Stormwater treatment by dissolved air flotation: first results from a pilot project

1995 ◽  
Vol 32 (1) ◽  
pp. 137-143 ◽  
Author(s):  
C. Bernard ◽  
P. Herviou ◽  
T. Poujol

A stormwater treatment plant using dissolved air flotation was operated in 1993, at the outlet of the Chelles River catchment area (Seine-et-Marne, France). The process was divided into two different stages. Firstly, a coagulation/flocculation stage, secondly a flotation stage in a flotation tank. The flow rate was set at 13 m3/h. Stormwater was the main part of the effluent but with some urban wastewater as the network is not strictly separate. The process efficiency was tested for suspended solids, chemical oxygen demand and hydrocarbons. A total hydrocarbon removal was observed. Finally, constant output concentrations were observed in spite of important input roughwater concentration variations.

2012 ◽  
Vol 66 (8) ◽  
pp. 1684-1690 ◽  
Author(s):  
Russell Yap ◽  
Michael Holmes ◽  
William Peirson ◽  
Michael Whittaker ◽  
Richard Stuetz ◽  
...  

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.


1999 ◽  
Vol 40 (8) ◽  
pp. 137-143 ◽  
Author(s):  
R. G. Penetra ◽  
M. A. P. Reali ◽  
E. Foresti ◽  
J. R. Campos

This paper presents the results of a study performed with a lab-scale dissolved-air flotation (LSDAF) unit fed with previously coagulated effluent from a pilot scale up-flow anerobic sludge blanket (UASB) reactor treating domestic sewage. Physical operational conditions for coagulation (rapid mix) and flocculation/flotation were maintained constant. Chemical (FeCl3) dosages ranged from 30 to 110 mg.l−1. The effect of pH was also verified in the range of 5.1 to 7.6 for each dosage. Best results were achieved for 65 mg.l−1 of FeCl3 and pH values between 5.3 and 6.1. For these conditions, the removal efficiencies obtained in the LSDAF unit were: between 87% and 91% for chemical oxygen demand (COD), between 95% and 96% for total phosphate (TP), 94% for total suspended solids (TSS), between 96% and 97% for turbidity (TU), between 90% and 93% for apparent color (AC) and more than 96% for sulfide (S). For the UASB-DAF system, global efficiencies would be around 98% for COD, 98% for TP, 98.4% for TSS, 99.3% for TU and 98% for AC. The stripped gases treatment is desirable.


2011 ◽  
Vol 11 (2) ◽  
pp. 110-122 ◽  
Author(s):  
J. O. Babatola ◽  
K. T. Oladepo ◽  
S. Lukman ◽  
N. O. Olarinoye ◽  
I. A. Oke

1997 ◽  
Vol 36 (4) ◽  
pp. 177-189 ◽  
Author(s):  
A. Vlaški ◽  
A. N. van Breemen ◽  
G. J. Alaerts

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.


1995 ◽  
Vol 31 (3-4) ◽  
pp. 1-23 ◽  
Author(s):  
James K. Edzwald

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.


2003 ◽  
Vol 48 (6) ◽  
pp. 285-293
Author(s):  
R.G. Penetra ◽  
M.A.P. Reali ◽  
J.R. Campos

This paper presents the results of a study performed with an experimental domestic sewage treatment plant (240 m3.d-1 flow) consisting of expanded bed anaerobic reactor (EBAR) followed by dissolved air flotation (DAF) unit. For the flotation step, the anaerobic reactor effluent was previously coagulated with 50 mgFeCl3.l-1 and flocculated under different conditions (mean velocity gradient, Gf, and flocculation time, Tf). The Gf values were from 60 to 100 s-1 associated with 13 and 20 min Tf values. During the tests, the following operational conditions of the flotation unit were maintained: chemical addition (50 mgFeCl3.l-1), 18% recirculation rate associated with a pressure of 450 ± 10 kPa in the saturation chamber and overflow rate of 180 m3.mÐ2.d-1. Temperature ranged from 23.8¡C to 30.01/4C. Best results were achieved for Gf = 80 s-1 and Tf = 20 min. For these conditions, the DAF unit removal efficiencies were: 94.4% for chemical oxygen demand (with 53 mg.l-1 COD residual), 87% for phosphorus (with 0.80 mgP.l-1 residual), 96.7% for total suspended solids (with 9 mg.l-1 TSS residual) and 96.4% for turbidity (with 12.9 NTU residual), when the anaerobic reactor effluents have worst quality during the whole day.


JUMINTEN ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 93-104
Author(s):  
Amanullah Fathurrahman ◽  
Iriani Iriani ◽  
Dwi Sukma Donoriyanto

CV. ABC merupakan pabrik yang bergerak dalam bidang olahan kayu seperti speaker aktif dan mebel-mebel. Dimana perusahaan tersebut memiliki sebuah komitmen internal dalam proses produksinya, agar dapat mengurangi dampak lingkungan dan memelihara ekosistem disekitarnya. Namun dalam kenyataannya, dalam proses produksinya baku mutu air perusahaan melebihi dari standar PERGUBJATIM No. 72 Tahun 2013, COD (Chemical Oxygen Demand) yang diatas batas standar sebesar 61,40 mg/l dan Oil and Grease sebesar 12 mg/l. Dimana akan berdampak pada lingkungan sekitar yang dapat mengganggu kesehatan lingkungan sekitar, selain itu dapat berdampak menurunnya produktivitas dan kinerja lingkungan perusahaan. Dengan adanya permasalahan tersebut pendekatan yang tepat untuk membantu perusahaan agar dapat mampu meningkatkan produktivitas serta kinerja lingkungan tersebut adalah dengan menerapkan metode Green Productivity (GP). Penelitian ini bertujuan untuk dapat mengevaluasi pengelolaan limbah berbasis Green Productivity, serta dapat memberikan usulan perbaikan dalam pengelolaan limbah. Hasil yang didapat diketahui bahwa terdapat 2 alternatif yang dapat menurunkan tingkat BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand), TSS (Total Suspeded Solid), Oil and Grease. Akan tetapi solusi yang dapat dijadikan usulan perbaikan adalah alternatif 2, yitu pemasangan alat DAF (Dissolved Air Flotation). Keuntungan yang didapatkan CV. ABC dengan alternatif 2 ini adalah peningkatan Green Productivity Index yang ditunjukan Green Productivity Ratio sebesar 13,06 dan Tingkat Produktivitas meningkat sebesar 0,01 %


Author(s):  
Siyasanga Mbulawa ◽  
Seteno Karabo Obed Ntwampe ◽  
Moses Basitere ◽  
Yolanda Mpentshu ◽  
Cynthia Dlangamandla ◽  
...  

Delipidation is a method of defatting that is generally associated with the removal of residual lipids or lipid groups from matrices in which they are present in minute quantities. The bio-delipidation of protein-rich poultry slaughterhouse wastewater (PSW) pre-treated with a dissolved air flotation (DAF) system was developed using microbial lipases from bacterial strains isolated from the PSW. The efficacy of the bio-delipidation system was quantitatively characterised by comparing the quality parameters i.e., fats, oil and grease (FOGs), turbidity, total suspended solutes (TSS), total chemical oxygen demand (tCOD) and protein concentration of the DAF pre-treated PSW and bio-lipidized samples. As hypothesised, the bio-delipidation system was able to effectively reduce the levels of these quality parameters when crude lipases of Bacillus cereus AB1 (BF3) and Bacillus cereus CC-1 (B30) strains were used. Strain-dependent quality characteristics were also observed in bio-delipidized samples. The study successfully managed to complement physical reduction techniques (DAF) with biological strategies (bio-delipidation) for improved PSW quality, with potential industrial applications.


1998 ◽  
Vol 38 (10) ◽  
pp. 99-105 ◽  
Author(s):  
S. Lainé ◽  
T. Poujol ◽  
S. Dufay ◽  
J. Baron ◽  
P. Robert

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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