Treatment of stormwater to bathing water quality by dissolved air flotation, filtration and ultraviolet disinfection

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.

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Treatment of stormwater to bathing water quality by dissolved air flotation, filtration and ultraviolet disinfection

Water Science & Technology ◽

10.2166/wst.1998.0385 ◽

1998 ◽

Vol 38 (10) ◽

pp. 99-105 ◽

Cited By ~ 4

Author(s):

S. Lainé ◽

T. Poujol ◽

S. Dufay ◽

J. Baron ◽

P. Robert

Keyword(s):

Oxygen Demand ◽

Uv Disinfection ◽

Stormwater Treatment ◽

Urban Stormwater ◽

Residual Concentration ◽

Dissolved Air Flotation ◽

Bathing Water ◽

Air Flotation ◽

Pollution Removal ◽

Bathing Water Quality

For the first time, a process for the treatment of urban stormwater has been designed in order to obtain treated water suitable for bathing activities. The degree of pollution removal is taken as far as the microbiological disinfection of the final effluent. This process, which combines air flotation, filtration and ultraviolet (UV) disinfection, has been tested at the pilot plant level in the eastern suburbs of Paris, France. The removal efficiency obtained on total suspended solids (TSS) and chemical oxygen demand (COD) through the flotation stage is close to 90% or better. The flotation facility has proved to be perfectly adapted to urban stormwater treatment with a maximal efficiency in the first minute of operation and with a TSS residual concentration consistently about 45 mg/L regardless of the variations in polluting loads entering the process. This is essential when taking into consideration the extreme variability of this load during rainfall. Sand filtration with a continuous washing system prevents operational interruptions during rainfall events. The UV disinfection process allows the microbiological contamination of the effluent to be reduced to a level in compliance with the regulations that define the quality of bathing water.

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A decade of large scale experience in dissolved air flotation

Water Science & Technology ◽

10.2166/wst.2001.0456 ◽

2001 ◽

Vol 43 (8) ◽

pp. 27-34 ◽

Cited By ~ 12

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.

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

Water Science & Technology ◽

10.2166/wst.2007.771 ◽

2007 ◽

Vol 56 (10) ◽

pp. 149-155 ◽

Cited By ~ 9

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.

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

Water Science & Technology ◽

10.2166/wst.2003.0141 ◽

2003 ◽

Vol 48 (2) ◽

pp. 357-364 ◽

Cited By ~ 5

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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Water clarification with natural coagulants and dissolved air flotation

Waterlines ◽

10.3362/0262-8104.1986.044 ◽

1986 ◽

Vol 5 (2) ◽

pp. 23-26 ◽

Cited By ~ 2

Author(s):

Folkard ◽

Sutherland ◽

Jahn

Keyword(s):

Dissolved Air Flotation ◽

Natural Coagulants ◽

Air Flotation ◽

Dissolved Air

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Behaviour of air injection nozzles in dissolved air flotation

Water Science & Technology ◽

10.2166/wst.1995.0513 ◽

1995 ◽

Vol 31 (3-4) ◽

pp. 25-35 ◽

Cited By ~ 12

Author(s):

E. M. Rykaart ◽

J. Haarhoff

Keyword(s):

Bubble Coalescence ◽

Second Phase ◽

Initial Growth ◽

Two Phase ◽

Dissolved Air Flotation ◽

Nozzle Orifice ◽

Pressure Release ◽

Air Volume ◽

Air Flotation ◽

Dissolved Air

A simple two-phase conceptual model is postulated to explain the initial growth of microbubbles after pressure release in dissolved air flotation. During the first phase bubbles merely expand from existing nucleation centres as air precipitates from solution, without bubble coalescence. This phase ends when all excess air is transferred to the gas phase. During the second phase, the total air volume remains the same, but bubbles continue to grow due to bubble coalescence. This model is used to explain the results from experiments where three different nozzle variations were tested, namely a nozzle with an impinging surface immediately outside the nozzle orifice, a nozzle with a bend in the nozzle channel, and a nozzle with a tapering outlet immediately outside the nozzle orifice. From these experiments, it is inferred that the first phase of bubble growth is completed at approximately 1.7 ms after the start of pressure release.

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

Water Science & Technology ◽

10.2166/wst.1998.0098 ◽

1998 ◽

Vol 37 (2) ◽

pp. 35-42 ◽

Cited By ~ 5

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.

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