عنوان مقاله [English]
In the absence of adequate applied environmental studies, this research estimated a stochastic normalized output distance function, using econo-metric stochastic frontier analysis (SFA), for livestock slaughterhouses. The production data for 2003 was collected and the environmental pollution parameters (biochemical, chemical and microbial pollution) were measured by analyzing the wastewater samples from entry and egress channels of effluent treatment systems in all livestock slaughterhouses located in Tehran province. The environmental and resource use efficiencies were also estimated and compared between different groups of slaughterhouses. The effectiveness of treatment systems in improving the environmental performance was determined by statistical tests. The results revealed that most firms were inefficient as their environmental and resource use efficiencies were 57.74 and 52.75, respectively. However, the improvement of the environmental performance was possible with current technologies. The efficiencies showed better status for mechanized and non-public firms and those using biological systems as compared to public and traditional ones. Finally, suggestions were given in order to improve the environmental efficiency. This approach was suggested to environmental planners and policymakers as an applied and scientific basis for evaluating the environmental performance of firms.