Emerging Waste Valorization Pathway with Aerobic Granular Sludge: Prospective Life Cycle Assessment for Türkiye

To address the environmental burdens of wastewater generation and fossil-based economy, application of aerobic granular sludge (AGS), which entails bio-resource recovery and wastewater treatment can be promising. Recognizing AGS technology as a sustainable waste management solution requires a robust assessment of its environmental performance relative to conventional pathways. Prospective environmental impacts of two AGS-based wastewater treatment configurations were evaluated in the context of Türkiye: (1) AGS with primary settling and an external membrane (PS-AGS-EM), (2) AGS with an external membrane (AGS-EM), where both enable recovery of polyhydroxyalkanoates, extracellular polymeric substances and biogas. From a consequential assessment perspective, operation of AGS configurations with an average of -0.3 kg CO₂eq. per m³ wastewater demonstrated to be more favorable compared to the activated sludge and membrane bioreactor with 1.26 kg CO₂eq. and 0.8 kg CO₂eq. per m³ wastewater, respectively. Consumption of electricity was the major hotspot in both AGS configurations, especially for AGS-EM with almost 50% contribution to global warming potential and freshwater eutrophication potential categories. Under a wastewater management functional unit and assuming high substitution rates of conventional polymers by recovered biopolymers, AGS-EM configuration demonstrated superior environmental performance despite higher energy and chemical demands. Conversely, when EPS production was considered as the functional unit, PS-AGS-EM performed more favorably due to its lower energy and chemical requirements and higher biogas recovery potential. In the endeavors towards sustainable phasing out of fossil-based polymers and efficient water treatment strategies, the outcomes of the present AGS resource recovery study can provide an environmentally enlightening guideline.