Page 132 - Materials Chemistry, Second Edition

CAT3525_C04.qxd 1/27/2005 11:12 AM Page 103
Characterization of Solid Waste 103
EXCEL EXERCISE

WASTE CHARACTERIZATION
FILE NAME: CHARACTERIZ.XLS

Background
For this exercise, you will work with waste sampling data for the town of Goat Cheese, WI from
January 2001 through April 2002. The data are stored on a Microsoft Excel spreadsheet.
Waste is collected and the trucks are brought to the transfer station for unloading. Once a
month, a truck is randomly selected and dumps its contents on to a secluded portion of the tipping
room floor. Three university students were hired to sort the wastes into designated fractions and
then weigh the fractions.
At each sampling date, a subsample of this waste was fed into a micronizing mill (a small shred-
der) and the shredded mixture was weighed and combusted in a tabletop furnace. The ash was collected
and weighed. A separate subsample was shredded and placed in a bomb calorimeter. The heat content,
measured in BTU/lb, was determined.
The data for this exercise can be located at www.crcpress.com/e_products/downloads/
download.asp?cat_no=3525

Tasks
1. Calculate the percentages of each waste component for each month. What is the pre-
dominant fraction in the waste?
2. Determine the average values for each component over 2001.
3. Plot the data for total paper, plastics, food waste and yard waste, over the year 2001.
What trends do you observe?
4. Plot the data for BTU and ash content at each sampling date. Are any seasonal trends
observed?
5. Finally, perform a simple regression analysis of the heat content vs. ash content data. Is
there a significant correlation between the data sets? What is the correlation coefficient?