Management of solid waste Individually, come up with some management strategies for dealing with SDW. HINT. Think about the different stages on your diagram.

Learning outcomes All of you should be able to: Identify and describe possible management strategies for SDW Most of you should be able to: Evaluate the different management strategies

Minimising waste Best action that we can take is to produce less waste in the first place – reduce it Reuse it instead of it becoming waste Recycle it In Germany each household has 4 bins each for different types of waste. In India and China very little waste is food waste because it is not thrown away or it is fed to animals. In MEDCs up to 50% of waste is food waste!

Waste food

Composting Organic waste can be composted or put into anaerobic digesters. The methane produced can be used as fuel and the waste used as fertilizer or soil conditioners.

Recycling Separate waste materials and process them for reuse – the economics determine whether it is commercial or not. Some materials have a high production cost so recycling is particularly worthwhile e.g. aluminium cans Recycling an aluminium can takes 5% of the energy needed to extract it from the source, bauxite. It can be recycled indefinitely with no loss to quality. Recycling one can saves enough energy to run a TV for three hours.

Recycling in Mexico “the Journal of Solid Waste Technology and Management”… (2006)

Disposal of waste Landfill Main method of disposal – waste is taken to a suitable site and buried there. Cheapest method economically speaking. Living near landfill can cause health problems Carefully selected to be away from areas of high population density, water courses and aquifers. Lined with plastic liner to prevent leachate (liquid waste) Leachate is collected in pipes. Methane is either collected to produce energy or released to the atmosphere.

Disposal of waste Incinerators Burn the waste at high temperatures up to 2000°C. Sometimes the waste is pre-sorted. Reduces waste between 80-90% The heat produced can then be used to drive a turbine and produce energy or to heat buildings. Waste-to-energy incineration. In some all waste is burned but this produces air pollution. (burning plastics / heavy metals produces dioxins).

Mexico Read the section taken from the article on waste management in Mexico. What are the main methods used here? What are the problems with waste management in Mexico? What improvements are being made? What is going well?

Waste produced per capita / kg yr–1 The table below shows the different types of domestic waste and the amounts produced per capita each year in a city in a developed country. Material type Examples Waste produced per capita / kg yr–1 Organic material garden waste, food/kitchen waste, wood 188 Paper newspaper, writing paper, packaging, cardboard, milk cartons 91.2 Plastics soft drink bottles, plastic bags, plastic containers 25.1 Glass jars, bottles, plate glass 23.9 Metals steel cans, aluminium packaging and cans, copper pipes 14.4 Household hazardous paint, dry cell batteries, car batteries, fluorescent light bulbs 1.9 Miscellaneous ceramics (bricks, tiles etc.) rock, ash, soil 10.2 Total   354.7 [Based on Australian Bureau of Statistics data] Calculate the proportion of paper, glass, plastics and organic material combined as a percentage of total waste. (1) Outline and evaluate strategies for the management of the domestic waste in the table above. (3)

Mark scheme (a) 100 × = 92.5 %; (accept 92.0 to93.0 %) (b)To achieve full marks the answer must include at least one evaluation comment. most of the waste generated can be recycled or composted; some of the waste could be reused e.g. jars/bottles/textiles; composting and recycling would significantly reduce the amount of domestic waste going to landfill/combustion; hazardous wastes must be treated appropriately to reduce environmental damage; the advantages of reducing landfill should be explained to householders; incentives may be necessary to encourage householders to recycle rubbish; recycling is cheaper if householders sort their own waste; recycling will not continue if there is no demand for recycled goods; manufacturers may be made responsible for the final disposal of large items e.g. cars/refrigerators; 3 max Any other reasonable point.