Post-treatment of effluents from anaerobic reactor treating domestic sewage by dissolved-air flotation

1999 ◽  
Vol 40 (8) ◽  
Keyword(s):  
Domestic Sewage ◽  
Post Treatment ◽  
Dissolved Air Flotation ◽  
Anaerobic Reactor ◽  
Air Flotation ◽  
Dissolved Air

Influence of flocculation conditions in the performance of an experimental domestic sewage treatment plant consisting of an anaerobic expanded bed reactor followed by dissolved air flotation

2003 ◽  
Vol 48 (6) ◽  
pp. 285-293
Author(s):  
R.G. Penetra ◽  
M.A.P. Reali ◽  
J.R. Campos
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Domestic Sewage ◽  
Expanded Bed ◽  
Mean Velocity ◽  
Dissolved Air Flotation ◽  
Anaerobic Reactor ◽  
Air Flotation ◽  
Dissolved Air

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.

Evaluation of flocculation and dissolved air flotation as an advanced wastewater treatment

2001 ◽  
Vol 43 (8) ◽  
pp. 83-90 ◽  
Author(s):  
A. C. Pinto Filho ◽  
C. C. Brandão
Keyword(s):  
Wastewater Treatment ◽  
Domestic Wastewater ◽  
High Rate ◽  
Advanced Treatment ◽  
Dissolved Air Flotation ◽  
Anaerobic Reactor ◽  
Treatment Processes ◽  
Domestic Wastewater Treatment ◽  
Air Flotation ◽  
Dissolved Air

A bench scale study was carried out in order to evaluate the applicability of dissolved air flotation (DAF) as an advanced treatment for effluents from three different domestic wastewater treatment processes, namely: (i) a tertiary activated sludge plant ; (ii) an upflow sludge blanket anaerobic reactor (UASB); and (iii) a high-rate stabilization pond.

Post-Treatment of Effluents from Anaerobic Reactor Treating Domestic Sewage by Dissolved-Air Flotation

1999 ◽  
Vol 40 (8) ◽  
pp. 137-143 ◽  
Author(s):  
R. G. Penetra ◽  
M. A. P. Reali ◽  
E. Foresti ◽  
J. R. Campos
Keyword(s):  
Scale Up ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Dissolved Air Flotation ◽  
Operational Conditions ◽  
Apparent Color ◽  
Air Flotation ◽  
Dissolved Air

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.

Ozonation followed by coagulation/flocculation and flotation as post-treatment of the effluent from an anaerobic baffled reactor treating domestic sewage

2001 ◽  
Vol 43 (8) ◽  
pp. 99-106 ◽  
Author(s):  
M. M. Marchioretto ◽  
M. A. Reali
Keyword(s):  
Ph Value ◽  
Domestic Sewage ◽  
Post Treatment ◽  
Dissolved Air Flotation ◽  
Anaerobic Baffled Reactor ◽  
Ozone Dose ◽  
Apparent Color ◽  
Consequent Reduction ◽  
High Degree ◽  
Dissolved Air

This paper reports on the use of ozonation and dissolved air flotation as a post-treatment of the effluent from an anaerobic baffled reactor treating domestic sewage. After preliminary essays, the present experiment was performed fixing coagulant doses and, to all of them, some ozone doses were investigated. Later, the pH value and the ozone dose which provided the best removal efficiencies of all the parameters involved were tested, changing the coagulant dose and varying, for each of them, two ozone doses: the zero one and the optimum. Considering the best conditions of coagulation/flotation (ferric chloride dose of 65 mg.L−1: and pH around 5.5), the ozone dose application of 6 mg.L−1 led to a significant level in the removal efficiency of COD (80.4%), BOD (79.0%), total phosphate (93.4%), apparent color (91.9%) and turbidity (97.0%), demonstrating that the system seems to be efficient and capable of promoting a high degree of sewage post-treatment, reducing the coagulant dose until 30%, with a consequent reduction in the sludge generation.

scholarly journals Evaluating Pre- and Post-Coagulation Configuration of Dissolved Air Flotation Using Response Surface Methodology

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 383 ◽  
Author(s):  
Emmanuel Kweinor Tetteh ◽  
Sudesh Rathilal
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Cost Effective ◽  
Post Treatment ◽  
Oil Refinery ◽  
Optimum Conditions ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Pre Treatment ◽  
Dissolved Air

The effects of coagulation-dissolved air flotation (DAF) process configuration was studied on oil refinery wastewater. The configuration was done in two ways: acid-coagulation-DAF (pre-treatment) and acid-DAF-coagulation (post-treatment). Two different cationic and polymeric organic coagulants were employed in this study to compare their treatability performance with the two aforementioned configurations. All the coagulants applied before the DAF were found to be effective, with over 85% more contaminant removal efficiency than their post-treatment. Alum, being the most cost-effective coagulant, was then employed with response surface methodology (RSM) to obtain the optimum conditions. These include a coagulant dosage of 100 mg/L, air saturator pressure of 375 kPa and air–water ratio of 10% vol/vol corresponding to a desirability of 92% for the removal of oily pollutants from a local South Africa oil refinery’s wastewater. With the response quadratic models that were developed, the optimum conditions were tested experimentally, which were consistent with the models predicted results at a 95% confidence level.

Behaviour of air injection nozzles in dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 25-35 ◽  
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.

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.

Fat recovery from dissolved air flotation sludge

2016 ◽  
Vol 2016 (9) ◽  
pp. 3543-3551
Author(s):  
H.W.H Menkveld ◽  
N. C Boelee ◽  
G.O.J Smith ◽  
S Christian
Keyword(s):  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air
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