674 ◽  
Author(s):  
Jorge A. Elías-Maxil ◽  
Fotis Rigas ◽  
María Teresa Orta de Velásquez ◽  
Rosa-María Ramírez-Zamora
Keyword(s):  
Water Treatment ◽  
Suspended Solids ◽  
Advanced Oxidation Process ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air

Ferrous salts are commonly used as coagulants in Water Treatment Plants (WTPs). When these salts are combined with hydrogen peroxide in acidic conditions – besides coagulation – an additional Advanced Oxidation Process (Fenton's reagent) can take place. Using a response surface methodology, this paper presents the optimization of a novel treatment system constituted by Fenton's reagent (FE) and Dissolved Air Flotation (DAF) for removing 2-Methylisoborneol (MIB), geosmin and Total Suspended Solids (TSS) from raw water. FE was proven able to remove completely both micro pollutants found in the influent of a drinking water treatment plant. Moreover, higher clarification rate was achieved by coupling FE-DAF with respect FE-Sedimentation.

Principles and applications of dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 1-23 ◽  
Author(s):  
James K. Edzwald
Keyword(s):  
Bubble Formation ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Plant Design ◽  
Dissolved Air Flotation ◽  
Floc Size ◽  
Hydrophobic Particles ◽  
Air Flotation ◽  
The Impact ◽  
Dissolved Air

Principles of dissolved air flotation (DAF) discussed include: bubble formation and size, bubble-particle interactions, measures of supplied air, and modeling of the reaction and clarification zones of the flotation tank. Favorable flotation conditions for bubble attachment or adhesion to particles requires a reduction in the charge of particles and production of hydrophobic particles or hydrophobic spots on particle surfaces. A conceptual model for the bubble-particle reaction zone based on the single collector collision efficiency is summarized and discussed. An alternative modeling approach is considered. Clarification or separation zone modeling is based on particle-bubble agglomerate rise velocities. The application of DAF in drinking water treatment is addressed beginning with summaries of design and operating parameters for several countries. DAF should not be considered as a separate process, but integrated into the design and operation of the overall treatment plant. This concept shows that flocculation ahead of DAF has different requirements regarding floc size and strength compared to sedimentation. The efficiency of DAF in removing particles and reducing particle loads to filters needs to be integrated into DAF plant design. The impact on filtration performance is illustrated. Finally, fundamental and applied research needs are addressed.

Use of dissolved air flotation in potable water treatment in Finland

1995 ◽  
Vol 31 (3-4) ◽  
pp. 225-238 ◽  
Author(s):  
J. Heinänen ◽  
P. Jokela ◽  
T. Ala-Peijari
Keyword(s):  
Water Treatment ◽  
Drinking Water Treatment ◽  
Dissolved Air Flotation ◽  
Unit Process ◽  
Air Bubble ◽  
Special Cases ◽  
Air Flotation ◽  
Practical Experiences ◽  
Dissolved Air

The basic concepts of treating humic waters with dissolved air flotation are discussed emphasizing the important role of zeta potential in the forming of floc-air-bubble-agglomerates. Then practical experiences from Finnish drinking water treatment plants are presented. When surface water is used as a raw water, it is more or less humic. Thirty-six such plants have dissolved air flotation as a clarification process, the oldest one dating from 1965. They serve about one million people. All of them are working well proving that dissolved air flotation is a suitable method in humic water treatment. Some special cases are discussed in detail. These are cases where sufficient data about design, operation and costs are available and which it is hoped can help other designers. The last plant referred to is an example of an advanced treatment process where dissolved air flotation is an integrated unit process.

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.

Enhanced rapid gravity filtration and dissolved air flotation for pre-treatment of river thames reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 35-42 ◽  
Author(s):  
M. J. Bauer ◽  
R. Bayley ◽  
M. J. Chipps ◽  
A. Eades ◽  
R. J. Scriven ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Supply ◽  
21St Century ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Lowland Rivers ◽  
Air Flotation ◽  
Pre Treatment ◽  
Counter Current ◽  
Dissolved Air

Thames Water treats approximately 2800Ml/d of water originating mainly from the lowland rivers Thames and Lee for supply to over 7.3million customers, principally in the cities of London and Oxford. This paper reviews aspects of Thames Water's research, design and operating experiences of treating algal rich reservoir stored lowland water. Areas covered include experiences of optimising reservoir management, uprating and upgrading of rapid gravity filtration (RGF), standard co-current dissolved air flotation (DAF) and counter-current dissolved air flotation/filtration (COCO-DAFF®) to counter operational problems caused by seasonal blooms of filter blocking algae such as Melosira spp., Aphanizomenon spp. and Anabaena spp. A major programme of uprating and modernisation (inclusion of Advanced Water Treatment: GAC and ozone) of the major works is in progress which, together with the Thames Tunnel Ring Main, will meet London's water supply needs into the 21st Century.

Cryptosporidium removal during water treatment using dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 125-135 ◽  
Author(s):  
T. Hall ◽  
J. Pressdee ◽  
R. Gregory ◽  
K. Murray
Keyword(s):  
Water Treatment ◽  
Metal Ion ◽  
Ion Concentration ◽  
Sudden Increase ◽  
Water Turbidity ◽  
Dissolved Air Flotation ◽  
Treatment Processes ◽  
Air Flotation ◽  
The Uk ◽  
Dissolved Air

The occurrence of the protozoan parasite Cryptosporidium parvum in water supplies, and the resultant outbreaks of cryptosporidiosis in the UK and USA, have led to concern over the ability of conventional water treatment processes to remove Cryptosporidia from water sources. Large scale pilot plant trials of water treatment have been carried out in the UK to establish the degree of removal that can be achieved by a range of treatment processes, including dissolved air flotation, and to compare the performance of different treatment options. Results from part of these trials are presented in this paper. These results suggest that well operated chemical coagulation based treatment, using either dissolved air flotation or floc blanket clarification, should be capable of achieving removal of Cryptosporidium oocysts of over 99%. There was no evidence of differences in performance between the different types of filter media investigated. The risk of increased Cryptosporidium concentration in the filtered water will increase as filtrate turbidity increases. However, other factors such as high coagulant metal-ion concentration in the filtered water, or a sudden increase in clarified water turbidity, without any increase in filtered water turbidity, may also indicate treatment problems and associated risk from Cryptosporidia. Recycling of backwash waters may also increase the risk.

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.

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