Toward a Circular Economy Approach for Integrated Intensive Livestock and Cropping Systems

Abstract

The separation between cropping systems and livestock has caused an imbalance in the nutrients, increasing the environmental impact of both industries. In this work, an integrated system comprising intensive livestock and crop management is compared with traditional systems, from the economic and environmental points of view. A model for estimating energy and nutritional requirements of beef cattle, a waste treatment process, a nutrient recovery system, and crop management is integrated into a mathematical optimization framework. This integrated model allows relating the formulation of the feed of the animals with the composition of their feces, the necessary cultivation area, the crops, and the fertilizers required as well as carrying out the economic and environmental evaluation of the entire system, balancing the nutrients between both industries. Through the application of the model to a representative case study with 1000 animals, a 62% reduction in the environmental impact of the combined agricultural system has been achieved, with a 14% decrease in the profit compared to the nonintegrated system. The fertilizer formulation is optimized to add exactly the required amount of each nutrient to reduce nutrient pollution. 30% of the nitrogen and 56% of the potassium needed for the crops can be obtained from the livestock waste. The correct formulation of the feed can reduce the amount of phosphorus in the feces down to 0.01%. The results show that the integrated system makes it possible to significantly reduce the environmental impact, but it is still not economically promising yet.

Optimal Integrated Plant for Biodegradable Polymer Production

“…A fraction of the digestate produced after anaerobic digestion is sent to the ponds as nutrients for algae growth, while the rest is processed to extract the nutrients for fertilizer production. 31 Biogas Reforming. The reforming of biogas is intended to produce syngas via dry or hybrid reforming with steam.…”

“…A fraction of the digestate produced after anaerobic digestion is sent to the ponds as nutrients for algae growth, while the rest is processed to extract the nutrients for fertilizer production. 31 …”

Addressing the contribution of agricultural systems to the phosphorus pollution challenge: a multi-dimensional perspective

“…These models can be used to formulate multi-objective optimization frameworks for the conceptual design of integrated agricultural systems for different objective scenarios such as the maximization of the economic profit of the system, the minimization of the environmental impacts of the system (including the global warming potential, eutrophication potential and the water footprint), or the search of the trade-off solutions between the profitability of the system and the reduction of its environmental impacts, reducing the external supply of phosphorus and the emissions of greenhouse gases (Taifouris and Martin, 2021).…”

Integrating intensive livestock and cropping systems: Sustainable design and location

“…These correlations, yields, and mass balances have also been included in the supplementary material. The food that is not used as animal feed is sold as a by-product (only barley and wheat since the rest of the crops are either fully fed or have no market value (Taifouris and Martin, 2021)). In addition, the manure is treated to produce biogas and digestate through an anaerobic digestion system.…”

“…Therefore, intensive farming is necessary to supply food in an economically sustainable way to a growing population. Authors, such as Taifouris and Martin (2021) have addressed this type of integration for intensive livestock farming. Through models for estimating energy and nutritional requirements, waste treatment, nutrient recovery, and crop management, it is possible to determine the optimal feed formulation for the animals, the required crops, as well as the operating conditions of the waste treatment process, and the optimal formulation of fertilizers.…”