To evaluate the potential use of the bacterial alginate extracted from excess activated sludge as a sustainable copper bioadsorbent, dried alginate‐Ca made from municipal excess activated sludge was characterized by atomic force microscopy, and tested in a batch system. The alginate‐Ca yield from the activated sludge was 103 ± 15 mg g⁻¹. The maximum Cu²⁺ uptake was 41.96 mg g⁻¹. Accumulation of Cu²⁺ reached equilibrium within 50 min and followed the Langmuir adsorption isotherm. The solution pH and initial Cu²⁺ concentration were critical for Cu²⁺ biosorption. Thesludge alginate‐Ca bioadsorbent could be regenerated by 100 mmol L⁻¹ HCl with 82% Cu²⁺ recovery. Calcium alginate from excess activated sludge was proved to be a good bioadsorbent for heavy metal elimination.