Environmental Management Lecture 11: Waste Management

Environmental Management - Lecture 11: Solid Waste Management

• Solid waste is a resource in the wrong place at the wrong time. Proper use can make it a valuable resource.

• Jane Jacobs predicted urban waste could be a future gold mine.

• Poerbo (1991) highlights the importance of balancing health, environmental, and economic aspects of waste management.

• Global waste generation is projected to increase substantially by 2030 and 2050. North America, Latin America and the Caribbean, Middle East & North Africa, Sub-Saharan Africa, South Asia, and Europe and Central Asia show significant regional variations in waste generation. (Data shown in millions of US tons)

• The transition to disposable containers started before WWII and was finalized in the 1980s, beginning with soda/beer containers, extending to razors, diapers, pens, and cigarette lighters by the 1970s.

• In the past, milk, soda, and beer bottles were regularly returned and re-used.

• Grocery stores used brown paper bags that could be reused creatively, such as for school book covers. Babies’ diapers were washed. Clothes were dried on lines rather than energy-intensive machines.

• Fragile items were packaged with old newspapers, water was collected from fountains instead of plastic bottles, writing pens were refilled, and razor blades were replaced.

Types of Waste

• Liquid Waste: Waste in non-solid forms; includes storm water, wastewater, wash water from homes, industrial cleaning liquids, and waste detergents. Some solid waste can be converted to liquid waste for disposal.

• Solid Waste: Garbage and refuse, sludge from water/wastewater treatment plants and air pollution facilities, discarded materials (solid, liquid, semi-solid, or gaseous) from industrial, commercial, mining, agricultural and community activities. Hazardous or non-hazardous.

Municipal Solid Waste Source

• Municipal solid waste comes from residential, commercial, institutional and industrial sources.
  • Types include plastic, glass, metal, and tires

Composition of Municipal Solid Waste

• Municipal Solid Waste (MSW) contains varying percentages of materials:
  • Paper and paperboard (27%)
  • Yard trimmings (14%)
  • Food waste (13%)
  • Plastics (13%)
  • Metals (9%)
  • Rubber, leather and textiles (9%)
  • Wood (6%)
  • Glass (5%)

Solid Waste Characteristics

• Physical and chemical composition of solid waste varies depending on the sources.

• Landfill waste characteristics affect gas and leachate production and composition, factors such as degradable vs nondegradable components, moisture content, and the bio-degradable element.

• Waste composition impacts both bulk gases and trace components.

• Solid waste is complex multiphase mixtures whose composition analysis is not easy.

• Random sampling techniques are often used for determining composition.

• Waste is reduced to ~100 kg using standard coning and quartering procedures for analysis.

Waste Characteristics - Physical and Chemical

• Physical characteristics include density, moisture content, size distribution of components, color voids, shape of components, particle size, optical and magnetic properties, field capacity, and compacted waste porosity.

• Chemical characteristics include moisture content (water content), volatile matter, fixed carbon, fusing point of ash, calorific value (energy content), oxygen, sulphur and ash percentage.

Waste Characteristics - Biological

• The primary biological characteristic of MSW's organic fraction is its biodegradability (convert to gases and inert solids).
• Odors and fly breeding relate to the putrescible nature of organic materials like food waste.

Types of Waste - Hazardous

• Hazardous waste includes harmful or potentially harmful materials. This includes waste that is flammable, reactive, corrosive, and/or toxic. Examples include fire extinguishers, old propane tanks, pesticides, mercury containing equipment, thermostats, lamps (fluorescent bulbs) and batteries.

Types of Waste - Organic

• Organic waste comes from plants and animals. This typically includes food waste, fruit and vegetable peels, flower trimmings, and animal waste (e.g., dog poop).
• Organic waste is biodegradable.
• Many people compost organic waste for use in gardens.

Types of Waste - Recyclable

• Recyclable waste can be reprocessed into new materials. Examples include aluminum products, plastic materials, glass, paper products, and cardboard boxes.

Sources of Waste

• Municipal: Trash from households, schools, offices, markets, restaurants, and other public places (food waste, plastic bags, soda cans, plastic water bottles, broken furniture, grass clippings, packaging, broken appliances, and clothing)

• Medical/Clinical: Waste from healthcare facilities—hospitals, clinics, surgical theatres, veterinary hospitals, and labs (surgical items, pharmaceuticals, blood, body parts, wound dressing, needles, and syringes)

  • Different materials of waste have specific waste disposal procedures, for example, soilled anatomical and chemical liquid/cytotoxic waste.
  • Different waste sources are separated to appropriate disposal procedures.

• Agricultural: Waste generated by agriculture, including empty pesticide containers, old silage wrap, out-of-date medicines/wormers, used tires, surplus milk, cocoa pods, and corn husks.

• End-of-life automobiles: Old and broken cars, trucks, buses and rickshaws.

• Industrial: Waste created by industrial processes and production—glass, leather, textiles, food, electronics, plastics, and metals.

• Construction/Demolition: Waste from road and building construction and demolition, including concrete debris, wood, earth, large boxes, and plastics from building materials

• Electronic: Waste from electronic devices, also known as e-waste (TVs, computers, electronics). Contains lead, mercury, cadmium, and brominated flame retardants.

Effects of Waste & Poor Waste Disposal

• Environmental: Surface water, soil contamination
• Economic: Reduced municipal wellbeing (poor sanitation, lack of hygiene, negative impact from poor waste disposal) and decreased recycling revenue (lack of appropriate waste management systems = reduction in jobs, recycling, and composting operations)
• Social/Public Health: Pollution resulting from bad waste management can cause adverse respiratory problems and other health concerns as contaminants get absorbed into the body. Leachate (liquid from contaminated areas) is harmful; it is a mixture of chemicals that can lead to contamination of surface water, ground water, or soil.