Dairy and swine manure management-Challenges and perspectives for sustainable treatment technology

Global dairy and swine production growth has increased significantly over the past decades, resulting in higher ma-nure generation in certain areas and environmental concerns. Therefore, manure management is an essential focus for farmers and environmental regulators. Systematic selection of manure management practices can provide envi-ronmental benefits, but accounting for local constraints, economics and farming practices are significant challenges. All these factors drive the selection of appropriate manure management systems (MMSs). MMSs are highly varied for their design, partly due to individual farm settings, geography, and the end-use applications of manure. However, the benefits of technological advancements in MMSs provide higher manure treatment efficiency and co-production of value-added products such as recycled water, fiber, sand bedding, and nutrient-rich bio-solids, among others. To achieve higher environmental benefits, advanced manure treatment technologies have to be implemented, which comes with additional costs. So, there is a tradeoff between environmental benefits and cost. With the above pros-pects, this article reviews: 1) the different treatment technologies used in dairy and swine farms, 2) the life cycle as-sessment (LCA) method's importance in evaluating various treatment technologies for better environmental returns, and 3) decision support tools (DST) and their significance in MMSs prioritization. We found considerable heterogeneity in the available datasets, mainly on crucial parameters such as water consumption, types and amount of bedding materials, manure removal frequency, manure treatment technologies, and the extent of resource recov-ery. Thus, suitable environmental impact assessment inventory models are needed to evaluate a more comprehen-sive range of treatment technologies in MMSs, representing the spatial and farming system heterogeneities. There is also a need for user-friendly DST with adjustable inputs for the functional components of MMSs and evaluation criteria, which can rapidly evaluate the techno-economic feasibility of alternative systems. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Global growth in dairy and swine production has led to increased manure generation, necessitating a focus on manure management for environmental reasons. The diversification of manure management systems is driven by individual farm settings, geography, and end-use applications, leading to a tradeoff between environmental benefits and costs. Technological advancements offer opportunities for higher manure treatment efficiency and the co-production of value-added products, but the implementation of advanced technologies comes with additional costs.