Urban Waste

• Methane is a potnt greenhouse gas emitted when biodegradable waste, mostly food and paper, decomposes anaerobically. If this is not tackled, landfill sites will produce 8-10% of the global polluting greenhouse gas emissions by 2025
• Waste increases by about 7% each year, due to population growth and also economic development
• In urban areas where there are large concentrations of people, the amount of municipal solid waste (MSW) is particylarly high and set to increase
• In 2002 there were 2.9 billion urban residents producing about 0.64kg of MSW per person per day, this is predicted to increase by 2025 to 4.3 billion urban residents generating about 1.42kg per person per day
• Solid waste is seen as an 'urban issue' because urban residents produce about twice as much waste as rural counterparts
• There is concern in low income countries where they do not have facilities to properly dispose of hazarous waste, annually, 77,000 tonnes of hazardous waste is deposited in Cairo
• Residential waste

  • Generated by households
  • Includes food wastes, paper, cardboard, textiles, electrical waste
• Industrial Waste

  • Generated by light and heavy manufacturing, construction sites, power plants
  • Includes housekeeping wastes, packaging, food wastes, hazardous wastes
• Commercial Wastes

  • Produced by stores, hotels, restaurants
  • Includes paper, cardboard, plastics, food
• Institutional Wastes

  • Generated by schools, hospitals, prisons
  • Includes paper, cardboard, plastics, food
• Construction and Demolition

  • In some cities can represent as much as 40% of total waste stream
  • Generated by construction sites, road repair, demolition
  • Includes wood, steel, concrete, bricks
• Urban Services Waste

  • Generated by street cleaning, landscaping, parks, beaches
  • Includes street sweeping such as tree trimmings and general waste from parks and beaches
• Impacts of Increasing Waste Generation

  • Cost of collecting and treating waste are high, in LICs, solid waste management consumes around 20-25% of urban budgets
  • Waste produces methane and contributes to ground and water pollution
  • Untreated or uncollected waste leads to health issues such as cholera and dengue fever
  • Authorities struggle to collect waste
  • Cities are running out of landfill space
• 2012 Wrold Bank report on waste found 30-60% of MSW in LICs is uncollected. Egypt generated around 80 million tonnes of solid rubbish each year and there is only unofficialy waste collection
• Most LICs and lower middle income countries dispose of their waste in open dumps. Some of this in unregulated and not controlled by law. Solid waste not properly controlled can be a breeding ground for disease
• A survey conduced by UN-Habitat in 2009 found that in areas where waste is not collected frequently, the incidence of diarrhoea is twice as high and acute respiratory infections six times higher
• Resource recovery is the selective extraction of disposed materials for a specific next use, such as recycling, composting or energy generation
• Recycling is carried out when materials from which the items are made can be reprocessed into new products
• The world market for post concurred scrap metal is estimated at 400 million tonnes annually and 175 million tonnes annually for paper and cardboard. This represents a global value of $30 billion per year
• Urban Mining = the process of recovering compounds and elemts from products, buildings and waste which would otherwise be left to decompose in landfills
• Key advantages of recycling and recovery are reduced quantities of disposed waste and the return of materials to the economy, however there are issues such as energy required to operate material recovery and make them reusable
• Trade

  • Global waste trade is the international trade of waste between countries for further treatment, disposal, or recycling
  • Toxic or hazardous wastes are often exported from HICs to LICs
  • LICs do not often have safe recycling processes and facilities, so hazardous waste is not properly disposed of
  • International law e.g. Basel Convention introduced to prevent transboundary movement of hazardous waste, but it still occurs
• Incineration

  • Can reduce volume of disposed waste by up to 90%
  • General waste burned at high temperatures under controlled conditions to produce electricity and heat; energy from waste
  • Incineration without energy recovery is not preferred due to costs and pollution, open burning of waste causes severe air pollution
• Landfill (burial)

  • Placement of waste in excavations such as landfill sites
  • In LICs, landfill sites are often simply holes in the ground where open dumping occurs
  • In the UK most sites control and collect the gas released by decomposing waste
  • Greenhouse gas methane is produced, other chemicals like bleach and ammonia produce toxic gases
  • Landfill can also affect groundwater and contaminate water by leachates
• Submergence of waste in oceans is banned by the United Nations, but some companies have been dumping radioactive waste and other hazardous waste into coastal waters off Somalia
• Landfill

  • Advantages = facilities are properly sited with necessary controls, different waste types accepted and ordered
  • Disadvantages = unsightly, opposed by neighbouring residents, potential leaching of chemicals into water, production of methane, large space taken up
• Incineration

  • Advantages = can reduce waste volume by 90%, inactivate disease agents, reduce toxicity, produces energy
  • Disadvantages = expensive, not all waste is combustible, poses challenges of air pollution and ash disposal, unpopular with local residents
• Amsterdam is the cultural capital of the Netherlands, a densely populated, low lying country with a growing population and a diminishing amount of spare land
• The Dutch approach to waste is to avoid creating waste in the first place, recover the valuable raw materials from it and generate energy from incinerating residual waste. Approach known as Lansink's Ladder is Dutch legislation
• Landfill in Amsterdam

  • Lack of space and increasing waste meant the Dutch government took early measures
  • Increasing objections to landfill sites due to pollution
  • In 1995, landfill tax introduced to every tonne of material landfilled, this increased yearly until 2012 when landfill had reduced
  • Landfill ban on 35 categories introduced in 1995
  • By 2006, all targets of the Landfill Directive set for 2016 had been met
• Incineration in Amsterdam: the Afval Energie Bedrijf Plant

  • Waste-to-energy strategy, capable of producing 1 million MWh of electricity annually, also produces 300,000 gigajoules of heat annually
  • 1.4 million tonnes of waste brought to the plant each year, 600 trucks and one freight train per day
  • 64% of waste ending up at the plant is recycled
  • Flue gases are scrubbed and attempts are being made to close the loop for other by products
  • Next door is the Waternet treatment plant, works with the incineration plant for heat and energy and supplies sludge for incineration
• If the waste incinerated in Amsterdam was put into landfill, the CO2 emisisons would be 1036 kilotons as a result of methane gases, and even if these were burned off the total emissions would be 404 kilotons