Environmental sustainability analysis of dairy bedding regeneration system based on emergy evaluation and life cycle assessment methods

Dairy farm bedding can be produced by composting technology using dairy manure, which offers advantages in terms of cost, availability, and economic value. However, few information is available on the environmental sustainability and impacts for manure recycling systems based on different composting methods. The resource-environmental impact and eco-economic sustainability of two manure bedding regeneration systems: forced-ventilation static-stack aerobic fermentation (FVSSAF) system (Scenario A) and bedding recovery unit (BRU) system (Scenario B) were evaluated in this study. The life cycle assessment yielded a combined environmental impact potential of 0.01032 for scenario B, much lower than the 0.02656 for scenario A. The emergy evaluation showed that scenario B can handle more dairy manure than scenario A due to 57% increase of emergy input. Form the emergy indices of the two systems, scenario B had lighter environmental pressure and higher sustainability. Therefore, the BRU system had economic advantages and ecological sustainability, which was more suitable for large dairy farms. The trade-offs between environmental consequences, resource efficiency, and economic benefits were analyzed from several perspectives in this study, which would help stakeholders to have a new understanding when choosing a bedding recycling system.