EVAS - a practical tool to assess the sustainability of small wastewater treatment systems in low and lower-middle-income countries
Journal article, 2020

Small wastewater treatment systems (WWTSs) in low and lower-middle income countries still face challenges to achieve optimal performance and acceptable levels of sustainability. Thus, a practical tool, easy to apply by locals, to diagnose the actual status of WWTSs is required in order to identify weak areas for further improvement. This study presents a sustainability assessment tool, EVAS (EVAluaciĆ³n de Sostenibilidad: EVAluation of Sustainability), for small WWTSs in low and lower-middle income countries. The EVAS tool is developed based on a set of contextualized sustainability indicators and sub-indicators in five dimensions (technical, environmental, social, economic, institutional). Each indicator or sub-indicator is broken down into factors, each associated with specific targets to fulfil, and scored using a traffic light scale (0 to 4) indicating unsustainable-low-medium to high levels of sustainability. The tool was developed taking into consideration that local data may sometimes be incomplete and encourages the collection and monitoring of relevant data. The assessment results support local managers or other stakeholders responsible for wastewater management with the identification of weaknesses that need to be addressed. The tool was tested using two case studies involving WWTSs in Bolivia. One WWTS received a medium sustainability rating, whereas the other system received a low sustainability rating, which indicates that several improvements are required in all sustainability dimensions. Stakeholders in the case studies found the tool useful, and suggested ways in which it could be further improved. It is expected that the application of this tool can contribute to raising the sustainability level of small WWTSs in low and lower-middle-income countries.

EVAS tool

Wastewater treatment

Decision support

Sustainability indicators

Capacity building

Local stakeholders


Claudia Cossio Grageda

Chalmers, Architecture and Civil Engineering, Water Environment Technology

University of San Simón

Jennifer R Mc Conville

Swedish University of Agricultural Sciences (SLU)

Ann Mattsson


Chalmers, Architecture and Civil Engineering, Water Environment Technology

Alvaro Mercado

University of San Simón

Jenny Norrman

Chalmers, Architecture and Civil Engineering, Geology and Geotechnics

Science of the Total Environment

0048-9697 (ISSN) 1879-1026 (eISSN)

Vol. 746 140938

Subject Categories

Social Sciences Interdisciplinary

Environmental Management

Environmental Analysis and Construction Information Technology





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