Phosphorus flow analysis for megacities using a coupled city-hinterland approach: Case study of Beijing. (20th October 2021)

• Record Type: Journal Article
• Authors: Wang, Zihan; Fang, Ke; Lun, Fei; Hartmann, Tobias Edward; Hou, Yong; Zhang, Fusuo; Wu, Jiechen
• Is Part Of: Journal of cleaner production. Volume 320(2021)
• Publication Date: 2021-10-20
• Subjects: Phosphorus flow analysis -- Transboundary flow -- City-hinterland system -- Virtual waste -- Sensitivity analysis -- Policy intervention; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2021.128866
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Rapid urbanization has decoupled phosphorus (P) urban consumption and hinterland production, which has accelerated the need for a broader perspective that includes the city and hinterland in managing the P cycle. However, there is a scarcity of frameworks for the combined city and hinterland approach, aimed at quantifying the transboundary P flow between the city and hinterland. In this study, we developed a coupled city-hinterland framework (using Beijing as a case study) to assess the P flow pattern at the source, waste, and transboundary flow using substance flow analysis, and proposed a pathway to identify the key subsystem in the coupled system by sensitivity analysis. Results shows that the P waste within Beijing is due to human consumption, rather than production, while P waste in the hinterland was nearly twice that observed in Beijing. Further, hinterland crop production subsystems were identified as the key subsystem to reduce P rock demand for the whole coupled system; 39% of P rock demand could be reduced by optimizing fertilizer use in the hinterland. In the scenarios that consider an improvement in technology both in Beijing and its hinterland, 64% and 60% of the total P rock demand and waste were reduced, respectively. Therefore, we provided suggestions to reduce P waste in the coupled system. This study provides a broader perspective to evaluate the impacts of urban consumption on the hinterland, which will serve as a basis for policy decisions for sustainable P flow in the supply chain of other similar cities. Graphical abstract: Image 1 Highlights: Urban P flow and the related P demand from its hinterland were analyzed for Beijing. PUE of Beijing was 50% in 2015, but was only 16%, if the hinterland was included. P waste in Beijing is mainly produced from consumption, rather than production. Transboundary indexes are needed to evaluate the coupled city-hinterland system. Megacities need to establish a coordinated strategy of P management with their hinterland.