Risk assessment for wastewater treatment facilities using integrated picture fuzzy based AHP-DEMATEL decision support system

The gradual depletion of water resources and the increasing amount of wastewater are consequences of population growth, urban expansion, and industrialization. Wastewater Treatment Facilities (WWTFs) are instrumental in overcoming global challenges such as drought and water scarcity by ensuring the effective use of water resources. However, they encounter challenges such as equipment failures, process disruptions, insufficient monitoring, and exposure to hazardous substances. The literature lacks comprehensive studies that evaluate the significance of risk factors in WWTFs and their interrelations using Multi-Criteria Decision-Making (MCDM) methods. For this reason, this study aims to identify potential risks and to uncover their relative importance and interdependencies through a decision-support system constructed by integrating Picture Fuzzy Analytic Hierarchy Process (PiF-AHP) and Picture Fuzzy DEcision-MAking Trial and Evaluation Laboratory (PiF-DEMATEL). Picture Fuzzy Sets (PiFSs) are utilized for their ability to represent not only positive and negative opinions of experts but also hesitation and refusal, allowing a more accurate and realistic modeling of uncertainty compared to other fuzzy set extensions. Accordingly, risk factors are grouped into four Main categories with 22 sub-risks, and their importance Weights are calculated using the PiF-AHP. To focus on the most critical risks, those with an importance weight above 3% are selected using the threshold value approach commonly applied in MCDM studies. These selected risks are then analyzed with the PiF-DEMATEL method to uncover the interdependencies among these factors. The results show that the most prominent risks in WWTFs are related to public health, natural disasters, fire, explosion, and environmental threats. In particular, natural disasters and insufficient occupational safety measures are identified as the most influential causal factors, while risks such as pollutant release and infection emerge as critical effect factors. This integrated approach enables a comprehensive assessment of risks in WWTFs. It helps reduce accidents, protect worker health, support facility performance, and ensure operational safety.