Removal of Precipitated Heavy Metals, Solids and Oils

Characteristics of three different petrochemical wastewaters and their components 

Note VCM = vinyl chloride monomer EDC = 12 dichloroethane [Lahiere and Goodboy, 1993] 

Removal of EDC emulsions. A commonly occurring alkaline (pH of 12-13) process waste stream in VCM plants contains emulsions of EDC, water and inorganic solids such as calcium/iron hydroxides. The emulsion which settles between the heavier (bottom) EDC layer and the lighter (top) water layer in a tank can create deficiency in the stripping and distillation towers by causing fouling and corrosion. As indicated in Table 6.12, the amount of emulsified EDC varies from 2 to 4% and that of metal hydroxides from I to 15% by volume. 

Alumina membranes with a pore diameter of 0.2 pm have been tested successfully for removing emulsified EDC [Lahiere and Goodboy, 1993]. The soluble EDC, however, is not affected by the membrane treatment and remains at the same level before and after the operation. Pilot test results show that the water recovery is about 94%. The steady stale permeate flux from the pilot test at 30-45 C is 1290 Lfhr-m which is about 4 to 6 

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SJ1 Removal of Precipitated Heavy Metals Solids and Oils... 

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