Selection of wastewater treatment process based on the analytical hierarchy process and fuzzy analytical hierarchy process methods

Abstract

This paper presents an application of the analytical hierarchy process and fuzzy analytical hierarchy process methods for selecting the best wastewater treatment process. The analytical hierarchy process is one of the best ways for deciding among the complex criteria structure in different levels, and the fuzzy analytical hierarchy process is a synthetic extension of the classical method when the fuzziness of the decision makers are considered. After reviewing aerobic treatment processes operated in Iran's industrial estates and determining the main criteria used for treatment process evaluation, they are arranged in a hierarchy structure. Selection of the best wastewater treatment process is a multi-criteria decision making problem. Conventional methods are inadequate for dealing with the imprecise or vague nature of linguistic assessment. To overcome this difficulty, the fuzzy analytical hierarchy process is proposed for dealing with the vagueness of decision makers' judgments. The alternatives consist of extended aeration, absorption bio-oxidation, integrated fixed-film activated sludge, sequencing batch reactor, aerated lagoon. Based on the general condition of industrial estate's wastewater treatment plants, technical/administrative, economic and environmental criteria and their sub-criteria are weighted and then criteria evaluated and priorities of alternatives have been done by analytical hierarchy process and fuzzy analytical hierarchy process methods by the use of triangular fuzzy numbers. Finally, selection of the best process and ranking of these five processes are carried out by these foregoing methods, and some sensitivity analyses are conducted to show the results' sensitiveness to the changes of the weights of the evaluation criteria.

Decision making under uncertainty using a qualitative TOPSIS method for selecting sustainable energy alternatives

“…It evaluates the importance of each criterion in relation to the others in a hierarchical manner. The AHP method is based on structure of the model, comparative judgment of criteria and synthesis of the priorities (Karimi et al 2011). In the first step, a complex problem is broken into a hierarchy with goal as an objective, criteria and sub-criteria at levels and sub-levels like a family tree.…”

“…However, assessing and selecting the most suitable and sustainable types of energy in a geographical area is a complex problem. For governments and businesses, important decisions include whether to establish energy systems in a given place and deciding which energy source, or combination of sources, is the best option when considering potentially conflicting criteria including environmental, technical and economic aspects (Baños et al 2011;Karimi et al 2011). These criteria in energy problems involve different qualitative and quantitative variables and require specific techniques to aggregate and summarize assessments made in such complex situations.…”

Wastewater treatment systems selection inside watersheds by using multiobjective analysis

“…It should be noted that many of the criteria adopted by them were more recently used in sewage treatment systems selection processes employing multiobjective analysis techniques (KARIMI et al, 2011;KALBAR et al, 2012;HUNT, 2013;CORNELLI (2014); MOLINOS-SENANTE et al, 2015). Thus, for Cr01 to Cr09 criteria, the alpha and beta values required to calculate the indifference and preference thresholds were, respectively, 0.05 and 0.00; and 0.15 and 0.00.…”

Selecting a Sustainable Disinfection Technique for Wastewater Reuse Projects

“…This criterion evaluates not only the ability to eliminate pathogens, but also the ability to remove other undesirable contaminants. The efficiency of a process can be evaluated on past experience, and from full-scale plants or pilot-plant studies [23].…”