Environmental optimization of chromium recovery from tannery sludge using a life cycle assessment approach

► Chromium recovery from tannery sludge was environmentally evaluated by means of LCA. ► Energy and chemical use increase the environmental impact of end-of-pipe treatment. ► Method is environmentally better in case of higher chromium concentration in sludge. ► Anaerobic digestion of tannery sludge considerably improved the environmental profile.