The application of a hybrid model for identifying and ranking indicators for assessing the sustainability of wastewater treatment systems

A novel fuzzy framework for technology selection of sustainable wastewater treatment plants based on TODIM methodology in developing urban areas

Optimal technology selection of wastewater treatment plants (WWTPs) necessitates the adoption of data-driven scientific approaches that satisfy the sustainability requirements of the urban ecosystem. Such approaches should be able to provide actionable insights to decision makers constrained by factors such as population growth, land scarcity, and loss of functionality of wastewater treatment plants. The framework in this study proposes a hybrid fuzzy multi-criteria decision making (MCDM) model consisting of the analytical hierarchy process (AHP) and the TODIM (an acronym in Portuguese of interactive and multi-criteria decision-making) by using alpha cut series which takes into account the risk aversion of decision makers (DMs) to overcome uncertainties of environmental conditions. The literature to date indicates that the study is the first to presents how a systematic decision-making process is approached by interpreting the interaction of criteria for the selection of wastewater treatment technology through the membership function of Prospect Theory. The proposed methodology reveals that the prominent reference criterion manipulates other sub-criteria according to the function of risk-aversion behavior. The fuzzy sets based on alpha cut series are employed to evaluate both the criteria weight and the rank of the alternatives in the decision-making process to obtain compromise solutions under uncertainty. The dominance degrees of the alternatives are achieved by fuzzy TODIM integrated with the fuzzy analytic hierarchy process (FAHP) which deals with the uncertainty of human judgements. According to the ranking results determined by the dominance degree of alternatives, anaerobic–anoxic–oxic (A2O) without pre-clarification was the most effective process in relation to the sludge disposal cost (C25) calculated as reference criteria. The ranking of four full-scale WWTPs in a metropolitan city of an EMEA country based on 24 sub-criteria listed under the four main criteria, namely the dimensions of sustainability, is used as a case study to verify the usefulness of the fuzzy approach. Motivated by the literature gap related to the failure to consider the psychological behavior of DMs in technology selection problem for wastewater treatment, it is discussed how the proposed hybrid MCDM model can be utilized by reflecting human risk perception in wastewater treatment technology selection for developing urban areas.

A Risk Assessment Model for Cyber-Physical Water and Wastewater Systems: Towards Sustainable Development

Cyber-physical systems (CPS) and their Supervisory Control and Data Acquisition (SCADA) have attracted great interest for automatic management of industrial infrastructures, such as water and wastewater systems. A range of technologies can be employed for wastewater treatment CPS to manage risks and protect the infrastructures of water systems and their wastewater against cyberattacks. In this paper, we develop a novel risk assessment framework, named RAF-CPWS, which perfectly estimates the risks of water and wastewater technologies. To do this, a multi-criteria group decision-making (MCGDM) approach is designed by neutrosophic theory to assess the risks of wastewater treatment technologies (WWTTs). The proposed approach evaluates the best WWTTs, considering various economic, environmental, technological and cybersecurity, and social factors. A decision-making trial and evaluation laboratory (DEMATEL) is employed to evaluate the significance of the adopted factors in a real testbed setting. The proposed approach contributes to a comprehensive measure of WWTTs through several factors, revealing its high sustainability and security in assessing the risks of cyber-physical water and wastewater systems.

Sustainability assessment of wastewater treatment systems using cardinal weights and PROMETHEE method: case study of Morocco

To cope with water scarcity, Morocco needs to integrate the reuse of treated wastewater fully into its water management strategies. However, this option imposes several concerns about the appropriate wastewater treatment system (WWTS) whose performance is balanced by technical, environmental, financial, and societal sustainability. To deal with these challenges, the present study aims to assess the sustainability of five WWTS using the cardinal (CAR) and PROMETHEE methods. After hierarchizing the criteria and identifying the WWTS, two separate surveys were performed in order to rank criteria and alternatives by preference strength. The delivered rankings were converted, then, respectively into cardinal weights (criteria) and cardinal scores (alternatives). The PROMETHEE rankings showed that the membrane systems are the most sustainable followed by trickling filters, while the infiltration-percolation is the least sustainable WWTS. The activated sludge and lagoon systems were incomparable using PROMETHEE I partial ranking, and they were both ranked in the third position of sustainability. In contrast, PROMETHEE II complete ranking favored the activated sludge than lagoon systems due to its slightly high net outranking flow. The stability intervals indicated that the weights of all criteria could not affect the two first actions, which is mainly due to the high precision and robustness of the CAR method in eliciting weights. Finally, each criterion affected variably the sustainability of WWTS according to their characteristics, but overall, the process efficiency is the key factor (21.07% of weight) to reaching higher sustainability levels in addition to gaseous emissions (12.41% of weight), flexibility (8.32% of weight), and energy requirement (7.50% of weight).

Ergonomics indicators: A proposal for sustainable process performance measurement in ergonomics

Process performance measurement (PPM) has become a challenging task for organisations, which have many various processes, in today's globalised world. This challenging task is also remarkable in ergonomics, and combining sustainability with ergonomics can provide beneficial solutions for assessing risks and providing ergonomically favourable conditions for human well-being. In this paper, new ergonomics indicators (EIs) are proposed, classified, and described in detail to overcome this challenge through a systematic literature review that integrates ergonomics and sustainability. By considering sustainability indicators (SIs) selected from the review, the proposed EIs are presented within a three-dimensional structure. This structure enables measuring the performance on various issues in an organisation such as occupational health and safety, decent work, technology, working conditions, employee empowerment and development, charities, innovations, and recycling. Through systematic measurements using these indicators, more traceable and manageable processes can be achieved. Hence, ergonomists or managers can identify and prevent risky conditions practically. Practitioner Summary: This paper proposes ergonomics indicators and detailed descriptions for ensuring sustainable process performance measurement in ergonomics. The sustainability indicators presented as references for these proposals are utilised through selection and consolidation from literature. The ergonomics indicators are structured within a sustainability framework that considers six sustainability sub-dimensions proposed for ergonomics.

A multi-stage fuzzy decision-making framework to evaluate the appropriate wastewater treatment system: a case study

Selection of appropriate treatment processes for wastewater treatment (WWT) plants at the design stage involves a careful examination of different economic, environmental, and social parameters. Designers and decision-makers seek a compromise among such conflicting elements, which can be facilitated by decision support tools that are adapted for the ambiguity of individual opinions and decision parameters. This study aims to improve the qualification and efficiency of decision-making in WWT processes. A multi-stage framework is proposed to help select investments, technology, appropriate technology-specific system, and companies that apply such systems. The framework combines the Analytic Hierarchy Process (AHP), Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE), cash flow analysis, and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) within fuzzy logic. The main contribution is the description and formation of an integrated framework to guide businesses and researchers for the evaluation of several WWT decision processes. To the best of the authors' knowledge, no study in the literature fuses multiple stages of this WWT process with the proposed approaches.

Multi-period evaluation and selection of rural wastewater treatment technologies: a case study

Rapid population growth and agricultural development are generating a considerable amount of effluents, which poses threats to the quality of rural water resources as well as sanitary conditions. However, with a range of rural wastewater treatment (WT) technologies available, one major problem facing the practitioners is which to choose as the most favorable option suited to specific areas. In this study, a novel decision-making framework is proposed to evaluate and select the optimal alternative in rural areas of Xi'an within multiple consecutive time periods. Firstly, an evaluation index system is constructed and picture fuzzy numbers (PFNs) are used to represent both evaluation levels and experts' refusal due to limitation of knowledge. Secondly, fuzzy analytical hierarchy process (FAHP) is applied to derive weights of criteria, which enables experts to assign fuzzy numbers to express their preferences for comparison judgments. Thirdly, evidence theory is utilized to obtain the aggregated values from multiple time periods. Finally, based on the belief intervals obtained, sequencing batch reactor (A₄) is determined as the optimal rural WT technology in Xi'an from 2006 to 2020, whereas the membrane bio-reactor (A₂) is the last option. The effectiveness of the proposed framework is further validated by comparative analysis. This research can hopefully serve as useful guidance for the assessment of rural WT technologies in various regions.

Intuitionistic fuzzy analytical hierarchical processes for selecting the paradigms of mangroves in municipal wastewater treatment

Municipal wastewater discharge is widespread and one of the sources of coastal eutrophication, and is especially uncontrolled in developing and undeveloped coastal regions. Mangrove forests are natural filters of pollutants in wastewater. There are three paradigms of mangroves for municipal wastewater treatment and the selection of the optimal one is a multi-criteria decision-making problem. Combining intuitionistic fuzzy theory, the Fuzzy Delphi Method and the fuzzy analytical hierarchical process (AHP), this study develops an intuitionistic fuzzy AHP (IFAHP) method. For the Fuzzy Delphi Method, the judgments of experts and representatives on criterion weights are made by linguistic variables and quantified by intuitionistic fuzzy theory, which is also used to weight the importance of experts and representatives. This process generates the entropy weights of criteria, which are combined with indices values and weights to rank the alternatives by the fuzzy AHP method. The IFAHP method was used to select the optimal paradigm of mangroves for treating municipal wastewater. The entropy weights were entrained by the valid evaluation of 64 experts and representatives via online survey. Natural mangroves were found to be the optimal paradigm for municipal wastewater treatment. By assigning different weights to the criteria, sensitivity analysis shows that natural mangroves remain to be the optimal paradigm under most scenarios. This study stresses the importance of mangroves for wastewater treatment. Decision-makers need to contemplate mangrove reforestation projects, especially where mangroves are highly deforested but wastewater discharge is uncontrolled. The IFAHP method is expected to be applied in other multi-criteria decision-making cases.