Environmental Chemistry Part V: Environment and the Solid State

General Overview

• Focuses on environmental implications of solid-state chemistry, including:
  • Soil composition and chemistry.
  • Sediments in aquatic systems.
  • Waste generation, disposal, and remediation.
• Covers waste types: domestic garbage, hazardous materials, and industrial waste.
• Highlights modern landfill technologies, recycling methods, and the environmental impact of solid waste.

Chapter 16: Wastes, Soils, and Sediments

Introduction

• Discuss the progression from low-to-high toxicity materials:
  • Domestic garbage and minimization.
  • Soil and sediment contamination.
  • High-tech hazardous waste disposal.

16.1 Domestic Garbage: Composition and Minimization

• Key Statistics
  • Average North American generates ~2 kg of waste daily.
  • Waste breakdown by type and economic development level (vegetable matter, paper, plastics).
• Minimization Strategies
  • Encouraging recycling.
  • Composting to reduce organic matter in landfills.

16.2 Landfills: Structure and Function

• Modern Landfill Design
  • Use of clay caps, geomembranes, and leachate collection systems to prevent contamination.
  • Methane gas collection for energy use.
• Stages of Decomposition
  • Aerobic (oxidation of organics).
  • Acidic fermentation (organic acid production).
  • Methanogenic (methane and CO₂ generation).

16.3 Incineration of Garbage

• Advantages
  • Reduces waste volume.
  • Generates energy from organic components.
• Concerns
  • Emissions (dioxins, furans, particulates).
  • Toxicity of fly ash.

16.4 Recycling

• Recycling Principles
  • The Four R's: Reduce, Reuse, Recycle, Recover.
  • Focus on metals, paper, plastics, and glass.
• Challenges
  • Economic viability for non-metal recycling.
  • High energy use in some recycling processes.
• Success Stories
  • Aluminum: Saves 95% of energy vs. virgin production.
  • E-waste recovery: Recycling valuable metals like copper, aluminum, and steel.

16.5 Green Chemistry Innovations

• Bio-based toner to simplify recycling.
• Eco-friendly carpet recycling using nylon-6 fibers and polyolefin backings.

Soils and Sediments

• Soil Composition
  • Components: Inorganic minerals, organic matter, water, and air.
  • Role of clay particles in ion exchange and nutrient retention.
• Sediments
  • Interaction with pollutants.
  • Processes of adsorption and chemical binding in aquatic systems.

Teaching Suggestions

• Visual Aids: Diagrams of landfill designs, recycling processes, and soil particle interactions.
• Case Studies: Real-world examples of landfill failures and innovative recycling programs.
• Interactive Assignments:
  • Calculate methane emissions from a landfill.
  • Compare recycling energy use between different materials.
• Class Discussions: Debate on the effectiveness of recycling policies in industrialized vs. developing nations.