Evaluation of remedial countermeasures using the analytic network process M.A.B. Promentilla * , T. Furuichi, K. Ishii, N. Tanikawa Laboratory of Solid Waste Resources Management Engineering, Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan Accepted 18 November 2005 Available online 18 January 2006 Abstract The aim of this paper is to present an evaluation method to aid decision makers in the prioritization and selection of appropriate countermeasures at the planning stage of site remediation. We introduced a hierarchical network (hiernet) decision structure and applied the Analytic Network Process (ANP) supermatrix approach to measure the relative desirability of the remedial alternatives using the decision maker’s value judgment as input. A simplified illustrative example is presented to elucidate the process, as it is being applied to evaluate the feasible remedial countermeasures of a contaminated site caused by uncontrolled landfill. Four decision models derived from the generalized hiernet were examined to describe the effect of hierarchic functional dependence, inner dependence and feedback cycle on the derivation of the priority weights. The ANP could provide a more flexible analytical framework to break down one’s judg- ment through a more elaborate structure in a systematic way to understand the complexity of the decision problem. The proposed method therefore may not only aid in selecting the best alternative but also may help to facilitate communication to understand why an alternative is preferred over the other alternatives through the analysis of the derived weights and its underlying decision structure. Ó 2005 Elsevier Ltd. All rights reserved. 1. Introduction There is a growing awareness in our society of the prob- lems concerning contaminated sites that could cause adverse effects on public health and the environment. In Japan, contamination from old industrial sites, uncon- trolled landfills and illegal dumping sites has recently become a major environmental concern. One of the most publicized cases is the Teshima island industrial waste case where the cost was estimated to be more than 30 billion yen (USD 300,000) to rehabilitate the site contaminated with heavy metals, PCBs, dioxins and other toxic substances (Takatsuki, 2003). Moreover, in 2003, Japan’s Ministry of Environment (2004) reported about 2500 contaminated sites were caused by waste management related problem like illegal dumping. Management of such contaminated sites involves deci- sion making efforts which are often complex, multi-dimen- sional, and may involve different stakeholders with different priorities and objectives. For instance, the selec- tion of an appropriate remedial countermeasure would not only be concerned with the technical aspects but also with the social aspects of the problem at hand. This is often a multi-criteria decision problem characterized by interre- lated issues of technological, environmental, economic and societal concerns. Furthermore, such kind of decision making environment involves an ill-defined problem in which behavioral decision research shows that humans are typically quite ineffective at solving, unaided. In this context, decision support tools (DST) such as multi-criteria decision analysis (MCDA) have been recog- nized to play a vital and challenging role in the remediation of contaminated sites (Bardos et al., 2001; Pollard et al., 2004; Linkov et al., 2004). Moreover, the DST can facili- tate communication among decision makers and stake- 0956-053X/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.wasman.2005.11.020 * Corresponding author. Tel.: +81 11 706 7285; fax: +81 11 706 7287. E-mail addresses: mpromentilla@yahoo.com, mabp@kanri-er.eng.ho- kudai.ac.jp (M.A.B. Promentilla). www.elsevier.com/locate/wasman Waste Management 26 (2006) 1410–1421