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.

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.

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.

Flow structures in a dissolved air flotation pilot tank and the influence on the separation of MBBR floc

2002 ◽  
Vol 2 (2) ◽  
pp. 69-76 ◽  
Author(s):  
M. Lundh ◽  
L. Jönsson ◽  
J. Dahlquist
Keyword(s):  
Flow Structure ◽  
Removal Efficiency ◽  
Pilot Plant ◽  
Suspended Solids ◽  
Short Circuit ◽  
Flow Structures ◽  
Dissolved Air Flotation ◽  
Air Content ◽  
Air Flotation ◽  
Dissolved Air

The objective of the study was to find ways of improvement of the dissolved air flotation process by studying the flow structure. The paper presents experimental data on flow structures and the relation between the flow structure and the removal efficiency. Measurements have been performed in a pilot plant with an Acoustical Doppler Velocimeter. The water velocity was measured in a grid net, giving insight into the flow structure. The removal efficiency was analysed at Malmö wastewater treatment plant in Sweden. The pilot plant separated biological floc from a Kaldnes Moving Bio-Bed Reactor (MBBR). The efficiency of the separation was analysed by measurements of suspended solids in the influent and the effluent. Air content was measured inside the tank and in the re-cycle. The result showed that basically two flow structures existed; the stratified and the short-circuit flow structure. The stratified flow structure seemed correlated to efficient separation of particles while the short-circuit flow structure seemed to have a negative effect, especially when the flow structure was affected by varying the re-cycle rate, i.e. the air content. Conclusively, the flow structure seemed to be correlated to type of flow structure. However, studies with higher concentration of suspended solids for verification were suggested.

Optimising dissolved air flotation/filtration treatment of algae-laden lagoon effluent using surface charge: a Bolivar treatment plant case study

2012 ◽  
Vol 66 (8) ◽  
pp. 1684-1690 ◽  
Author(s):  
Russell Yap ◽  
Michael Holmes ◽  
William Peirson ◽  
Michael Whittaker ◽  
Richard Stuetz ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Surface Charge ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
A Charge ◽  
Dissolved Air

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.

An Investigation of the Treatment and Recycling of Oil Refinery Wastewater

1986 ◽  
Vol 18 (9) ◽  
pp. 105-114 ◽  
Author(s):  
D. Misković ◽  
B. Dalmacija ◽  
Ž Živanov ◽  
E. Karlović ◽  
Z. Hain ◽  
...  
Keyword(s):  
Oil Refinery ◽  
Refinery Wastewater ◽  
Dissolved Air Flotation ◽  
Microbiological Oxidation ◽  
Dissolved Matter ◽  
High Level ◽  
High Degree ◽  
Improved Methods ◽  
Oil Refinery Wastewater ◽  
Dissolved Air

The objective of the present investigation was a high level of purification of the wastewater from an oil refinery achieved by using some improved methods yielding an effluent suitable for recycling into the process. All the investigations were carried out on a continuous laboratory pilot system consisting of the following units: dissolved air flotation (DAF), sedimentation, double-stage microbiological reactor, and adsorption columns filled with granular biologically activated carbon (GBAC). A high degree of COD reduction close to 100% (precisely, 99.95 %), as well as removal of nitrogen compounds of 72% was achieved during a relatively short retention time within the range of 15-16.5 hrs. The DAF technique combined with gravitational separation was used to achieve the recovery of free oil matter up to 98%, without any preliminary conditioning. After the sedimentation of coagulated and flocculated dispersed oils, the microbiological oxidation of dissolved matter was accomplished by using two kinds of activated sludge for easy and hard degradable organics. Using the continuously bioregenerating GBAC, an effluent having a lowered COD value to about 9 was obtained. At the same time, the denitrification process took place. According to the obtained results the treated oil refinery wastewater can be recycled into the process, or discharged into a water recipient of a low self-purifying capacity.

Nocardia effects in waste activated sludge

1998 ◽  
Vol 38 (2) ◽  
pp. 49-54 ◽  
Author(s):  
Krishna R. Pagilla ◽  
David Jenkins ◽  
Wendell Kido
Keyword(s):  
Activated Sludge ◽  
Foam Stability ◽  
Anaerobic Digester ◽  
Waste Activated Sludge ◽  
Dissolved Air Flotation ◽  
Anaerobic Digesters ◽  
Primary Sludge ◽  
Mixed Liquor ◽  
Dissolved Air ◽  
Batch Foaming

Two effects of Nocardia in waste activated sludge (WAS) were investigated: (i) the influence of WAS in the solids treatment recycle streams on Nocardia persistence in the activated sludge, and (ii) the effect of Nocardia in WAS on anaerobic digester foaming. About 4% of the Nocardia present in the mixed liquor was due to seeding from the WAS solids in the dissolved air flotation thickener recycle stream recycle. Nocardia filaments in WAS at levels of between 104 to 106 intersections/g VSS resulted in Nocardia levels of approximately 104 to 105 intersections/g VSS in anaerobic digesters that treated both WAS and primary sludge. The effect of disinfecting these Nocardia filaments in the WAS with Cl2 was investigated at Cl2 dose ranges of 20-60 mg Cl2/l WAS and 100-200 mg Cl2/l WAS on a lab scale using batch foaming tests to assess success. Chlorination with 20 - 60 mg Cl2/l WAS approximately doubled both sludge foaming potential and foam stability. At Cl2 doses of 100-200 mg Cl2/l WAS, foaming potential was increased almost 10-fold, and foam stability was increased by 2.5 times. These results indicate that chlorination of WAS feed to an anaerobic digester for inactivation of Nocardia should not be practiced.

scholarly journals Automation and Control of a Dissolved Air Flotation Pilot Plant

2017 ◽  
Vol 50 (1) ◽  
pp. 3911-3916 ◽  
Author(s):  
Rodolpho R. Fonseca ◽  
José P. Thompson, Jr. ◽  
Ivan C. Franco ◽  
Flávio V. da Silva
Keyword(s):  
Pilot Plant ◽  
Dissolved Air Flotation ◽  
Automation And Control ◽  
Air Flotation ◽  
And Control ◽  
Dissolved Air

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.

Enhancement of microbubble generation in a pressurized dissolution process by packing the nozzle with porous ceramics

2012 ◽  
Vol 65 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Hiroshi Yamashita ◽  
Hideki Aoyagi ◽  
Hisato Minagawa
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Porous Ceramic ◽  
Operating Cost ◽  
Porous Ceramics ◽  
Packing Material ◽  
Dissolved Air Flotation ◽  
Dissolution Method ◽  
Main Disadvantage ◽  
Dissolved Air

The pressurized dissolution method is often used for microbubble generation. However, the main disadvantage of this method is that a large amount of energy (more than 0.3 MPa) is required to generate many microbubbles, each of which have a diameter of several dozen μm. To overcome this problem, we investigated the effectiveness of porous ceramic when used as the packing material in the pressurized dissolution method. The results showed that when compared with the control (no porous ceramics), use of porous ceramics resulted in a 39% increase in the number of microbubbles. Furthermore, when this system was used for the flotation separation of artificial suspended solids and activated sludge, the level of separation achieved with porous ceramics at 0.15 MPa was the same as that achieved using no porous ceramics at 0.25 MPa. It was estimated that the use of porous ceramics led to a 40% reduction in the energy required for the dissolved air flotation, with subsequent decreases in the operating cost.

Sign in / Sign up

Export Citation Format

Share Document