Life cycle assessment (LCA) has been widely used to quantify environmental impacts associated with urban water infrastructure, including wastewater, drinking water, stormwater, and integrated urban water systems. While LCA is applicable for the estimation of global environmental impacts, decision-makers must balance these impacts with local, often regulated, environmental and public health objectives. To characterize the state of the art for the use of LCA for urban water infrastructure, a thorough literature review was conducted of papers that applied LCA to wastewater (173 papers), drinking water (44 papers), stormwater (17 papers), and integrated urban water (22 papers) systems. Analyses revealed current preferences for functional unit basis (e.g., volume for wastewater), system boundaries (e.g., focus on operation), and impact assessment methodology (CML, ReCiPe, and Eco-Indicator). Based on these findings, LCA methodological recommendations for urban water infrastructure are made, and emerging opportunities to balance objectives and inform comprehensive decision-making are discussed. Critical opportunities include the integration of spatial considerations (e.g., spatialized characterization factors), water quantity (e.g., water quantity indicators), public health (e.g., integration with risk assessment), economic and social assessments (e.g., life cycle costing and social LCA), along with prioritization of continuous stakeholder engagement. Finally, research and development needs specific to the use of LCA for urban water infrastructure (e.g., development of new indicators coupled with case studies) are prioritized.

The pursuit of sustainability has catalyzed broad investment in the research, development, and deployment (RD&D) of innovative water, sanitation, and resource recovery technologies, yet the lack of transparent and agile methodologies to navigate the expansive landscape of technology development pathways remains a critical challenge. This challenge is further complicated by the higher levels of uncertainty that are intrinsic to early-stage technologies. In this work, we review and synthesize published literature on the sustainability analyses of water and related technologies to present quantitative sustainable design (QSD) – a methodology to expedite and support technology RD&D. With a shared lexicon and a structured approach, QSD facilitates interdisciplinary communication and research consistency. In introducing QSD, we review existing studies to highlight best practices and discuss them in the context of the specific steps of QSD, which include defining the problem space, establishing simulation algorithms, and characterizing system sustainability across economic, environmental, human health, and social dimensions. Next, we summarize tools for QSD execution and provide recommendations to account for uncertainty in this process. We further discuss applications of QSD in the fields of water/wastewater and beyond (e.g., renewable fuels, circular economy) in combination with uncertainty, sensitivity, and scenario analyses to generate the desired types of insight. Finally, we identify future research needs for sustainability analyses to advance technology RD&D. Ultimately, QSD can be used to elucidate the complex and intertwined connections among design decisions, technology characteristics, contextual factors, and sustainability indicators, thereby supporting transparent, consistent, and agile RD&D.

Objectives: The objectives of this work were to evaluate (i) the prevalence and frequency of caregiver‐reported soil ingestion by children, (ii) whether household flooring material in the bedroom (earthvs. concrete) affected caregiver‐reported soil ingestion, (iii) whether caregiver‐reported soil ingestion was associated with caregiver‐reported diarrhoea and (iv) caregivers’ perceptions of their children ingesting soil.Methods: We conducted 309 household surveys in northern Ghana, including 529 children under five (249 children aged 6–36 months), and measured faecal contamination in soil from 31 households.Results: Among all children, 15% were reported to have directly ingested soil in the past week, including 28% of children aged 6–36 months. Among children reported to have ingested soil, the median frequency was 14 times in the past week, and the median amount of soil ingested each time was half a handful. There was no association between household floor material and whether the caregiver observed a child directly ingesting soil. After adjusting for household floor material and other potential confounding variables, caregiver‐reported soil ingestion was associated with caregiver‐reported diarrhoea for children under five [adjusted odds ratio (adj.OR) = 3.13, 95% confidence interval (CI) 2.76–3.55] and children aged 6–36 months (adj.OR= 2.61, 95%CI2.01–3.39). Approximately 83% of caregivers whose children ingested soil reported they thought it was unsafe and were more likely to report stopping their child from ingesting soil, but these responses did not affect the quantity of soil ingested.Conclusions: Our results suggest direct soil ingestion is associated with diarrhoea independent of household floor material, and separate interventions may be necessary to prevent exploratory soil ingestion.