The application portfolio empowerment method and ELECTRE-I for optimising the control of ammonia release during the aerobic fermentation process.

Aerobic fermentation composting can transform solid organic waste into biological organic fertiliser, while reducing resource wastage and ecological damage. However, in the composting process, a serious loss of nitrogen occurs, primarily in the form of the release of ammonia gas. The release of ammonia gas not only pollutes the environment, but also diminishes the presence of nutrient elements, resulting in compost products that are lower in quality. Given that many factors influence the release of ammonia gas during the aerobic fermentation process, it is difficult to determine optimal process parameters. In an effort to address this issue, we propose herein a combinational weighting method based on the analytic hierarchy process (AHP) and entropy weighting method to determine the weight of each secondary index. We also establish a parametric optimisation model based on the ammonia release conditions of the ELECTRE-I method that provides a theoretical underpinning and a decision basis for optimising the process parameters that mediate the release of ammonia during the aerobic fermentation process. This method can be widely employed to reduce the release of ammonia gas and may be of significance to the future development of bioengineering-based composting technology.