Treatment and disposal of sewage sludge from wastewater in a circular economy perspective

The sewage sludge (SS) management represents one of the key issues to be properly addressed in view of achieving resource recovery from wastewater treatment plants and cost effectiveness operations. Several efforts must be performed to overcome the existing bottlenecks: (1) stringent laws on environmental protection, (2) increase production due to the growth of treated civil wastewater production, (3) micropollutants and heavy metals presence in sewage sludge, and (4) improper applied technology for sludge recovery. Europe is adopting a circular economy model, where sludge is a resource to be exploited. However, some European directives are contradictory and/or not adequate to favor the sludge reuse. Furthermore, in the scientific literature there are still doubts about the risks of sludge reusing. The chapter explores the key issues surrounding the sewage sludge management and reuse in view of providing an overview to the current situation on this topic.