Abstract

Copper-containing wastewaters is a serious problem to the environment. The microbe-induced carbonate precipitation (MICP) is a novel process in the heavy metal-containing wastewater treatment. In this study it was evaluated the bacteria (factor 1) and the calcium (factor 2) role, and the optimum pH (factor 3) on copper precipitation through MICP applying the bacteria strain Sporosarcina pasteurii and an experimental design 23, where copper removal was the response variable. The copper precipitation stage was separated from the bacterial culture to assure bacterial survival and a maximum urea hydrolysis. Through an ANOVA of the results, none of the three factors evaluated influence on the copper precipitation. The copper removal obtained were 50-60%. The bacteria cells would not act as nucleation site according to SEM images. The copper co-precipitation with calcium did not take place. The neutral pH evaluated was easily obtained from the mix of the alkaline bacterial culture and the acid copper solution. Through SEM-EDX and FTIR analysis, the precipitates composition was defined as malachite, a valuable by-product. Finally, the bacteria role remains on carbonate ions production, but not on copper precipitation, neither calcium presence. Future research is required to improve copper removal through MICP to compete with traditional technologies.