Emulsified oily wastes

Emulsified oily wastes can present particular problems in handling, such as those originally intended to behave as emulsions (e.g. machine tool coolants), because of the stable nature of the emulsions involved. Two basic methods used on emulsified wastes are ... 

Pollutant parameters and their concentrations found in the oily waste subcategory streams are shown in Table 9.9. The oily waste subcategory for the metal finishing industry is characterized by both concentrated and dilute oily waste streams that consist of a mixture of free oils, emulsified oils, greases, and other assorted organics. Applicable treatment of oily waste streams is dependent on the concentration levels of the wastes, but oily wastes normally receive specific treatment for oil removal prior to solids removal waste treatment. 

Membranes are useful for stable emulsion removal particularly water-soluble oily wastes (8). This process is generally regarded as polishing technologies for emulsified oils. The low effluent concentrations of oil less than 5 mg/L could be achieved by this technique (2). Membrane processes have several advantages as described as follows (8,53) ... 

It was previously mentioned that PDADMAC (Cat-Floe) was the first commercial flocculant approved for potable water [26]. Since then, PDADMAC has been continuously used for coagulation/flocculation both in potable water and waste water treatment. A good example of the performance of PDADMAC in the coagulation of colloidal solids is the reduction of turbidity in fresh water of 150 mg L 1 of Ca(OH)2. A reduction of 82% in turbidity is observed with the addition of only 2 mg L 1 of branched PDADMAC [217]. In addition, PDADMAC and copolymers of DADMAC are reported to be effective in the removal of hard-to-elimi-nate impurities in the water treatment industry. Emulsified impurities from streams of a petroleum refinery waste water and an automotive oily effluent water have been removed by the use of water soluble copolymers consisting essentially of DADMAC and small amounts of anionic acrylic monomers [89]. 

Modern detergents effectively emulsify the oily and greasy soils removed from various materials. These emulsified oils and greases are major constituents of municipal and industrial wastes and therefore have great environmental significance. The TRITON RW-Series allow the separation of such oils from waste water and also permit recovery of the surfactant for reuse. 

Incineration is a possible (although never a popular) on-site treatment. The achievement of successful incineration may demand me use of special incinerating equipment wim gas or fuel oil present in me waste. Emulsified wastes, aimough containing a significant proportion of water, are often more readily incinerated man heavier oily wastewater. 

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