Identifying sustainable options for rice husk valorization using the analytic hierarchy process

Abstract

Rice husk is a major waste of paddy rice cultivation, produced in very high quantities, with no specific applications in the past. However, considering physical and chemical properties of this material, the use of rice husk could be of major economic and environmental significance depending on possible utilization options. Therefore, finding sustainable ways of using rice husk is essential for a large rice producing country like Iran. The main aim of the present study was to identify the most suitable options for using rice husk to accomplish the goals of sustainable rice production and valorization in Guilan Province, Iran. To this end, we employed the analytic hierarchy process and the opinions of experts for exploring the most important potential applications of rice husk for industrial purposes, for energy generation, use as animal feed, for soil improvement, for mulching, and disposal by burning from economic, environmental, and social perspective. Among the studied indices, the economic criteria had the highest importance score (0.498) in determining the best applications of rice husk, followed by environmental and social indices (0.276 and 0.225, respectively). From the economic perspective, the use of rice husk waste for industrial purposes (0.349) was assessed to be more economical than use in other sectors. From the environmental perspective, rice husk was preferred to be used for soil improvement. Finally, from the social perspective, the use of rice husk for industrial use (0.315) was also assessed to be more socially compatible than its other uses. Overall, the application of rice husk in industry was prioritized by respondents with weight 0.299, with next priority its use for energy generation or processing with weight 0.188, showing a slight superiority over its application for soil amendment. The findings not only aid in selecting the best alternative for husk exploitation but also help decision makers to understand why an alternative is preferred over the other options.