Quantifying benefits of resource recovery from sanitation provision in a developing world setting

Abstract

Despite concerns of sanitation provision, water scarcity, climate change, and resource depletion, limited research has been conducted to assess the environmental impact of wastewater treatment and resource recovery strategies to improve access to sanitation and resource utilization in developing world settings. Accordingly, the goal of this study is to evaluate the potential benefits of mitigating the environmental impact of two small community-managed wastewater treatment systems in rural Bolivia using resource recovery (i.e., water reuse and energy recovery). Life Cycle Assessment (LCA) is used to estimate the embodied energy, carbon footprint, and eutrophication potential of these systems under existing and resource recovery conditions. Two distinct technologies are analyzed: (1) an upflow anaerobic sludge blanket reactor (UASB) followed by two maturation ponds in series (UASB-Pond system) and (2) a facultative pond followed by two maturation ponds in series (3-Pond system). For the existing systems, bathroom and collection infrastructure had a higher energy intensity than the treatment processes, whereas direct methane emissions from treatment were the primary contributors to the carbon footprint. Taking advantage of reclaimed water was found to greatly reduce the eutrophication potential for both systems, in which the reduction increases proportionally to the percentage of water that is reclaimed. Energy recovery from the UASB-Pond system provided a 19% reduction in embodied energy and a 57% reduction in carbon footprint. Combining water reuse and energy recovery for the UASB-Pond system reduced the eutrophication potential, embodied energy and carbon footprint simultaneously. This highlights the benefits of integrated resource recovery.

Keywords: Carbon footprint; Eutrophication potential; Millennium development goals; Nutrients; Small-scale sewage systems; Sustainability.