Treated sewage sludge is often reused as a fertilizer but several European countries are phasing out this option due to concerns about harmful substances in the sludge. Valuables in the sludge should still be recycled so the removal of the pollutants is necessary. The technology in sewage sludge treatment remained nearly unchanged in the past century. Adapting traditional treatments and combining them with upcoming ones can be a way to separate substances in sewage sludge. This work discusses examples of how treatment methods can be combined and which potential these treatment combinations may have. New tools for system analyses need to be developed to allow the integration and adaption of treatments into existing infrastructure.