Chapter 11 - Principles of Environmental Sciences: Solid and Hazardous Waste
Principles of Environmental Sciences
Solid and Hazardous Waste
Instructor: Dr. Abir Hamze
Institution: Canadian University of Dubai
Solid Waste Management
Definition of Solid Waste
Solid Wastes:
Refers to the wastes that arise from human activities.
Typically solid as opposed to liquid or gaseous waste.
Discarded as useless or unwanted materials.
Issues Related to Improper Disposal of Waste
Environmental Problems:
Pollution
Diseases
Odors
Impact on Animals
Fire Hazards
Objectives of Solid Waste Management
Key Objectives
Reduce the quantity of solid waste disposed of on land.
Recovery of materials and energy from solid waste.
Efficient Integrated Solid Waste Management (ISWM)
Definition:
An efficient ISWM system considers strategies to reduce, reuse, recycle, and otherwise manage waste, aiming to protect both human health and the environment.
National Strategy:
ISWM is a national strategy comprising the selection and application of appropriate techniques, technologies, and management programs for solid waste management.
Goals:
To minimize waste generation.
To maximize reuse, recycling, and material recovery.
To recover energy.
To dispose of remaining waste in landfills.
Elements of Solid Waste Management
Waste Management Process Steps
Waste Generation:
The initial creation of waste.
On-site Handling, Sorting, Storage, and Processing:
Managing waste where it is generated.
Collection:
Gathering waste for further processing.
Sorting, Processing, and Transformation:
Preparing waste for recycling or disposal.
Transfer and Transport:
Transporting waste to processing or disposal sites.
Key Components:
Transfer from small vehicles to larger transport equipment.
Often involves long-distance transport.
Disposal:
Final disposal in landfills or incineration.
Solid Waste Management Hierarchy
Treatment Options
Waste Treatment and Disposal Methods:
Source Reduction:
Reuse:
Recycling:
Resource Recovery:
Incineration:
Landfilling:
Objectives:
Arrange methods in order of preference based on environmental impact.
Types of Solid Wastes
Classification
Major Categories
Municipal Solid Waste (MSW):
Non-hazardous solid waste from cities or towns.
Hazardous Wastes (HW):
Harmful to human health and the environment.
Industrial Wastes:
Generated from manufacturing processes.
Agricultural Solid Wastes:
Includes crop and animal waste.
Special Wastes:
Includes specific products like batteries, electronics, etc.
Sources of Municipal Solid Wastes (MSW)
Residential:
Waste generated in homes.
Commercial:
Includes waste from stores, restaurants, offices.
Institutional:
Waste from schools, hospitals, government centers.
Construction and Demolition:
Waste from construction sites and renovation projects.
Municipal Services:
Waste associated with landscaping and park maintenance.
Hazardous Wastes (HW)
Characteristics
Toxic:
Poisonous in small amounts (e.g., heavy metals, pesticides).
Reactive:
Can react violently with air or water (risk of explosion).
Ignitable:
Burns at low temperatures (e.g., gasoline).
Corrosive:
Destroys materials through chemical reactions (e.g., acids).
Classification:
Hazardous wastes are classified based on the presence of one or more of these characteristics.
Definitions of Waste Types
Refuse
Definition:
All non-hazardous solid waste requiring collection for transport to a processing/disposal site.
Includes:
Garbage:
Decomposable food waste (fruits, vegetables, etc.).
Rubbish:
Dry material (glass, paper, wood).
Special Wastes
Bulky Items:
Includes furniture and large appliances.
Household Hazardous Waste:
Paint, cleaners, and batteries.
Agricultural Solid Wastes:
Includes crops and livestock waste.
Recycling and Recovery of Materials
Municipal Solid Waste Recovery
Materials Typically Recovered:
Aluminum, paper, cardboard, plastics, glass, metals, aseptic materials.
Solid Waste Management Techniques
Composting
Process:
A biological process allowing organic waste to decompose in controlled conditions.
Volume Reduction:
Can reduce waste volume by up to 50%.
Incineration
Definition:
A method of waste treatment that reduces volume and weight through burning in a furnace at high temperatures.
Systems Involved:
Usually includes cranes, furnaces, turbines, and smokestacks for energy generation.
Components:
Waste pit, scrubbers, and ash treatment systems.
Landfills and Waste Disposal
Sanitary Landfills
Definition:
Engineered facilities where solid waste is compacted and covered with layers of soil or clay.
Safety Measures:
Includes leachate monitoring and methane recovery systems.
Leachate Management
Components:
Pipes to collect leachate (runoff) for treatment.
Protection Measures:
Clay and plastic lining to prevent leakages into groundwater, with monitoring wells for leak detection.
Hazardous Waste Management
Options for Management
Eliminate or Reduce:
Reduce waste quantities at the source.
Reclaim and Recycle:
Recycle waste for reuse in industrial processes.
Stabilize Waste:
Render waste nonhazardous chemically or biologically.
Incineration:
High-temperature destruction or detoxification.
Modern Land Disposal:
Application of advanced landfill methods.
Secure Landfills for Hazardous Waste
Design Features:
Minimum height separation from bedrock, double-liner systems, collection systems for leachate, and monitoring wells.
Deep-Well Injection Disposal
Overview of Method
Advantages:
Safe if locations are carefully chosen, low cost, and easy execution.
Disadvantages:
Risk of leaks due to corrosion, natural fractures, or seismic activity.
Types of Injection Wells
Classifications:
Class I: Industrial waste.
Class II: Oil and gas-related waste.
Class III: Uranium mining and disposal.
Conclusion
Understanding solid and hazardous waste management is crucial for environmental protection and health. Practicing sustainable waste management techniques can mitigate negative impacts associated with waste disposal and enhance resource recovery.