Removal of hydrocarbons from petrochemical wastewater by dissolved air flotation

2001 ◽  
Vol 43 (8) ◽  
pp. 107-113 ◽  
Author(s):  
N. I. Galil ◽  
D. Wolf
Keyword(s):  
Organic Matter ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Cationic Polyelectrolyte ◽  
Free Form ◽  
Dissolved Air Flotation ◽  
Separation Unit ◽  
Hydrophobic Compounds ◽  
Air Flotation ◽  
Dissolved Air

The dissolved air flotation (DAF) method has an important role in the removal of hydrocarbons, as well as in the protection of the biological treatment, which usually follows the DAF. The aims of this study were to evaluate the removal efficiencies of suspended solids, general organic matter, hydrocarbons and phenols by DAF, as influenced by the flocculant type, aluminum sulfate (alum) or a cationic polyelectrolyte. Laboratory batch experiments included chemical flocculation followed by DAF, controlling the flocculant dose and the air to solids ratio. The characterization of the influent and effluent was based on general analysis of organic matter (COD), suspended solids, hydrocarbons and phenols. The influent to all experiments was supplied daily from the outlet of a full scale oil-water gravitational separation unit at a petrochemical complex in Haifa, Israel. The influent contained hydrocarbons in the range of 20 to 77 mg/L. Usually less than 10% were found in “free” form, 70 to 80% were emulsified and 10 to 20% were dissolved. The DAF process enabled us to reduce the general hydrocarbon content by 50 to 90%. The effluent was characterized by stable and uniform levels of suspended solids, and oil, almost without depending on the influent concentrations. The results indicate that the chemical flocculation followed by DAF removed efficiently the emulsified phase, which could be aggregated and separated to the surface. However, it was found that the process could also remove substantial amounts of dissolved organic matter. This mechanism could be explained by the hydrophobic characteristics of some of the substances, which could bind to the solid surfaces. It was found that aggregates created by the flocculation with the cationic polyelectrolite (C-577) could remove up to 40% from the dissolved hydrocarbon. Alum flocs also indicated removal of soluble materials, mainly phenols. The results obtained in this study indicated the possibility to improve the protection of the biological treatment process by preliminary removal of hydrophobic compounds, usually considered as either inhibitory or toxic. This removal can be based on sorption onto aggregates created by chemical flocculation, which can be efficiently removed by dissolved air flotation.

Emerging investigator series: control of membrane fouling by dissolved algal organic matter using pre-oxidation with coagulation as seawater pretreatment

2020 ◽  
Vol 6 (4) ◽  
pp. 935-944 ◽  
Author(s):  
Bhaskar Jyoti Deka ◽  
Jiaxin Guo ◽  
Sanghyun Jeong ◽  
Manish Kumar ◽  
Alicia Kyoungjin An
Keyword(s):  
Organic Matter ◽  
Membrane Fouling ◽  
Chemical Oxidation ◽  
Dissolved Air Flotation ◽  
Algal Organic Matter ◽  
Wet Chemical ◽  
Air Flotation ◽  
Dissolved Air

High AOM removal achieved by pre-oxidation with coagulation–flocculation-dissolved air flotation. In situ ferrate was formed by wet chemical oxidation of NaOCl-Fe3+. Membrane fouling was significantly alleviated and assessed by OCT technique.

Oil Removal from Refinery Wastes by Air Flotation

1974 ◽  
Vol 9 (1) ◽  
pp. 328-339 ◽  
Author(s):  
B. Volesky ◽  
S. Agathos
Keyword(s):  
Suspended Solids ◽  
Suspended Solid ◽  
Oil Removal ◽  
Dissolved Air Flotation ◽  
Physical Separation ◽  
Sedimentation Technique ◽  
Flocculation Aid ◽  
Flotation Technique ◽  
Air Flotation ◽  
Dissolved Air

Abstract Air flotation as a physical separation process for removing oily products and suspended solid matter from refinery wastewaters achieves removal efficiencies from 65% to more than 90%. Demonstrated capacity of the process for COD and BOD removal ranges up to 90%. With addition of flotation and flocculation aid chemicals better performance is achieved. Current results are presented and critically reviewed. It appears that the pressure dissolved-air flotation system employing recycle-flow operation can produce effluent containing consistently less than 15 p.p.m. of oil and suspended solids. Its performance and capacity of handling overload situations makes it superior to the conventional flocculation-sedimentation technique. Oil removal limitations of the process and current research trends are stressed including an electro-flotation technique. Some aspects of process optimization are also discussed.

A bioflocculant-supported dissolved air flotation system for the removal of suspended solids, lipids and protein matter from poultry slaughterhouse wastewater

2018 ◽  
Vol 78 (2) ◽  
pp. 452-458 ◽  
Author(s):  
C. Dlangamandla ◽  
S. K. O. Ntwampe ◽  
M. Basitere
Keyword(s):  
Steady State ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Bacillus Sp ◽  
Dissolved Air Flotation ◽  
Slaughterhouse Wastewater ◽  
Air Flotation ◽  
Dissolved Air

Abstract In this study, two previously identified isolates, i.e. Comamonas aquatica (BF-3) and Bacillus sp. BF-2, were determined to be suitable candidates to utilise in a bioflocculant-supported dissolved air flotation (Bio-DAF) system as a pretreatment system for poultry slaughterhouse wastewater (PSW). A 2% (v/v) (bioflocculant:PSW) strategy was used for the DAF to reduce total suspended solids (TSS), lipids and proteins in the PSW, by supplementing the bioflocculants produced and the co-culture (C. aquatica BF-3 and Bacillus sp. BF-2) directly into the DAF. The Bio-DAF was able to reduce 91% TSS, 79% proteins and 93% lipids when the DAF system was operating at steady state, in comparison with a chemical DAF operated using 2% (v/v) alum that was able to only reduce 84% TSS, 71% proteins and 92% lipids. It was concluded that the Bio-DAF system worked efficiently for the removal of suspended solids, lipids and proteins, achieving better results than when alum was used.

First full-scale combined MBBR, coagulation, flocculation, Discfilter plant with phosphorus removal in France

2019 ◽  
Vol 15 (1) ◽  
pp. 19-27 ◽  
Author(s):  
P. Kängsepp ◽  
M. Sjölin ◽  
A. G. Mutlu ◽  
B. Teil ◽  
C. Pellicer-Nàcher
Keyword(s):  
Total Phosphorus ◽  
Phosphorus Removal ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Full Scale ◽  
Small Scale ◽  
Dissolved Air Flotation ◽  
Biofilm Reactors ◽  
Dissolved Air

Abstract The suspended solids (SS) concentrations in effluent from moving bed biofilm reactors (MBBRs) used for secondary biological treatment can be up to 500 mg/L. Microscreens (Drumfilters or Discfilters) can be used as alternatives to traditional clarification or dissolved air flotation to remove SS and total phosphorus (TP). This study shows how a small-scale municipal WWTP for 5,700 population equivalent (PE) can be upgraded to 12,000 PE by combining MBBR with coagulation-flocculation tanks and a Discfilter with a total footprint of 160 m2. This long-term investigation demonstrated that even though influent turbidity (range 146–431 NTU) and flow (25–125 m3/h) varied considerably, very low effluent turbidities (below 10 NTU) could be achieved continuously. Furthermore, this compact treatment system can provide average reductions of ammonium (NH4-N) from 19 to 0.04 mg/L, COD from 290 to 10 mg/L, and TP from 4.5 to 0.3 mg/L. The results show that effluent requirements can be reached by combining MBBR, coagulation-flocculation and disc filtration at full scale, without a primary clarifier upstream of MBBR.

Disturbances and Inhibition in Biological Treatment of Wastewater from an Integrated Refinery

1988 ◽  
Vol 20 (10) ◽  
pp. 21-29 ◽  
Author(s):  
N. Galil ◽  
M. Rebhun ◽  
Y. Brayer
Keyword(s):  
Pilot Plant ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Biological Process ◽  
Oil Refinery ◽  
Process Rate ◽  
Inhibitory Effects ◽  
Dissolved Air Flotation ◽  
Mixed Liquor ◽  
Dissolved Air

Biological treatment of wastewater from an integrated oil refinery, containing hazardous contaminants, was studied in an on site pilot plant. The wastewater is pretreated by gravity separation, flocculation and dissolved air flotation. Biotreatment of such wastewaters poses several problems which have to be considered in planning, design and operation of the treatment system. The process rate is relatively slow, due to the inhibitory effects. The mixed liquor volatile suspended solids (MLVSS) could not be maintained at concentrations higher than 2000 mg/l. Sudden discharges of concentrated phenolic wastes disrupted the process first by impairing bioflocculation, followed by complete inhibition of the biological process.

Enhancing organic matter removal in desalination pretreatment systems by application of dissolved air flotation

Desalination ◽  
2016 ◽  
Vol 383 ◽  
pp. 12-21 ◽  
Author(s):  
Yulia Shutova ◽  
Barun Lal Karna ◽  
Adam C. Hambly ◽  
Belinda Lau ◽  
Rita K. Henderson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Air Flotation ◽  
Organic Matter Removal ◽  
Air Flotation ◽  
Dissolved Air

Plywood Mill Water System Closure by Dissolved Air Flotation Treatment

1999 ◽  
Vol 40 (11-12) ◽  
pp. 33-41 ◽  
Author(s):  
P. Jokela ◽  
P. Keskitalo
Keyword(s):  
Heat Recovery ◽  
Occupational Safety ◽  
Suspended Solids ◽  
Water System ◽  
Raw Material ◽  
Surface Load ◽  
Dissolved Air Flotation ◽  
Treated Water ◽  
Air Flotation ◽  
Dissolved Air

In plywood industry water is mainly needed for soaking the logs. Dissolved air flotation with chemical precipitation was found to be a suitable treatment method for the soaking basin overflow of a plywood mill using birch as raw material. According to pilot treatment studies over 90% reductions of the suspended solids are possible with a hydraulic surface load of 6.5 m3/(m2h). In subsequent experience in full scale following reductions have been achieved: suspended solids 93%, BOD7 50%, CODCr 57%, P 92% and N 52%. Two-thirds of the flotation treated water is led to flue gas scrubbers and circulated back to the soaking basin. Optionally water can be led to the heat recovery, too. One-third of the flotation treated water is disposed of as the mill effluent. Concentrations of organic matter in the system have been reduced after the addition of flotation indicating the possibility of further closure. However, due to the use of aluminium sulphate in coagulation, aeration is needed for sulphate reduction prevention. Further closure of the water system is possible in the future if the heat recovery is renovated, preventing the increase of the water temperature (now 37°C) which otherwise might cause occupational safety hazards.

Dissolved air flotation clarification of activated sludge and wastewaters from chemical industry

2003 ◽  
Vol 47 (1) ◽  
pp. 205-210 ◽  
Author(s):  
P. Jokela ◽  
J. Immonen
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Animal Feed ◽  
Paper Industry ◽  
Dissolved Air Flotation ◽  
Jar Test ◽  
Air Flotation ◽  
Carry Over ◽  
Winter Time ◽  
Dissolved Air

Wastewaters from separate chemical factories are treated together in an extended aeration activated sludge plant. The factories produce chemicals for paper industry (e.g. starch), latexes and animal feed. The components of the wastewaters include styrene, tertiary butanol and vinyl acetate. Activated sludge is clarified by sedimentation. During winter time, when the water temperature was 3-12°C, the clarification deteriorated causing carry over of suspended solids containing COD. Enhancement of suspended solids and COD removals was studied in a dissolved air flotation jar test unit. Flotation trials were conducted for activated sludge, sedimentation treated final effluent (tertiary treatment) and separate wastewater fractions. The need for chemicals, flocculation and amount of recycle water were judged according to the achieved removals. Dissolved air flotation was found well suited for the clarification of activated sludge, but not technically and economically feasible for the clarification of the wastewater streams before the activated sludge treatment.

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