Remove Sludge and Soils Promptly

6 Remove Sludge and Soils Promptly. Removing sludge and soils from aqueous cleaning soak tanks will reduce chemical use by increasing the permissible time interval between dumping and total cleanout of the tank. 

Alkaline cleaners are available which allow the separation of excess oily soil from the cleaner. These formulations involve the use of surfactants that are good detergents but poor emulsifiers. Agitation of the bath during the work shift causes a temporary emulsification, which keeps the soil in suspension. After a prolonged period of inactivity (usually overnight), the oily soils float to the surface where they are skimmed off. This method is quite effective with mineral oil-type soils but is less so with fatty oils. 

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