CGP Urban Waste

• Three primary sources of waste in urban areas

  • Industrial waste
  • Commercial waste
  • Personal waste
• Industrial waste


  Waste that has been produced in the manufacturing process or from industrial activity e.g. in power plants or building sites. Industrial waste can include scrap metal, solvents and chemicals, which can be toxic or corrosive
• Commercial waste


  Waste that is produced by businesses, e.g. shops, restaurants, offices. Commercial waste often includes food, paper, cardboard and plastics
• Personal waste


  Waste produced by private homes. This can include plastic bottles, food packaging, newspapers, food waste, etc.
• Largest components of global waste

  • Organic material (46%)
  • Paper (17%)
  • Plastic (10%)
  • Glass (8%)
• The majority of waste is easy to manage, but some material is hazardous, e.g. medical waste
• Waste stream

  The flow of waste from its origin through to its eventual disposal
• Some products (e.g. paper, glass) can be recycled
• Others need to be broken down into their component parts and each part disposed of separately (e.g. by recycling, sending to landfill, processing to extract useful chemicals or metals, or treating to reduce risk)
• Economic characteristics


  As people get richer, they tend to consume more goods. This means that developed countries produce more waste (2.1 kg per person per day) than developing countries (0.6 kg per person per day)
• Main components of waste in developed countries

  • Paper (31%)
  • Organic material (28%)
  • Plastic (11%)
• Main components of waste in developing countries

  • Organic material (64%)
  • Plastic (11%)
  • Paper (5%)
• Waste streams vary between countries, but there is no clear-cut link to wealth. For example, Austria recycles 63% of all waste, whereas Japan only recycles 21%. Most developing countries do not have formal recycling systems, but many people collect recyclable goods from landfill and sell them to make a living
• Lifestyles


  The amount and type of waste produced varies depending on whether people live in the city or the country. Urban dwellers produce more waste than rural residents. People in rural areas produce more organic waste (e.g. food), and people in cities produce more manufactured waste (e.g. plastic, glass). The facilities available to people affect the waste streams they use - for example, people are more likely to recycle waste if recycling facilities are easily accessible, and if authorities encourage them to. Diet is likely to affect waste components and streams - e.g. producing processed food creates waste, and finished products tend to come in a lot of packaging, in contrast, fruit and vegetables tend to produce more compostable waste (e.g. vegetable peelings) and less packaging
• Attitudes

  Many developed countries have a throw-away culture - e.g. electronics are replaced regularly and clothing may be bought, worn a few times then thrown away. This results in high levels of waste, much of which cannot be recycled or has a long and complex waste stream. Increasing concerns about health may cause people to throw away food that is near or just past its sell-by date, resulting in high levels of food waste. People have different attitudes towards the environment - people who are concerned about the environmental impacts of excess waste are more likely to reuse or recycle waste. In some groups, there has been a recent move towards a decrease in consumption and waste. For example, many freegans forage for food, including salvaging it from supermarket bins, repair broken goods and give away things they don't need, instead of throwing them away
• Methods of waste disposal

  • Unregulated/untreated
  • Recycling
  • Incineration
  • Recovery
  • Burial/landfill
  • Submergence
  • Trade
• Unregulated/untreated

  Liquid waste enters water courses. Solid waste is let on the street. Chemicals from waste can enter the environment. Animals and birds can be harmed if they swallow or get tangled in plastic waste
• Recycling


  Reduces demand for raw materials, which decreases the environmental impact of resource extraction. Waste is reprocessed into new products. Producing recycled products generally uses less energy than making them from scratch, so less greenhouse gases, such as CO2, are emitted. However, recycling requires separate collections and the construction of new facilities to process waste - these contribute to greenhouse gas emissions and air pollution
• Incineration


  Reduces the amount of waste going to landfill, but it emits greenhouse gases and causes air pollution. Waste that is burned can be used to generate electricity
• Recovery


  Involves using waste instead of new products, e.g. waste concrete can be crushed and used as a base for new roads and buildings. This reduces the amount of waste being sent to landfill and means that lower natural resources are exploited because goods are reused
• Burial/landfill


  Waste is placed in disused mines, quarries or landfill sites. Many sites are lined with clay or plastic to prevent leaching of chemicals into the environment, but if sites are not properly regulated, hazardous chemicals can contaminate groundwater, while gases such as methane from decomposing waste cause air pollution. Some countries collect gases for energy production, reducing air pollution and fossil fuel use
• Submergence

  Disposing of waste by dumping it in oceans is illegal, but it is still common in some areas, e.g. off the coast of Somalia. Submerged waste can release toxic or radioactive substances, damaging ocean ecosystems
• Trade

  Waste can be bought and sold by countries. For example, developed countries may pay developing countries to take their hazardous waste. However, developing countries may not dispose of hazardous waste safely, meaning that it can damage local environments, e.g. heavy metals can pollute groundwater and local watercourses
• Singapore has moved from landfill to incineration
• Singapore

  • It is an island off Malaysia, almost entirely urban. The amount of waste produced in Singapore increased from 1260 tonnes per day in 1970 to 8400 tonnes in 2015. Land is scarce, so waste management is important
• Singapore's waste disposal history

  In the 1960s and 1970s, most waste was sent to landfill sites around the city. In the late 1970s, the government changed their main waste disposal method to incineration with energy recovery. The first incineration plant was constructed in 1979. Today, there are four plants across the city which provide about 3% of Singapore's energy needs. Each incinerator is fitted with pollution control systems to limit greenhouse gas emissions
• Singapore's current waste disposal

  • Singapore now has only one landfill site, Semakau, which was built on reclaimed land between two small islands. It is lined with an impermeable membrane and a layer of clay to prevent leaching of chemicals. Once each area of the site is full, it is covered with topsoil to support vegetation. The landfill is now home to some species, e.g. Malaysian plants. In 2015, only 2% of waste was sent to landfill - 38% was incinerated and 60% was recycled (recycling facilities were built in 2001). Only waste that can't be recycled or burnt goes to landfill
• Pollution control systems cannot remove all harmful emissions from incinerators, and incinerators only last around ten years before they need to be replaced. The current landfill site is expected to be filled by around 2040