Polymer sludge

A = Maximum filtrate volume obtainable B = A at t = 0 for a perfect fit of the equation r = Dewatering rate parameter—dependent upon the polymer sludge floe characteristics (as well as ionic strength, pH media viscosity, and temperature, all of which would remain constant for a given sludge blend during a specific evaluation period). It is defined as 0 < r < L-t — Time expressed in seconds... 

Phosphate—Polymer Control. Phosphate treatment results are improved by organic supplements. Naturally occurring organics such as lignins, tannins, and starches were the first supplements used. The organics were added to promote the formation of a fluid sludge that would settle in the mud dmm. Bottom blowdown from the mud dmm removed the sludge. 

Fat. The sludge was steam-heated in the press and treated with CaO and polymer. About 95% of the sohds were retained in the cake (38). ... 

As with thickening, air flotation is enhanced by the addition of polymers. Flotation has been successfully used with wholly inorganic metal hydroxide sludges. Polymers and surfactants are used as additives. Engineering details on air flotation equipment has been developed by and is available from various equipment manufacturing companies. Liquid removed during thickening and flotation is usually returned to the head end of the plant. 

Major categories of industrial waste solidiflcation/stabilization systems are cement-based processes, pozzolanic processes (not including cement), thermoplastic techniques, organic polymer techniques, surface encapsulation techniques, and self-cementing techniques (for high calcium sulfate sludges). Vitrification (discussed previously) can also be considered a solidification process. 

Membrane processes also offer other advantages over conventional treatments. They reduce the number of unit processes in treatment systems for clarification and disinfection and increase the potential for process automation and plant compactness. Designers also thought membrane plants could be much smaller than conventional plants of the same capacity and, given their modular configuration, could be easily expanded. Additionally, these plants would produce less sludge than conventional plants because they wouldn t use such chemicals as coagulants or polymers. 

Hydrofining has all the advantages of acid treating without the disadvantages. For example, acid treating does not readily remove refractory sulfur compounds such as thiophene the treated products must be rerun to remove polymers with a consequent yield loss and disposal of the acid sludges is a serious problem. 

Where a softener has not been provided, a higher volume of sludge can be expected in the BW. Typically, the calcium precipitates either as insoluble carbonate scale or as phosphate sludge except where a chelant-based chemical treatment program is employed (which is unlikely in smaller boiler plants) or when an all-polymer program is employed. 

Even where these organic polymer materials are employed, their ability to disperse sludge and transport hardness salts may be constrained by limited BD and other factors. Some sludge still develops. The fact remains that boilers simply are not designed to be settling and clarifying vessels. 

NOTE All-polymer programs employ various types of organic deposit control agents (DCA) such as phosphinocarboxylic acid (PCA) products, which tend to be high temperature-stable sludge dispersants, crystal modifiers, and hardness transporters. 

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