Indicators for sustainability assessment of small-scale wastewater treatment plants in low and lower-middle income countries

Wastewater treatment in low and lower-middle income countries is often limited by lack of local technical expertise, institutional capacity, and financial resources, making it challenging to reach SDG6-target 6.3, i.e. halving the proportion of untreated wastewater. Several studies suggest sets of sustainability indicators for assessing the planning and/or operation of WWTPs. However, existing standard indicators are typically focused on the context of high and upper-middle income countries, whereas low and lower-middle income countries face other types of issues. The development of a contextualized set of relevant and effective sustainability indicators to support the planning and/or operation of small-scale WWTPs in low and lower-middle income countries is crucial. This study develops a contextualized set of sustainability indicators for small-scale wastewater treatment plants in Bolivia, which is classified as a lower-middle income country. Indicators were identified using a literature review combined with empirical studies using focus groups with managers and operators, as well as, workshops with experts. The aim of the focus groups and workshops was to acquire an understanding of the local context and identify relevant sustainability indicators. The practical investigation took place at five sites in Cochabamba, Bolivia. The results suggest that sustainability assessment of WWTPs in low and lower-middle income countries should emphasize the institutional dimension (e.g. Institutional capacity, Interactions, and Information) and the technical dimension (e.g. Sewage network functionality and Expertise) alongside indicators in the social, economic and environmental dimensions.