The Method of the WFD

The Waste Flow Diagram estimates its data by referring to user’s data collection, e.g., in form of observations, and a Material Flow Analysis (MFA) approach.

How does the assessment work?

The Waste Flow Diagram has been developed to provide a rapid assessment method for low and middle income communities or cities to understand their waste management systems.

Therefore, material flow analysis is used to assess and map waste flows throughout the waste management system.

Flows represent possible material pathways, quantified in tonnes per year.

Important aspects such as contributions from the informal waste sector are also quantified.

A unique observational approach provides a quick estimate of plastic leakage and identification of problem areas. This is achieved using decision trees and descriptive tables for each part of the waste management system, which incorporate waste management infrastructure and practices into the calculation of leakage potential. The total plastic leakage from the waste management system is calculated as the sum of plastic leakage from each stage by multiplying the leakage percentages by the total amount of plastic flowing through the system at each specific MSWM stage.

The results of the Waste Flow Diagram are presented in either a material flow diagram for in-depth analysis or simpler Sankey diagrams for communication and dissemination. In addition, the plastic pollution results are converted into easily understood values such as “PET bottles per person per year” or “number of waste trucks per year” to enable all stakeholders to understand the significance of the results.

Built-in scenario capabilities allow the user to understand the potential impact of applying interventions within the waste management system. For example, the user can simulate how increasing collection coverage by a certain amount would affect the rest of the waste management system, including the amount of plastic leaking into water. Transparent and clear results also provide benchmarking opportunities for cities to track their progress.

Interoperable with SDG 11.6.1

The WFD is specifically created to integrate with the SDG 11.6.1 methodology, users of the Waste Flow Diagram will be guided through the process of data collection in area lacking such information. Results will further inform the SDG 11.6.1 sub-indicators, providing benchmarking capabilities and visualisation of results.

SDG 11.6.1 – Proportion of municipal solid waste collected and managed in controlled facilities out of total municipal solid waste generated by cities

WFD Overview Diagram

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Waste Flow Diagram