A new framework for small drinking water plant sustainability support and decision-making.

Public drinking water system decisions about treatment processes are becoming more challenging, especially as regulations become more stringent and source water quality degrades. For small systems that serve <10,000 people, treatment decisions are particularly difficult due to limited resources and because they do not currently have resources to help them make informed and sustainable decisions using environmental, social, and economic criteria. Therefore, a user-friendly sustainability assessment framework, which compares treatment processes relevant to a wide variety of small drinking water systems, was constructed. In summary, the framework uses life cycle assessment and multiple-criteria decision analysis to comprehensively evaluate twelve decision criteria, developed specific to small drinking water systems; the framework then uses an aggregation approach to identify and navigate multiple trade-offs and make a final recommendation based on stakeholder values. Four hypothetical scenarios were examined to show the framework's applicability to diverse small systems, ability to help stakeholders navigate trade-offs, and engineering relevance. The framework is universal in its capacity to evaluate systems with different design parameters, source waters, treatment criteria, and stakeholder preferences.