Landfill Closing: an Economic Assessment of Environmental Benefits

The increasing public attention to solid waste management points out the importance of studying and evaluating alternative options to reduce the total quality of waste going to final disposal. In particular, the US Management Act (1998) and the European Landfill Directive (1999) focus on the negative effects derived from landfilling of waste. In fact, many environmental impacts (external effects) due to landfilling can be associated to land use, landfill gas, disamenity, leachate and risk of accidents. The evaluation of these impacts is complex and many economic methods have been proposed in the last decades. This chapter has s twofold aim: first we would describe pros and cons of economic methods available to estimate landfill effects by reviewing the economic literature on landfill evaluation, second we would put in evidence some interesting results of a contingent valuation study applied to the landfills closing in the Province of Siena (Italy). In particular, we introduce dichotomous choice question in a double-bounded referendum format, critically analysing data for strategic behaviour in the answer process. Crucially, we compare different econometric models with the aim to choose the most efficient and unbiased one. Results suggest that the distribution of underlying preferences implied by answers to the initial question referendum question is not the same as that implied by the entire sequence of replies. Since the strategic behaviour can influence the follow-up responses, we finally define conditions to obtain unbiased and efficient welfare measures in evaluating benefits due to landfill closing