Induced gas flotation
Encyclopedia
Induced Gas Flotation is a water treatment
process that clarifies wastewater
s (or other waters) by the removal of suspended matter such as oil or solids. The removal is achieved by injecting air bubbles into the water or wastewater in a flotation tank or basin. The small bubbles adhere to the suspended matter causing the suspended matter to float to the surface of the water where it may then be removed by a skimming device.
Induced Gas Flotation is very widely used in treating the industrial wastewater effluent
s from oil refineries
, petrochemical
and chemical plant
s, natural gas processing plants
and similar industrial facilities. A very similar process known as dissolved air flotation is also used for waste water treatment. Froth flotation
is commonly used in the processing of mineral ores.
IGF Units in the oil industry do not use air as the flotation medium due to the explosion risk. These IGF Units use natural gas
to create the bubbles.
(such as ferric chloride or aluminum sulfate) to flocculate the suspended matter.
The bubbles may be generated by an impeller, eductors or a sparger. The bubbles adhere to the suspended matter, causing the suspended mater to float to the surface and form a froth layer which is then removed by a skimmer. The froth-free water exits the float tank as the clarified effluent from the IGF unit.
Some IGF unit designs utilize parallel plate packing material to provide more separation surface and therefore to enhance the separation efficiency of the unit.
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
process that clarifies wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
s (or other waters) by the removal of suspended matter such as oil or solids. The removal is achieved by injecting air bubbles into the water or wastewater in a flotation tank or basin. The small bubbles adhere to the suspended matter causing the suspended matter to float to the surface of the water where it may then be removed by a skimming device.
Induced Gas Flotation is very widely used in treating the industrial wastewater effluent
Effluent
Effluent is an outflowing of water or gas from a natural body of water, or from a human-made structure.Effluent is defined by the United States Environmental Protection Agency as “wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers...
s from oil refineries
Oil refinery
An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...
, petrochemical
Petrochemical
Petrochemicals are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as corn or sugar cane....
and chemical plant
Chemical plant
A chemical plant is an industrial process plant that manufactures chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transformation and or separation of materials. Chemical plants use special equipment,...
s, natural gas processing plants
Natural gas processing
Natural-gas processing is a complex industrial process designed to clean raw natural gas by separating impurities and various non-methane hydrocarbons and fluids to produce what is known as pipeline quality dry natural gas.-Background:...
and similar industrial facilities. A very similar process known as dissolved air flotation is also used for waste water treatment. Froth flotation
Froth flotation
Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in several processing industries...
is commonly used in the processing of mineral ores.
IGF Units in the oil industry do not use air as the flotation medium due to the explosion risk. These IGF Units use natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
to create the bubbles.
Process description
The feed water is to the IGF float tank is often (but not always) dosed with a coagulantCoagulant
Coagulant can refer to:* flocculation* coagulation agent...
(such as ferric chloride or aluminum sulfate) to flocculate the suspended matter.
The bubbles may be generated by an impeller, eductors or a sparger. The bubbles adhere to the suspended matter, causing the suspended mater to float to the surface and form a froth layer which is then removed by a skimmer. The froth-free water exits the float tank as the clarified effluent from the IGF unit.
Some IGF unit designs utilize parallel plate packing material to provide more separation surface and therefore to enhance the separation efficiency of the unit.
See also
- Industrial water treatmentIndustrial water treatmentIndustrial Water Treatment can be classified into the following categories:* Boiler water treatment* Cooling water treatment* Wastewater treatment...
- WastewaterWastewaterWastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
- Industrial wastewater treatmentIndustrial wastewater treatmentIndustrial wastewater treatment covers the mechanisms and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use....
- Flotation processFlotation processFlotation process is a method of separation widely used in the wastewater treatment and mineral processing industries.Various flotation processes include the following:* Dissolved air flotation...
- Dissolved air flotation
- API oil-water separatorAPI oil-water separatorAn API oil-water separator is a device designed to separate gross amounts of oil and suspended solids from the wastewater effluents of oil refineries, petrochemical plants, chemical plants, natural gas processing plants and other industrial sources...