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Garbage

 

Overview

It's hard to imagine scientists having much to do with garbage. But as the solid waste crisis grows, simple garbage disposal will require some high-tech solutions. While getting rid of garbage has always been a problem, it only recently has hit epidemic proportions. For almost 7,000 years, people disposed of solid waste by gathering it up, carting it out, and dumping or burying it in an isolated place. Crude as it was, this system worked because most of the solid waste consisted of biodegradable organic compounds that easily decomposed. In addition, the volume of trash was much lower than now because there were fewer people and less packaging waste. Over the last 50 years new synthetic materials have been introduced into the waste stream, complicating the problem. These materials are not biodegradable and some produce toxic residue. This has led to tighter environmental controls on landfills. With open space in short supply, many communities are literally drowning in municipal solid waste. Before a community can decide how to safely and efficiently dispose of solid waste, it needs to define exactly what solid waste is. It may sound funny, but all garbage is not created equally. Waste from industrial centers is very different from the waste generated on farms. Urban apartment garbage bears little resemblance to the household waste from suburbs. Before composting, recycling, or waste-to-energy systems can be considered, scientists must analyze the waste stream in detail. First, investigators calculate how much of the waste from many different samples falls into basic categories, such as glass, plastics, metals, paper, and food waste. They can then predict the BTU value of the garbage, the volume of recyclable material, and how much of the waste is biodegradable. Scientists also evaluate the effectiveness of different disposal techniques. If you add up the amount of food, yard, and paper waste generated by a typical American family, landfills appear an ideal option. After all, these materials--which are biodegradable--make up almost 70% of the garbage. Unfortunately, little oxygen or water exists inside a landfill to help the decomposition process. Scientists have found that even after 50 years, much waste in landfills is still quite fresh. By monitoring decomposition rates and end products from other disposal techniques, they can create disposal systems that are safe, efficient, and economically viable.

Activity

According to 1988 figures from the Environmental Protection Agency, the typical American throws away about five pounds of trash each day. Of that amount, 40% is paper, 17.5% is yard waste, 8.5% is metals, 7.0% is glass, 8.0% is plastic, 7.5% is food waste, and 11.5% is miscellaneous materials. By analyzing your own household waste stream, you can see how you compare. Materials
  • kitchen scale
  • bathroom scale
  • large plastic bucket
  • rubber gloves
  1. Set up a data chart with the categories listed in the solid waste breakdown above. To be accurate, you must weigh your waste every day for a month. (Note: Adapt time frame to fit your schedule.) For even greater precision, place cardboard, magazines, and newspapers into a separate category from other paper. If you currently recycle or compost any household waste, include the material in the weight analysis, and then keep a separate column for items recycled. This line will serve as a credit on your final garbage balance (so subtract this weight from your total garbage weight).
  2. Each day, separate your garbage into the various components to be weighed. Wear plastic or rubber gloves. To minimize mess, store and weigh organic food waste in a plastic bucket. Make sure you subtract the weight of the bucket each time you weigh the materials in it and wash it out each night. Weigh other materials like cans, bottles, and plastic containers when they are empty and dry. You can use a box to weigh them, but make sure you subtract the box's weight. For yard waste and larger bulk items, use the bathroom scale and record the weight to the nearest kilogram or pound.
  3. After recording the data for a month, add up the total weight for each category. Then add up all of the category subtotals to get the number of pounds of solid waste generated by your family in one month. Divide this number by the number of people in your household. Remember, babies count as a whole person!
  4. Divide each category subtotal by the total weight of garbage produced to get the weight percent for each category. If you do recycle or compost, divide that amount by the total amount produced to determine how much you are saving. Make a chart or graph of each category. Questions
    1. How do your numbers compare with the national averages? What factors might account for the differences?
    2. How would your numbers compare if you kept track of your garbage for a whole year? Are there any seasonal variations in waste generation?
    3. How much could you effectively reduce your household waste by using a source-management program, such as composting yard waste and recycling newspapers, bottles, and cans?

Resources

  • Dickson, N. (1991) Composting to reduce the waste stream. Ithaca, NY: Northeast Regional Agricultural Engineering Service.
  • Earth Works. (1989) Fifty simple things you can do to save the planet. Berkeley, CA: Earthworks Press.
  • Rathje, W. (1991, May) Once and future landfills. National Geographic, pp. 117-134.
  • Rathje, W, & Murphy, C. (1992) Rubbish! The archaeology of garbage. New York: Harper Collins Publishers, Inc.
  • 3-2-1 Contact Extra videotape: The Rotten Truth. GPN: (800) 228-4630.