Sustainable methodical approaches to recycling sludge waste: value-added products, and their agricultural applications

Purpose: This review addresses the important global issue of increased sludge accumulation from wastewater treatment plants, which poses serious environmental challenges due to heavy metals and high levels of organic pollution. The study provides a thorough review of sludge-to-value-added product recovery methods, including anaerobic digestion, composting, vermicomposting, and pyrolysis. Method: The review highlights recent advances and examines the strengths and weaknesses of each approach. Given the significant loss of organic components before sludge generation, a unified strategy for value-added product recovery management is crucial, as the study emphasizes. Results: The study provides important standards for choosing the best technique for sustainable sludge management from a waste-to-resources standpoint. Conclusion: The study shows sewage sludge's potential as a valuable organic resources with higher nutrient compositions (Nitrogen 2.5 5.5%, Phosphorus 0.8 2.5%, Potassium 1.5 3.5%, Calcium 1.2 4.5%, and Magnesium 0.3 0.8% respectively) and its possible uses in agriculture.