Oily wastewater gravity

This system normally uses a condenser discharge directly to a hot well and then to a cooling tower, often by gravity. The cooling tower overflow and blow down is discharged to a wastewater treatment facility as part of the plant oily wastewater handling needs. 

In oily wastewater treatment, two types of oil are need to be removed free and emulsified oils. Free oil has lower specific gravity than water. It can rapidly rise to the surface, thus it is called floatable oil. It is generally considered to have droplet sizes larger than 250 [tm in diameter. 

Oily wastewater treatment can be classified into two categories primary and secondary treatment systems. The primary treatment is employed to separate floatable oils from water and emulsified oil. This system is suitable for oil or grease that is of lower specific gravity than water. Skimmer and gravity separation are the major treatment systems belonging to this group. A secondary treatment system s goal is to treat or... 

Flotation system this process is functioned by increased differences in specific gravity between the oil and water by blowing fine air bubbles through the oily wastewater. The most common floatation system is dissolved air flotation (DAE) process. 

Dissolved air flotation (DAF) is a process commonly used in refineries to enhance oil and suspended solids from gravity-separator effluent. In some refineries it is used as a secondary clarifier for activated sludge systems and as a sludge thickener. The process involves pressurizing the influent or recycled wastewater at 3-5 atm (40-70 psig) then releasing the pressure, which creates minute bubbles that float the suspended and oily particulates to the surface. The float solids are removed by a mechanical surface collector. 

Induced Gas Flotation. Mechanically induced gas dotation (IGF) is employed extensively to remove suspended solids, oil, and other organic matter from oil-field and refinery wastewaters. Consequently, these IGF units are particularly suited to the treatment of oil-in-water or reverse emulsions. Such units generally follow gravity oil-water separation units such as FWKOs, gun barrels, and skim tanks in oil-field-produced water-treatment schemes, and also handle the oily water streams generated from all treaters in a specific produced-fiuid treatment plant. 

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