How Does Scale of Implementation Impact the Environmental Sustainability of Wastewater Treatment Integrated with Resource Recovery?

Energy and resource consumptions required to treat and transport wastewater have led to efforts to improve the environmental sustainability of wastewater treatment plants (WWTPs). Resource recovery can reduce the environmental impact of these systems; however, limited research has considered how the scale of implementation impacts the sustainability of WWTPs integrated with resource recovery. Accordingly, this research uses life cycle assessment (LCA) to evaluate how the scale of implementation impacts the environmental sustainability of wastewater treatment integrated with water reuse, energy recovery, and nutrient recycling. Three systems were selected: a septic tank with aerobic treatment at the household scale, an advanced water reclamation facility at the community scale, and an advanced water reclamation facility at the city scale. Three sustainability indicators were considered: embodied energy, carbon footprint, and eutrophication potential. This study determined that as with economies of scale, there are benefits to centralization of WWTPs with resource recovery in terms of embodied energy and carbon footprint; however, the community scale was shown to have the lowest eutrophication potential. Additionally, technology selection, nutrient control practices, system layout, and topographical conditions may have a larger impact on environmental sustainability than the implementation scale in some cases.