Quantification of Carbon Emissions in Potable Reuse Treatment Configurations

Potable reuse commonly employs reverse osmosis (RO). However, RO has high energy requirements and generates a brine waste, making it better suited for coastal locations that allow for oceanic brine discharge. Carbon-based advanced treatment (CBAT) offers a more favorable option for inland regions, with lower capital costs, energy requirements, and no brine waste. This study quantified carbon emissions over a 50-year operational period for three configurations: RO with oceanic brine discharge, RO with zero-liquid discharge (ZLD) brine handling, and CBAT. Results showed that RO and pumping energy accounted for over 80% of Scope 2 emissions in RO trains, and ZLD brine treatment increased emissions by 60%. Alternatively, CBAT had 3x lower Scope 2 emissions, but Scope 3 emissions could be substantial depending on the type and replacement frequency of the granular activated carbon. By understanding carbon emissions, decision-makers can balance meeting potable reuse requirements while minimizing the carbon impact