Assessing the effectiveness of municipal solid waste segregation at source on landfill emissions and greenhouse gas mitigation in urban areas

Project Abstract

This study assesses how source-separated municipal solid waste (MSW) streams influence landfill emissions and greenhouse gas (GHG) mitigation in urban areas, with a focus on practical implementation, dynamics of behavior change, and system-level environmental outcomes. The research employs a mixed-methods design combining quantitative analysis of waste composition, diversion rates, and GHG inventories with qualitative insights from stakeholders, including municipal authorities, waste management firms, and residents. Data were collected across multiple urban municipalities implementing varying levels of source separation programs, complemented by life cycle assessment (LCA) and emission modeling to quantify methane (CH4) and nitrous oxide (N2O) fluxes from landfills under different waste sorting scenarios. The study also investigates the energy and resource implications of increased recycling and composting yields, evaluating trade-offs between collection logistics, contamination rates, and processing capacities. A central objective is to quantify the margin of GHG reductions achievable through source separation and identify the key levers that maximize benefits while minimizing unintended consequences such as increased emissions from extended collection networks or anaerobic processing delays. The research develops and calibrates a regional emission accounting framework that integrates material flow analysis (MFA) with landfill gas collection efficiency, landfill cover technologies, and post-closure methane oxidation potential. Results indicate that high-quality source-separated streams substantially reduce landfilled organic waste fractions, leading to lower methane generation potential and improved biogas capture efficiency. However, the magnitude of GHG mitigation is highly sensitive to contamination rates, diversion-to-energy ratios, and the performance of downstream facilities. The study reveals that commingled or poorly sorted waste streams, despite modest improvements in diversion, may result in higher overall GHG emissions when lax collection routes increase fuel consumption and hinder methane capture. Policy scenarios simulated include extended producer responsibility, incentivized pay-as-you-throw schemes, and investment in decentralized composting and anaerobic digestion (AD) facilities. Economic analysis demonstrates the cost-effectiveness of source separation in relation to avoided GHG damages, considering regional carbon prices, capital expenditure, and operational costs. The social dimension explores resident compliance, public awareness campaigns, and equity implications of MSW programs, highlighting how behavior change mediates environmental outcomes. The study culminates in a decision-support framework for urban policymakers, outlining best-practice thresholds for contamination limits, target diversion rates, and infrastructure readiness to maximize GHG mitigation while maintaining system resilience. Limitations include variability in climate, waste composition, and governance structures across study sites, as well as uncertainties in methane capture performance and post-closure emissions. The findings contribute to advancing standardized methodologies for measuring the climate impact of source-separated waste management and offer actionable guidance for scaling up effective MSW segregation practices to achieve meaningful urban-scale GHG reductions.

Project Overview

What This Project Is About

---

A plain-language overview of the topic and what the project investigates.

---

---

The Problem It Addresses

---

What problem or gap this project tackles and why it matters to the field or society.

---

---

Objectives of the Project

---

1. Identify how separating waste at the source affects landfill emissions.
2. Quantify the reduction in greenhouse gases from improved waste segregation.
3. Compare urban areas with and without source-separation programs.
4. Suggest practical improvements for municipal waste policies.

---

---

What You Will Do Step by Step

---

1. Review existing literature on waste segregation and methane/CO2 emissions.
2. Map current waste streams in a selected city and determine segregation levels.
3. Collect data on landfill gas emissions and composition for different scenarios.
4. Analyze how changes in segregation could lower emissions using simple models.
5. Assess social and logistical factors that affect implementation.

---

---

Expected Outcome

Answers to whether source-segregated waste lowers emissions and how much, plus practical guidelines for cities to adopt or improve programs.