Technical, environmental, and economic assessment of anaerobic digestion of pre-treated municipal organic waste for energy production and reuse of liquid digestate

Biomass conversion and upcycling are key to the transition toward sustainable energy production and the circular use of bioresources, requiring effective utilization of all biomass fractions. This study provides an integrated technical, environmental, and economic assessment of anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), coupling biogas production with greenhouse reuse of the digestate liquid fraction. Untreated OFMSW and OFMSW subjected to physical (hydrodynamic cavitation) and enzymatic pre-treatments were evaluated as AD feedstocks at laboratory and upper scales. The resulting liquid digestate was characterized and tested in greenhouse trials to assess its agronomic performance. Life cycle assessment (LCA) and cost-benefit analysis were conducted to evaluate the environmental and economic feasibility of the integrated system.Results pointed out that pre-treated OFMSW outperformed untreated OFMSW in terms of biogas and methane yields, with hydrodynamic cavitation demonstrating superior scalability and resilience at the upper scale. The digestate liquid fraction proved to be highly effective for greenhouse fertigation, achieving plant biomass yields comparable to mineral fertilizers. LCA identified nutrient supplementation as the primary environmental hotspot (>60% of total impacts), whereas economic analysis showed physical pre-treatment to be the most cost-effective option, increasing net present value by 30–45% over enzymatic pre-treatments due to lower energy and input requirements.This research demonstrates that AD integrated with effective pre-treatments and liquid digestate exploitation can operate as a sequential biorefinery, enabling simultaneous waste conversion, renewable energy production, and nutrient recycling, thereby improving bioresource circularity and reducing dependence on fossil-based fertilizers.