Page 166 - Solid Waste Analysis and Minimization a Systems Approach
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144 THE GENERAL APPROACH FOR A SOLID WASTE ASSESSMENT
be given in terms of weight (tons per year) and volume (cubic yards per year). The key
questions that are answered from this analysis are
■ What are the waste streams generated from the facility and how much?
■ Which processes of operations do these waste streams come from?
■ Which waste streams are classified as hazardous and which are not? What makes
them hazardous?
■ What are the input materials used that generate the waste streams of a particular
process or facility area?
■ How much of a particular input material enters each waste stream?
■ How much of a raw material can be accounted for through fugitive losses?
■ How efficient is the process?
■ Are any unnecessary wastes generated by mixing otherwise recyclable hazardous
materials with other process wastes?
■ What type of housekeeping practices are used to limit the quantity of wastes generated?
■ What types of process controls are used to improve process efficiency?
■ How much money is the company paying to dispose of solid waste, and how much
revenue does it generate from the sale of recyclable materials?
To answer these questions and generate the baseline data, the existing records col-
lected, the data gathered during the waste audit, and the team member knowledge will
be used. Additional data collection or verification may be required during the analysis
portion. The first step in the data analysis process is to summarize the collected data
in one document. The most efficient manner to accomplish this is with the use of a
linked spreadsheet. The data collected from the waste audit and records review are
input into a linked spreadsheet to extrapolate annual generation and break down dis-
posal costs and revenues. The information entered into this spreadsheet includes the
data collected from each collection form during the waste audit. After the data are
entered, the spreadsheet can be created to automatically calculate annual generation
based upon predetermined density factors. The spreadsheet in Fig. 8.20 provides a for-
mat to enter these data and includes common density factors.
After all the data have been entered into the spreadsheet, annual generation in terms of
weight and volume can be tabulated. To estimate the annual waste stream in terms of both
weight and volume is very important because, in general, waste haulers charge based on
volume (cubic yards that fill a dumpster) and processors pay for recyclable materials based
on weight (tons in a bale). Following is an example calculation for cardboard (OCC).
3
A company reported using a dumpster of 12 yd that was used exclusively for com-
pacted OCC (cardboard) that was emptied two times per month by a recycling vendor.
These data were converted into annual tonnage using the following equation:
Tons per year = (dumpster size in cubic yards) × (times emptied per month)
× (12 months per year)
× (EPA average material density − tons/cubic yards)
3
3
OCC = (12 yd ) × (2/month) × (12 months/year) × (0.45 tons/yd )
= 129.6 tons of OCC per year