The management of sludge originating from wastewater treatment plants is a highly complex and costly activity, crucial for maintaining environmental and sanitary advantages expected from treatment systems. Recognizing its significance, Agenda 21 addressed environmentally sound management of solid wastes and sewage-related issues, emphasizing reduction in production, maximizing reuse and recycling, and promoting environmentally sound treatment and disposal practices (Cieślik et al. in J Clean Prod 90:1–15, 2015).