Physical-Chemical Methods of Treatment for Oil-Containing Effluents

1982 ◽  
Vol 14 (9-11) ◽  
pp. 1195-1207 ◽  
Author(s):  
F Berné
Keyword(s):  
Biological Treatment ◽  
Oil Removal ◽  
Chemical Methods ◽  
Treatment Unit ◽  
Dissolved Air Flotation ◽  
Hydrocarbon Content ◽  
Physical Chemical ◽  
Pipe Line ◽  
Methods Of Treatment ◽  
Dissolved Air

After a preliminary oil-removal by gravity in various types of oil-separators, the effluents from pipe-line terminals, de-ballasting units and refineries still contain, as a stable emulsion, significant residual hydrocarbon concentrations, varying from 25 to 300 mgl. In order to bring these effluents to comply with the regulations governing their discharge either to the sea or to a river, or simply to be able to send them to a complementary biological treatment unit, it is necessary to submit such effluents to a polishing oil-removal process; such process, often called physical-chemical treatment, is necessary to remove the above mentioned residual, insoluble hydrocarbons and leave the soluble hydrocarbons only. Practically and depending on the case considered, the final total hydrocarbon content obtained should not exceed from 5 to 20 mgl−1. For this, there are several techniques based on dissolved air flotation, or filtration. These respective processes and their results are summarized hereafter by the authors who gathered them from experiments conducted on pilot plants and, most of all, from numerous industrial treatment plants in Europe and in America.

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.

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.

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.

An Investigation into the Pre-Treatment of Dairy Wastewater Prior to Aerobic Biological Treatment

1994 ◽  
Vol 29 (9) ◽  
pp. 205-212 ◽  
Author(s):  
B. Kasapgil ◽  
G. K. Anderson ◽  
O. Ince
Keyword(s):  
Biological Treatment ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Dairy Wastewater ◽  
Dissolved Air Flotation ◽  
The United Kingdom ◽  
Pre Treatment ◽  
Urban Wastewater Treatment ◽  
Final Effluent ◽  
Dissolved Air

Implementation of the EC Directive on Urban Wastewater Treatment has led to the introduction of more stringent discharge standards being imposed by the Regulating Agencies in the United Kingdom. It is for this reason that this investigation into the pre-treatment of a dairy wastewater prior to aerobic biological treatment was carried out. In order to upgrade the existing treatment plant at a local dairy a Dissolved Air Flotation (DAF) and an anaerobic digestion system as pre-treatment process were studied at pilot - scale. Results obtained from this study showed that the existing aerobic biological treatment plant failed to achieve both the present consent conditions and those required in 1995. It was shown that an anaerobic filter would enable the plant to meet the discharge standards proposed by the National Rivers Authority but due to the configuration of the land available for new works it is recommended that the existing aerobic biological filter be replaced by an activated sludge system. It is anticipated that such a system would reduce the final effluent COD to less than 125 mg/l.

Oil removal efficiency forecast of a Dissolved Air Flotation (DAF) reduced scale prototype using the dimensionless number of Damköhler

2018 ◽  
Vol 23 ◽  
pp. 45-49 ◽  
Author(s):  
Fernanda Cristina P. Rocha e Silva ◽  
Nathalia Maria P. Rocha e Silva ◽  
Ivison Amaro da Silva ◽  
Pedro P. Ferreira Brasileiro ◽  
Juliana M. Luna ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Dimensionless Number ◽  
Oil Removal ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Reduced Scale ◽  
Dissolved Air

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

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.

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