Mechanical methods, destructive nature

The physical and chemical removal of oil spills can often be successful, but mostly expensive. We can mention soil incineration, soil vapor extraction and thermal desorption methods, all of which are very expensive and destructive (Hyman, 1999). Besides that the primary goal of remediation is the preservation of public health and safety, it is necessary to carry out the remediation in a cost-effective manner to keep the owner/operator of the site in business and out of bankruptcy court. In this case, biodegradation by natural population of microorganisms or bioremediation, is often considered as the primary mechanism because of its low cost and effectiveness in ambient conditions. The scientific basis is biochemical conversion of organic chemicals by bacteria and fungus in natural processes. 

There are many industrial processes in which the formation of low internal phase or concentrated emulsions needs to be controlled in terms of formation, stability, destruction or prevention. Examples range from asphalt emulsions to personal care products, and to food products. Success in emulsion control requires achieving the right physical chemistry and also the right fluid mechanics. In addition to HLB (see Section 7.2.1), both the nature of the emulsification method and the oil-water ratio are critical in determining the produced emulsion type. It appears that the emulsification technique (applied shear and oil-water ratio) used can be of greater importance in determining the final emulsion type than the HLB values of the surfactants themselves. 

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