Closing the food loops: guidelines and criteria for improving nutrient management

Abstract

As global consumption expands, the world is increasingly facing threats to resource availability and food security. To meet future food demands, agricultural resource efficiency needs to be optimized for both water and nutrients. Policy makers should start to radically rethink nutrient management across the entire food chain. Closing the food loop by recycling nutrients in food waste and excreta is an important way of limiting the use of mineral nutrients, as well as improving national and global food security. This article presents a framework for sustainable nutrient management and discusses the responsibility of four key stakeholder groups-agriculture, the food industry, consumers, and waste management-for achieving an effective food loop. In particular, we suggest a number of criteria, policy actions, and supporting strategies based on a cross-sectoral application of the waste hierarchy.

Manure recycling from urban livestock farms for closing the urban–rural nutrient loops

“…Estimated fertilizer saving for Addis Ababa were in the range of 75 to 300 million Ethiopian Birr (Table 6). Additional benefits relate to replenishing nutrients in crop land and to improving soil quality and nutrient balances (McConville et al 2017;Szogi et al 2015). More difficult to-account-for benefits include reductions in the pollution of soil, surface waters and groundwater, and in the threat of food safety, human health and biodiversity loss (Wen et al 2017).…”

Recycling nutrients contained in human excreta to agriculture: Pathways, processes, and products

“…We recognize that recycling nutrients (and organic matter) from human excreta and streams containing human excreta to food production is only one dimension of establishing a circular nutrient metabolism where nutrients from food are recycled back to the production of food. Establishing such a circular nutrient metabolism requires action along the entire food chain from agriculture and food processing to consumers and Waste Managementement; this includes proper management of harvest residues, animal manure, food processing residuals and waste, and human excreta (McConville et al, 2015). But nutrient recycling is currently constrained by spatial disconnects between livestock intensive areas and areas where feed is produced, and between rural areas where food is produced and urban areas where food is consumed and human excreta produced (Jones et al, 2013;Nesme et al, 2018).…”

“…Growing concern about future fertilizer availability has re-emphasized the need for better nutrient management, including comprehensive recycling of nutrients contained in human excreta to agriculture (Elser & Bennett, 2009;Dawson & Hilton, 2011;McConville et al, 2015). Human excreta have a long history of being used as fertilizer and organic soil amendment but urbanization, the introduction of water closets and sewer networks, and the growing and nowadays widespread use of synthetic fertilizers has contributed to a significant departure from this practice (Rockefeller, 1998;Ferguson, 2014).…”

Extending the European Union Waste Hierarchy to Guide Nutrient-Effective Urban Sanitation toward Global Food Security—Opportunities for Phosphorus Recovery

“…Four interdependent sectors play a vital role: industries, households/ eating places, waste handling agencies, and agriculture (EC, 2012;McConville et al, 2015). The agricultural sector plays an important role as a recipient of urban nutrients and provider of food products but is not analyzed here in its own right, as the focus is on urban nutrient flows.…”

“…The extended waste hierarchy and life cycle thinking serve the dual purpose to enhance sustainability of nutrient resources and to improve global food security. Applying the hierarchy in this way can assist stakeholders to identify wasteful handling of nutrients in urban waste and to suggest measures to better manage those nutrients (McConville et al, 2015).…”