气候变化领域集成服务门户

Livestock waste may cause air quality degradation from ammonia and methane emissions, soil quality detriment from the in-excess nutrients and acidification, and water pollution issues from nutrient and pathogens runoff to the water bodies, leading to eutrophication, algal blooms, and hypoxia. Despite the significant environmental benefits of performing pollution management for these organic materials, the recovery of value-added products from livestock waste is not a current practice due to the high investment costs required and the low market values being offered for the recovered products. In addition, the deployment of waste treatment technologies is hindered by the difficulty to attribute an economic value to environmental benefits. We present a supply chain design framework to conduct simultaneous economic and environmental analysis of post-livestock organic material to value-added products. The proposed framework captures techno-economic and logistical issues and can accommodate diverse types of policy incentives obtained at federal and state levels, allowing stakeholders to conduct systematic studies on the effect of incentives on the economic and environmental viability of diverse technologies. We apply the framework to a case study for dairy farms in the state of Wisconsin (U.S.), where we consider the placement of anaerobic digestion in combination with nutrient recovery and biogas upgrading technologies. The framework reveals that, from a purely economic perspective, products recovered from dairy waste are not competitive at current market prices. We also find that incorporating current and potential U.S. government incentives in the form of Renewable Identification Numbers (RINs) and phosphorus credits can achieve economic viability of the recovery of liquefied biomethane and nutrient-rich products. On the other hand, adding current incentives for electricity generation (Renewable Energy Credits or RECs), the system cannot achieve economic viability. The analysis also reveals that the best strategy to manage waste is to deploy technologies that conduct simultaneous recovery of liquefied biomethane and nutrients.