Oilfield-produced water (PW), the largest by-product of petroleum extraction, presents significant treatment challenges due to high concentrations of total dissolved solids, heavy metals, and organic compounds. In this study, a ureolytic bacterium Staphylococcus succinus J3, with efficient petroleum degradation and microbially induced calcite precipitation (MICP) capabilities, was screened for simultaneous removal of hardness ions and organic pollutants from PW. Strain J3 showed excellent removal of Ca