Page 88 - Solid Waste Analysis and Minimization a Systems Approach

66 BACKGROUND AND FUNDAMENTALS OF SOLID WASTE ANALYSIS AND MINIMIZATION

Drawbacks and limitations of this study were

■ Solid waste generation rates were only determined for entire countries, not individ-
ual companies.
■ The study did not examine waste stream compositions or recycling.

This study was useful in that it mathematically predicted solid waste generation
quantities. The study used historical data to aid in prediction. The major drawback is
that only entire county generation data was studied and no compositions were ana-
lyzed. This research identified the variables that were significant in predicting the solid
waste amounts for entire countries. The variables were population and GDP. Applying
this to individual company generation quantities, the number of employees, and sales
were tested to examine if they were significant in predicting generation.

2.10.6 SOLID WASTE ESTIMATION METHODS

Various waste-assessment methods have been developed to estimate solid waste gen-
eration for businesses. These methods assess waste, but do not predict or evaluate it.
Most of these methods lack the versatility and scalability to apply nationally. Most of
these methods require substantial data collection, before the waste estimation can
begin. This significantly adds to research costs, hence reducing the usefulness of the
methods. This research overcomes these problems by developing a standardized sta-
tistical system that is scalable and versatile.
The U.S. government developed and researched some of these waste-estimation
methods (U.S. Army Corps of Engineers, 1990). For example, the U.S. Army Corps
of Engineers developed four forecasting techniques for solid waste service plans at
military facilities. The four techniques outlined by the Corps provide varying degrees
of accuracy. The research noted that the more precise an estimate must be, the more it
will cost to obtain. The solid waste forecasting techniques that the Corps developed
and researched include moving average forecasting, per capita forecasting, and two-
sampling forecasting methods that vary in the amount of samples taken. The Corps
rated each forecasting method based on cost and accuracy using a low, medium, and
high scale.
One common problem when measuring solid waste is the unit of measurement used.
Two primary solid waste measurements exist, volume and weight. To avoid confusion,
solid waste quantities should be expressed in terms of weight. Weight is the more
accurate measure because weight can be measured directly, regardless of the degree of
compaction. Weight records are also necessary in the transportation of solid waste
because the quantity that may be hauled on highways is usually restricted by weight
limits rather than volume limits.
Because some recycling and solid waste data are obtained by volume (for example,
cubic yards), the use of standard volume-to-weight conversion factors is an essential
element of the recycling measurement method. EPA developed numerous conversion
factors for volume to weight from past research (www.epa.gov). The conversion fac-
tors are given in terms of density (mass/volume). The use of conversions factors is
often important when conducting waste assessments and recycling surveys. Many