Introduction

Circular economy includes three subsectors: liquid waste, solid waste, and wastewater treatment. These three sectors are derived from volume 5 of the IPCC guidance for national greenhouse gas inventories and include detailed emissions estimates from wastewater treatment and management pathways, solid waste treatment pathways (including a first-order decay model of landfilled waste), and recycling, which then gets passed to the industrial production model to estimate changes for producing virgin materials. Waste generation primarily is driven by per-person generation factors, which are responsive to changes in GDP, GDP/capita, and population and other sectors, including livestock manure management and supply-chain loss in agriculture.