Comparative Study of Dissolved Air Flotation and Sedimentation Process for Treating Reservoir Water with Low Temperature, Low Turbidity and High Natural Organic Matter

2011 ◽  
Vol 71-78 ◽  
pp. 2767-2771 ◽  
Author(s):  
Jing Zou ◽  
Jun Tao Zhu ◽  
Chao Pan ◽  
Jun Ma
Keyword(s):  
Water Quality ◽  
Low Temperature ◽  
Bubble Column ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Sedimentation Process ◽  
Air Flotation ◽  
Better Than ◽  
Glass Bubble ◽  
Dissolved Air

In this research, the dissolved air flotation (DAF) were tried to treat drinking water to replace traditional sedimentation technology. Experimental study of sedimentation process and DAF was carried out in a jet tester and a glass bubble column respectively. The experimental results demonstrated that the indicators of water quality such as turbidity, chromaticity and CODMn after two processes decreased firstly and then increased with the PAC-dose increasing, and 7.41 mg Al L-1 was the optimum PAC dosage. Moreover, with the optimum PAC dosage, water quality after DAF proved much better than that after sedimentation process. As a result, DAF is a more effective technology to treat the reservoir water with low temperature, low turbidity and high NOM.

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.

Research on treating algae-polluted reservoir water by the process of pre-oxidation/dissolved air flotation/carbon sand filter

2018 ◽  
Vol 19 (3) ◽  
pp. 823-830 ◽  
Author(s):  
Yonglei Wang ◽  
Wenhao Wang ◽  
Ruibao Jia ◽  
Mei Li ◽  
Baozhen Liu ◽  
...  
Keyword(s):  
Removal Rate ◽  
Water Diversion ◽  
Reflux Ratio ◽  
Reservoir Water ◽  
Combined Process ◽  
Dissolved Air Flotation ◽  
Blue Green Algae ◽  
Operation Conditions ◽  
Air Flotation ◽  
Dissolved Air

Abstract As the water diversion reservoir showed high organic matter and high algae in summer, the potassium permanganate pre-oxidation/dissolved air flotation/carbon sand double filter process was developed. The test results show that the optimum operation conditions of the combined process were as follows: the dosage of KMnO4 was 0.3 mg/L, the dosage of polymeric aluminum ferric chloride (PAFC) was 3.0 mg/L (Al3+), the reflux ratio was 10%, and the dissolved gas pressure was 0.3 Mpa. Taking Ji'nan Queshan reservoir water algae pollution as the research object, the average removal rate of chlorophyll a, blue-green algae, turbidity, particle number and total organic carbon (TOC) reached 66.64%, 95.44%, 94.45%, 99.34% and 46.68%, respectively; the methylisoborneol (MIB) removal rate was 92.47%, the odor level decreased with process flow from raw water level 4 to effluent level 1.5, geosmin (GSM) dropped below the detection limit, and the total removal rate of trihalomethane formation potential (THMFP) was 33.56%. The effluent of the combined process meets the requirements of the Hygienic Standard for Drinking Water (GB5749-2006) after it is disinfected.

The role of particle size and density in dissolved air flotation and sedimentation

1997 ◽  
Vol 36 (4) ◽  
pp. 177-189 ◽  
Author(s):  
A. Vlaški ◽  
A. N. van Breemen ◽  
G. J. Alaerts
Keyword(s):  
Kinetic Modelling ◽  
Single Cells ◽  
Process Efficiency ◽  
Laboratory Model ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Floc Size ◽  
Air Flotation ◽  
G Value ◽  
Dissolved Air

Conventional (sedimentation) and advanced (dissolved air flotation) treatment were studied in the context of removal of the single cells form of the cyanobacteria Microcystis aeruginosa. This cyanobacterium species is recognised as an ideal surrogate for process removal efficiency assessment of particles of the problematic size range (3-10 m). The agglomeration (coagulation/flocculation) phase has been indicated as essential and determining the down-stream process efficiency, hence it is a prerequisite for process improvement. Relevant process parameters have been addressed on a laboratory (model water) and pilot plant (reservoir water) scale, including the influence of coagulant (FeCl3) dose, coagulation pH, flocculation time, energy input (G value), single stage versus tapered flocculation and application of cationic polymer as coagulant aid. The process efficiency was assessed as a function of the preceeding agglomeration (coagulation/flocculation) phase and the obtained particle (floc) size distributions. The particle (floc) size - density relationship was addressed in the context of more accurate process kinetic modelling.

Comparison of dissolved air flotation and direct filtration

1995 ◽  
Vol 31 (3-4) ◽  
pp. 113-124 ◽  
Author(s):  
C. Ferguson ◽  
G. S. Logsdon ◽  
D. Curley
Keyword(s):  
South Carolina ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Direct Filtration ◽  
Flotation Treatment ◽  
Treatment Train ◽  
Air Flotation ◽  
And Control ◽  
Iron And Manganese ◽  
Dissolved Air

Direct filtration with and without pre-ozone, and dissolved air flotation and filtration were evaluated for clarification of high quality reservoir water in Greenville, South Carolina, USA. Goals of the study included production of low turbidity filtered water and control of algae, iron and manganese, and disinfection by-product precursors. The dissolved air flotation treatment train gave much longer filter runs than direct filtration, when both processes met the 0.10 NTU goal for filtered water quality. Use of pre-ozone was beneficial for direct filtration. Removal of TOC, DBP precursors, and iron and manganese were similar for both processes.

A decade of large scale experience in dissolved air flotation

2001 ◽  
Vol 43 (8) ◽  
pp. 27-34 ◽  
Author(s):  
S. Kempeneers ◽  
F. Van Menxel ◽  
L. Gille
Keyword(s):  
Water Quality ◽  
Large Scale ◽  
Mechanical Design ◽  
Operational Experience ◽  
Raw Water ◽  
Dissolved Air Flotation ◽  
The Past ◽  
Air Flotation ◽  
Entire Treatment ◽  
Dissolved Air

In April 1990 Antwerpse Waterwerken brought a new DAF-plant into operation at the production centre Notmeir-Walem. The flotation unit, which has a capacity of 200,000 m3/d, was integrated in one of the two existing treatment lines. Its main objective was to eliminate the important raw water quality fluctuations caused by increasing algal growths. During the past ten years several optimisation studies were carried out which resulted in a further simplification of operation and mechanical design. This paper will focus mainly on the integration of dissolved air flotation in the entire treatment line, the consequences on the dual layer filtration and the operational experience and information gathered during the past decade.

Enhanced separation of water quality parameters in the DAF (Dissolved Air Flotation) system using ozone

2007 ◽  
Vol 56 (10) ◽  
pp. 149-155 ◽  
Author(s):  
Byoung-Ho Lee ◽  
Won-Chul Song ◽  
Hye-Young Kim ◽  
Jeong-Hyeon Kim
Keyword(s):  
Water Quality ◽  
Heterotrophic Bacteria ◽  
Removal Rate ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Water And Wastewater Treatment ◽  
Dissolved Air Flotation ◽  
Micro Bubble ◽  
Air Flotation ◽  
Dissolved Air

Dissolved Air Flotation (DAF) has been used in water and wastewater treatment because it has an excellent separation capability. It was found that the separation capability of the DAF system could be even more enhanced by ozone. Ozone was applied as a substitute for air in the DAF system, so that the system was named as the DOF (Dissolved Ozone Flotation) system. Ozone not only enhances coagulation as is well known, but also provides larger micro-bubble volume because the solubility of ozone in water is much higher than that of air. Ozone enhanced the separation rate of SS by 13.6%, and turbidity by 21% in the DOF system compared to the DAF system. T-P was also removed 7.7% more in the DOF system. 41.5% of color and 7.4% of CODCr were enhanced in their removal rate. Coliform and heterotrophic bacteria were removed 54% and 57.3% more in the DOF system. Separation capability of the DOF system was greatly enhanced for most of the water quality parameters because ozone provides strong oxidation power with large volume of micro-bubbles.

Seasonal influence of waste stabilisation pond effluent on DAF/F (dissolved air flotation/filtration) process operation

2003 ◽  
Vol 48 (2) ◽  
pp. 357-364 ◽  
Author(s):  
F. Buisine ◽  
D. Oemcke
Keyword(s):  
Water Quality ◽  
Seasonal Variations ◽  
Chemical Treatment ◽  
Abiotic Factors ◽  
South Australia ◽  
Algal Population ◽  
Dissolved Air Flotation ◽  
Process Operation ◽  
Air Flotation ◽  
Dissolved Air

The Bolivar wastewater treatment plant (WWTP), North of Adelaide, South Australia encompasses the largest waste stabilisation pond (WSP) system in the Southern hemisphere. The wastewater effluent will ultimately be fully reused for agriculture irrigation. A dissolved air flotation/filtration (DAF/F) plant was installed for tertiary treatment downstream of the stabilisation lagoons for supply to the irrigation scheme. Chemical treatment in the form of coagulation and flocculation is required to assist the separation process. The DAF/F plant operation is highly dependent on the raw water algal population. Seasonal variations seem to be the main abiotic factors affecting the algal population growth. Significant doses of chemical can be required to respond to rapid changes of water quality. United Water International is currently assessing the appropriate chemical treatment for short term response, and is also working with Flinders University of South Australia on determining ways to manage the lagoons and to control the water quality feeding the DAF/F plant in the long term. This paper outlines the effect of seasonal variations of WSP effluent quality on the DAF/F process operation, the findings for an adapted chemical treatment, and the eventual possibilities for lagoon management.

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