抄録
API separator sludge is usually present in wastewater treatment plants of refinery and must be treated properly. The recovery of light components from the sludge containing water, oil and solid was investigated by means of chemical treatment. Surfactant and electrolyte were used to recover the oil from the solid surface and destabilize the oil droplets, respectively. Ferric salt was used as a coagulant to reduce the electrostatic repulsion of the oil droplets. Polyelectrolytes were used to flocculate these oil droplets in the system. The effect of several parameters on the recovery was observed, namely, (1) the type and concentration of surfactant, (2) the concentration of electrolyte, (3) the concentration of both coagulant and flocculant, (4) pH of the solution and (5) the presence of the nonionic surfactant Empilan KB-7. It was found that the surfactant and electrolyte system requires very high concentration of surfactant and electrolyte which results in the economic and corrosion problems. On the other hand, the use of polyelectrolyte together with flotation technique is preferable for chemical treatment because the maximum recovery, 90-99.7%, could be achieved with a small amount of polyelectrolyte. The optimum dosages are approximately 5-20 mg/l of polyacrylamide.
