Abstract

SOTO, Eduardo; MIRANDA, Rosa del C; SOSA, César A  and  LOREDO, José A. Optimization of the Removal Processs of Heavy Metals from Raw Water of Galvanic Industry by Chemical Precipitation. Inf. tecnol. [online]. 2006, vol.17, n.2, pp. 33-42. ISSN 0718-0764.  doi: 10.4067/S0718-07642006000200006.

The aim of this research was to obtain the optimum conditions to remove heavy metals from wastewaters of the galvanic industry, which contain chromium (435 mg/L), zinc (720 mg/L), iron (168 mg/L) and nickel (24 mg/L). The treatment was made by chemical precipitation using caustic soda to set pH and ferric chloride like coagulant aid in jar test. The responses to optimize are: flocculation time, stirring speed and coagulant dose. The optimum conditions to remove heavy metals from synthetic wastewater was, flocculation time: 7 minutes, stirring speed: 18 rpm, coagulant dose: 11.8 mL and flocculation time: 9.5 minutes,stirring speed: 30 rpm, coagulant dose: 5.2 mL for raw wastewater. The treatment conditions were different for the raw wastewater because the raw wastewater contains other pollutants which over charge the colloidal surface and affects the flocculation processes

Keywords : heavy metals; chemical precipitation; wastewater water; galvanic industry.