Exploring technological alternatives of nutrient recovery from digestate as a secondary resource

The growing volume of anaerobic digestate makes its sustainable reuse increasingly important and challenging. This study examines both established and emerging technologies that treat digestate as a secondary resource for nutrient recovery. A review of digestate composition showed large variations in nutrient content, with nitrogen ranging from 1.6–21% and phosphorus from 0.1–3.5% (dry basis). These levels highlight its potential as a feedstock for producing higher-value bio-based fertilizers within circular, zero-waste systems. The collected knowledge was then used to design two integrated biorefinery scenarios capable of converting digestate into bio-based products for new supply chains.