The Biofactory: Life Cycle Sustainability Assessment for Wastewater Biorefineries

Furness,M. (University of Canterbury, Pontificia Universidad Católica de Valparaíso), Bello Mendoza R. (University of Canterbury), Chamy Maggi, R. (Pontificia Universidad Católica de Valparaíso)

The circular economy offers an opportunity for wastewater to be utilized as a valuable resource within the increasingly scarce global food-water-energy nexus. Many promising technologies for recovering resources, such as biogas, bio solids and nutrients, and improving effluent quality, from wastewater have been implemented across the world. Life Cycle Assessment (LCA) studies of these technologies demonstrate improved environmental impacts to promote their implementation, however, this tool is difficult for decision makers to interpret due to the diverse range of environmental impacts. LCA also fails to address sustainability trade-offs between additional economic and socio-cultural factors that influence decisions regarding the implementation of resource recovery in wastewater treatment plants (WWTPs). Life Cycle Sustainability Assessment (LCSA) is a tool that can compare alternative technologies across integrated aspects of sustainability, combining LCA, Life Cycle Costing (LCC) and Social Life Cycle Assessment (SLCA). The knowledge surrounding the application of this model to WWTPs and circular economies is limited. This study implements the monetization of LCSA for two real wastewater resource recovery plants referred to as The Bio-factories 1 and 2. Considering a 44,500 kg BOD5/day p.e. of wastewater treated functional unit, each Biofactory was assessed under four scenarios expanding system boundaries across 1. Water Recovery, 2. Biosolids Recovery, 3. Energy Recovery; and 4. Advanced Nitrogen removal, comparing the environmental and economic benefits of different technologies.