Bio-Based Fertilisers from Sewage Sludge: Quality, Safety, and Circular Agriculture

Bio-based fertilisers (BBFs) derived from sewage sludge and other organic waste streams enhance soil fertility, reduce dependency on imported mineral fertilisers, and support circular economy goals. This document evaluates their agronomic efficiency, environmental safety, and economic feasibility across diverse European climates and soil types. Field trials assess nutrient availability, crop growth (wheat, ryegrass), and residual fertilisation value, with focus on phosphorus and nitrogen recovery. Key concerns include contaminant limits (heavy metals, antibiotics), ammonia emissions during processing, and variability in nutrient content. BBFs improve soil organic carbon and microbial activity but require optimised application to prevent leaching and eutrophication. Regulatory frameworks such as the Fertilising Products Regulation (FPR) and national End-of-Waste criteria ensure quality and safety. Results inform regional nutrient management strategies, emphasising sustainable recovery technologies, logistics, and policy support for market uptake.