Reducing non-residential asset sanitisation water footprint for improved public health in water-deficient cities

Abstract

• Access to water-based sanitisation is disproportionately distributed in cities. • UV-based technology offers sustainable solution for sanitising public assets. • Long-term pandemic preparation requires alternative to water-based sanitisation. • Balancing public health sanitisation water footprint needs strategic planning. This paper evaluates the potential for reconfiguring city-scale clean water demand by reducing the non-residential asset sanitsation water footprint. A novel methodological framework is proposed for assessing the feasibility of a mix of three surface sanitisation measures (Manual surface wiping, Mechanical cleaning/Rapid disinfectant spraying, Ultraviolet germicidal irradiation-UVGI treatment) in terms of a Sanitisation waterfootprint index (SWI); three typical application scenarios are considered – high risk-high frequency, moderate risk-moderate frequency, moderate risk-low frequency. The UVGI treatment outperforms the other two surface treatment methods, particularly in high risk-high frequency scenario in the healthcare setting, with SWI as low as 2%. Further, case-study evidence from a ward-level spatial analysis using real-world data estimates SWI ranging between 0-30% in those wards with greater commercial/public assets, showing clear merit of this framework in re-configuring city-scale public health sanitisation water footprint. A cost-benefit analysis (involving resources – staffing, water and chemicals; capital expenditure, and energy costs) shows superior performance of UVGI treatment over the other two methods from the second year onwards, surpassing the initial cost-effectiveness for corresponding manual or mechanical cleaning. Wider implementation of this framework can foster strategic transformation of city-scale water footprint, which is deemed essential for ensuring sustainable growth of water deficient cities globally.