Reuse of nutrients and water from municipal wastewater is attracting increasing attention. However, pollutants such as toxic metals should be minimised. This study investigated the potential for reducing metal concentrations in wastewater effluent and secondary sludge by introducing sludge-derived char (SDC) as a sorbent in primary settling. Batch experiments, performed in aqueous metal solution and wastewater, showed that Cu and Ni removal was significantly reduced in wastewater containing dissolved organic matter (68% and 40%, respectively), compared to metal solution (>99% and 99%, respectively). Modelling of primary settling indicated Cd and Cu removal enhancement with SDC addition (from 39%–79% and 30%–43%, respectively). Smaller effects were observed for Pb, Cr, and Zn. An increased risk of Ni concentration in primary settler effluent was identified (−53% removal). These results demonstrate the challenges of implementing SDC as a sorbent for real wastewater.