DEVELOPMENT OF A COMPOSITE INDEX OF SUSTAINABILITY FOR WASTEWATER TREATMENT PLANTS

Abstract

Purpose: The research aims to develop a Composite Index of Sustainability for Wastewater Treatment Plants (CSI-WWTP), with numerical representation, aggregating three indicators: Environmental Sustainability (ESI), Economic Sustainability (ECI), and Social Sustainability (SSI). Methods: The calculation of CSI-WWTP was developed using multicriteria analysis to aggregate dimensions with the weighted average method. It was used to define the relevant criteria for building the indicators and the index, data from wastewater treatment plants that uses Up flow Anaerobic Sludge Blanket (UASB) operated by a Sanitation Company in Brazil, and dates related research found in the literature. Results and discussion: CSI-WWTP was applied in 16 wastewater treatment plants with data from 2018 to 2021, aiming to rank the systems in terms of sustainability. The weights of dimensions and criteria were assigned by the authors and tested with different scenarios. The result allowed ranking the WWTP in terms of their sustainability and graphically identifying the dimension that most impacted the result. Implications of the research: The limitation of the study is related to the use of only one wastewater treatment technology. Originality/value: This tool is an important decision support instrument for sanitation company managers, allowing the identification of WWTP sustainability weaknesses, and systems that require greater investment. It can also be used as a basis for implementing a WWTP sustainability program, promoting healthy competition among operators. It is a tool that works with operational data usually monitored, allowing scenario analysis with different weight assignments for dimensions and criteria according to the decision-making group's evaluation, indicating its versatility.