REMOVAL AND RECOVERY OF LEAD FROM WASTEWATER BY CRYSTALLIZATION IN A FLUIDIZED BED REACTOR

Abstract

Removal and recovery of lead from wastewater by crystallization of the metal carbonate in a fluidized bed reactor was investigated in this study. A lab scale fluidized bed reactor with a post filter was first developed. Optimum conditions for crystallizing lead carbonate have been studied in this system initially seeded with quartz sand. Total lead concentration in the effluent lower than 1 mg/L and the removal efficiency is higher than 99% were achieved under the optimum conditions for the wastewater with influent concentration of lead up to 50 mg/L. These parameters included operational pH 7 - 8, CT/Pb feed ratio of 3 mol/mol, lead load lower than 1000g lead/m2h, and hydraulic load less than 22 m/h. It was also found that the crystal deposited on the sand surface consisted of more than 98% of lead salt. Additionally the lead coated on sand surface can be easily recovered.