SHWPCE
Bill Bardin
Homework 2
2.2
Estimate the amount of paper of different categories that are used by the RPI Hartford building.
One approach to the problem would be:
1. Determine the types of paper and divide them into distinct categories.
2. Review the purchases for each category for the past 12-months.
3. Tabulate the total purchases in each category for the 12-month period.
2.5
Moisture transfer deals with the fact that certain solid waste tends to be hydroscopic. Typically,
paper entering the recycle process is realtively dry. Since most recycling operations are
conducted in the open environment the opportunity for moisture absorption from rain and
humidity is very high. The result is moist to wet paper at the recycling station.
This is an important consideration when designing equipment for the downstream processing of
the paper. The heat value of the waste stream is directly impacted by the moisture content as
higher moisture content will require more energy to first dry the paper reducing the effective
BTU content.
2.7
The recycle logo with a number (code) refers to the plastic category codes – 1 through 7.
Switch refers to changing the way plastic is sorted – e.g. from reading the codes to looking at the
plastic and sorting by eye.
2.8
How have the plastics industry responded to restrictive legislation about the use of plastic.
There are numerous players in the plastic industry and the response has run the gamut of possible
responses. Many manufacturers have been resistant to change and others have been somewhat
agreeable to many of the legislative efforts. From the viewpoint that plastics are bad many
companies have mounted advertising campaigns extoling the benefits of plastic vs. paper and
cardboard. Some of those benefits are; lighter weight, the ability to recycle, durability, water
resistance. They have also taken legal action against laws restricting plastics use, primarily
plastic bags. Another tactic has been to attack the alternatives such as paper and cardboard. On
the flip side, the industry recognizes that responding to consumer demands are key to
maintaining and expanding business. One of the biggest changes in recent time has been the
move to eliminate BPA from food grade plastic containers, especially water bottles.
2.10
Heat value is determined by burning a specified amount of trash in a calorimeter.
= BTU’s (as received).
Y = Moisture content
P = Pounds of trash
Call the percentage of water by weight Y.
The heat value for Z pounds of trash as received is Z*X
The heat value for Z pounds of trash dry is Z* (X/X-Y)
Call the amount of ash produced A. The heat value of Z pounds of trash ash free and moisture free is:
Z*(X/(X-Y-A))
2.11
California requires communities to divert 50% of MSW from landfills.
One of the main reasons that California and some others are enacting mandatory recycling requirements
is to increase the lifespan of their landfill sites. Absent such efforts, the landfills would quickly reach
capacity and more sites would be required. The NIMBY syndrome makes siting of these is quite
difficult.
Solid Waste can be broken down into the following categories:
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Mixed Household Waste (not recycled) - MHW
Recyclables - R
Commercial Waste - CW
Construction and Demolition debris - CD
Leaves and miscellaneousl - LVS
It is likely that California calculates their 50% by the formula
R+ CD+ LVS/MHR+R+W+CD+LVS
This is a misleading formula insofar as CD and LVS are typically not brought to the landfill the
requirement is designed to protect.
A more difficult – and more relevant formula is :
R/MHW+R+CW.
In this fraction the denominator is the list of things that CAN go into a landfill. The numerator is the
amount that doesn’t go in (but could). Thus the higher this fraction the longer the landfills last.
2.12
Shelton allows any plastic marked 1-7 into its single stream recycling.
2.19 Using the chart on page 54 to crush cardboard and achieve a 60% volume reduction you would
need to use 10-12 foot/lbs of energy per pound of cardboard.
Total MSW Generation has gone up from 2008 (though declining slightly in 2010 and declining on a per
capita basis):
Diversion due to recycling has increased dramatically in absolute and percentage terms:
All figures and graphs are taken from: http://www.epa.gov/epawaste/nonhaz/municipal/
2.20 Total MSW Generation has gone up from 2008 (though declining slightly in 2010 and declining
on a per capita basis):
Diversion due to recycling has increased dramatically in absolute and percentage terms:
All figures and graphs are taken from: http://www.epa.gov/epawaste/nonhaz/municipal/