Wastes and Their Management

Lecture 11: Wastes and Their Management

What are Wastes?

• Waste is unwanted or useless materials.
• In biology, waste is any of the many unwanted substances or toxins expelled from living organisms.
• Basel Convention Definition: "substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of the law"
• Disposal: any operation which may lead to resource recovery, recycling, direct re-use, or alternative uses.

Basel Convention

• International treaty designed to reduce the movements of hazardous waste between nations.
• Aims to prevent the transfer of hazardous waste from developed to less developed countries (LDCs).
• Does NOT address the movement of radioactive waste.

Kinds of Wastes

• Solid wastes: wastes in solid forms, including domestic, commercial, and industrial wastes.
  • Examples: plastics, containers, bottles, cans, papers, and other trash.
• Liquid Wastes: wastes in liquid form
  • Examples: domestic washings, chemicals, oils, and wastewater.

Solid Waste (EPA Definition)

• Any garbage or refuse (Municipal Solid Waste).
• Sludge from a wastewater treatment plant.
• Material from industrial, commercial, mining, and agricultural operations, and from community activities.

Classification of Wastes According to Properties

• Bio-degradable: can be degraded (e.g., paper, wood, fruits).
• Non-biodegradable: cannot be degraded (e.g., plastics, bottles, old machines, cans).

Classification of Wastes According to Effects on Health and Environment

• Hazardous wastes: unsafe substances with properties like ignitability, corrosivity, reactivity, & toxicity.
• Non-hazardous wastes: safe substances that do not have the hazardous properties mentioned above.

Classification of Wastes According to Origin and Type

• Municipal Solid Wastes: household garbage, rubbish, construction & demolition debris, packaging materials, etc., managed by a municipality.
• Bio-medical Wastes: Solid or liquid wastes generated during diagnosis, treatment & research activities of medical sciences, including containers, intermediate or end products.
• Industrial Wastes: Liquid and solid wastes generated by manufacturing & processing units (e.g., chemical, petroleum, coal, metal, gas, paper).
• Agricultural Wastes: Wastes generated from farming activities.
• Fishery Wastes: Wastes generated due to fishery activities, commonly found in coastal areas.
• Radioactive Wastes: Waste containing radioactive materials, usually byproducts of nuclear processes.
• E-wastes: Electronic wastes generated from modern establishments (discarded electrical or electronic devices).
  • Some electronic scrap components may contain contaminants such as Pb, Cd, or organobromine compounds.

Waste Hierarchy (Most to Least Favored)

• Prevention
• Minimisation
• Reuse
• Recycling
• Energy Recovery
• Disposal

Waste Minimization

• Minimizing solid waste by:
  • Minimizing packaging.
  • Using recyclable materials: paper, plastics, metals, glass, wood.
  • Using reusable materials: leather, rubber, metals, wood.
  • Composting: yard trimmings, food scraps (vegetable).

Waste: Municipal Compost

• Food waste and green waste from gardens mixed with a small quantity of compost activator (contains micro-organisms and enzymes to promote efficient composting).

Categories of Waste Disposal

• Dilute and Disperse (Attenuation):
  • Throwing waste in the river/lake/sea.
  • Burning it.
• Concentrate and Contain (Isolation):
  • Waste dumps, landfills. (Historically, that's how most of the solid waste gets treated).

Useful Options for Waste Management

• Biomethanation: A process by which organic material is microbiologically converted under anaerobic conditions to biogas.
• Energy recovery.
• Incineration.
• Resource recovery.
• Composting.

Sources of Human Exposures

• Ingestion of contaminated water or food.
• Contact with disease vectors.
• Inhalation.
• Dermal.

Points of Contact

• Soil adsorption
• Storage
• Plant uptake
• Ventilation
• Runoff
• Leaching
• Insects, birds, rats, flies, and animals.
• Direct dumping of untreated waste in seas, rivers, and lakes affects the plants and animals that feed on.

Impacts of Waste if Not Managed Wisely

• Affects our health
• Affects our socio-economic conditions
• Affects our coastal and marine environment
• Affects our climate

Impacts of Waste on Climate

• Green House Gases are accumulating in Earth’s atmosphere because of human activities.
• This causes global mean surface air temperature and subsurface ocean temperature to rise.
• Rising global temperatures are expected to raise sea levels and change precipitation.
• Changing regional climates could alter forests, crop yields, and water supplies.
• This could also affect human health, animals, and ecosystems.

Activities Altering Chemical Composition of the Atmosphere

• Buildup of GHGs primarily:
  • carbon dioxide ($CO_2$)
  • methane ($CH_4$)
  • nitrogen dioxide ($NO_2$).
• $CO_2$ is released by burning fossil fuels, wood and wood products, and solid waste.
• $CH_4$ is emitted from the decomposition of organic wastes in landfills, the raising of livestock, and the production of coal, natural gas, and oil.
• $NO_2$ is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels.

Impacts of Waste on Health

• Chemical poisoning through chemical inhalation.
• Uncollected waste can obstruct storm water runoff, resulting in floods.
• Low birth weight.
• Cancer.
• Congenital malformations.
• Neurological disease.
• Nausea and vomiting.
• Increase in hospitalization of residents living near hazard waste sites.
• Mercury toxicity from eating fish with high levels of mercury.

Effects of Waste on Animals and Aquatic Life

• Increase in mercury level in fish due to disposal of mercury in the rivers.
• Plastic found in oceans ingested by birds.
• Resulted in high algal population in rivers and sea.
• Degrades water and soil quality.

Impacts of Waste on Environment

• Waste breaks down in landfills to form methane, a potent greenhouse gas.
• Change in climate.
• Destruction of ozone layer.
• Leaching: a process by which solid waste enters soil and groundwater and contaminating them (U.S. Environment Protection Agency).
• Food wasted by the US and Europe could feed the world three times over.
• Food waste contributes to contamination of freshwater along with methane and $CO_2$ emissions from decomposing food, impacts global climate change.
• Every ton of food waste prevented has the potential to save 4.2 tons of $CO_2$ equivalent.
• If we all stop wasting food that could have been eaten, the $CO_2$ impact would be the equivalent of taking one in four cars off the road.

What Should Be Done?

• Reduce Waste
  • Reduce office paper waste by implementing a formal policy to duplex all draft reports and by making training manuals and personnel information available electronically.
  • Improve product design to use less materials.
  • Redesign packaging to eliminate excess material while maintaining strength.
  • Work with customers to design and implement a packaging return program.
  • Switch to reusable transport containers.
• Reuse
  • Reuse office furniture and supplies, such as envelopes, file folders, and paper.
  • Use durable towels, tablecloths, napkins, dishes, cups, and glasses.
  • Encourage employees to reuse office materials rather than purchase new ones.
• Recycle
  • Recycling in 2010- USA: By recycling almost 8 million tons of metals (which includes aluminum, steel, and mixed metals), greenhouse gas (GHG) emissions were eliminated totaling more than 26 million metric tons of carbon dioxide equivalent. This is equivalent to removing more than 5 million cars from the road for one year."
• Donate/Exchange
  • old books
  • old clothes
  • old computers
  • excess building materials
  • old equipment to local organizations
• Employee Education
  • Send out recycling reminders to all employees including environmental articles.
  • Train employees on recycling practices prior to implementing recycling programs.
  • Conduct an ongoing training process as new technologies are introduced and new employees join the institution.
• Conduct outreach program adopting an ecologically sound waste management system which includes:
  • waste reduction
  • segregation at source
  • composting
  • recycling and re-use
  • more efficient collection
  • more environmentally sound disposal