Aerosol Ca.n Management
in
HHW Programs
Presented at the
1993 National HHW Conference
in
Burlington, Vermont
by
Wayne Turner
HHW Management Coordinator
City of Greensboro
Greensboro, North Carolina
on
Tuesday, November 9,1993
1.
Introduction
I
It’s time to take a closer look at aerosol can management in HHW Programs. The mysterious nature
of the closed, pressurized aerosol can has kept it from gerring its proper share of atrention from
otherwise aggressive HHW Managers bent on squeezing the last dollar out of an already tight budget
by bulking everydung possible. The liquid contents in aerosol cans have, in large part, been ignored
as candidates for consolidation. Consequently, HHW Managers have accepted the idea that responsible aerosol management means simply packing the cans in a steel drum and shipping them to a
hazardous waste incinerator. The moderate costs of aerosol can disposal has also contributed to this
attitude of indifference. But with the increased development and use of equipment designed to safely
and efficiently separate aerosol can components, it is time we reexamine aerosol can management in
HHW Programs. Aerosol cans may now represent the next frontier for waste minimization and
recycling efforts. By separating the individual components of aerosol cans, some important objectives of any HHW Program may be met.
1. Waste minimization
2. Beneficial reuse of products
3. Recycling of products
4. Reduced costs
II.
Background
Aerosol products are packaged in closed steel cans that come in a variety of sizes. Product net
weights usually fall in a range from 1 to 24 oz. Products including deodorants, hair sprays, automotive cleaners, household cleaners, paints and pesticides are packaged in aerosol form. Each aerosol
can also includes a propellant in the form of a compressed, liquefied gas such as butane or propane.
The compressed gas is responsible for creating the pressure which propels the product out of the can
when the valve is pushed open. The propellant is also responsible, in part, for the convenience of
traditional aerosol can management methods. Since most of the propellant gases are flammable, they
are easily categorized and shipped under the flammable =mas hazard class.
Most aerosol cans brought to HHW hgms are only parrially full of the ori-&al products. Because
they are only partially full, the cans themsehes may represent a large share of the total weight of
material destined for disposal. For example, if the net weight of the contents of a full aerosol can is
11 oz. which has only 10% left in it and the can weighs 4 oz., then the can represents 78.4%of the
total weight. Of course, if aerosol cans are completely empty, they should be recycled or landfilled,
whichever is appropriate in a given locale.
At many HHW Collection Programs, aerosol cans are simply collected and placed directly in drums
for shipment and disposal. This traditional method of aerosol can disposal packa,$ng is called ‘lab
packing’ or PLC (packed lab chemicals). It is also sometimes called ‘loose packing’ since aerosols
arc seldom packed with any absorbent material. The proper management of aerosol cans requires
that those with any residual contents be disposed of as hazardous waste because of the presence of
the flammable propellants. Aerosol cans normally are sent to hazardous waste incinerators for
disposal.
218
Recently some companies have developed systems which can safely separate the liquid contents and
propellants from the can. There are varying levels of sophistication to the different brands of equipment but what they all have in common is that they allow the liquid contents in the aerosol cans to be
collected in a drum. This is accomplished by puncturing the can with either a hand operated or
automated can punch. Some systems recover the propellant gases in a cylinder for reuse or disposal.
Other systems simply use an activated charcoal filter to absorb the propellant gases. The depressurizing of aerosol containers in order to recover or filter the propellants and bulk the liquid contents
prior to disposal can be a huge source of savings to HHW Programs over the traditional PLC method
of disposal. This report demonstrates the cost effectiveness of such an alternative method to aerosol
can disposal.
111.
Discussion
As stated above, there is a wide range of products that come in aerosol form. However, the most
prevalent ones that are brought to HHW Collection Programs are paints and pesticides. This discussion will focus on these two categories of aerosol products. The most direct and useful method to
compare costs for disposal of aerosol cans is on a per can basis. However, since no data exists
showing a per can disposal cost for aerosol cans, it will have to be calculated. Although this calculation may be done on the basis of either volume or weight, data on aerosol product weights is far
more plentiful. Using this data, the steps necessary to do this are as follows.
1. Determine aerosol net product weight
2. Calculate number of aerosol cans emptied in drum
3. Calculate disposal cost per aerosol can
4. Calculate savings per can
1. Determine Aemo1 Net Product Weiyht
In order to determine the net weight of aerosol paints and pesticides, product weight information on
as many different brands as possible was obtained from aerosol cans in local retail stores and from
l2
T
Distribution of Aerosol Product Weights in Retail Stores
(Grouped by Product Type)
Pest.
Paint
Hafr
Deod.
L9 Aut0
Fa C l n r .
-..
-
Product N e t W e l g h t (in 02.)
Figure m-1
219
aerosol PLC packing slips from HHW collection events. The data gathered from the retail stores was
analyze&and sorted by product type. When grouped by product type, as shown in figure III- 1, the
aerosol product data from retail stores reveals that most paint products are packaged in the 11 - 12
oz. weight range. Of the 11 brands of aerosol paints from which information was taken, 4 brands
were packaged only in the 12 oz. size, 4 brands only in the 11 oz. size, 1 brand in both the 11 and 12
oz. size, 1 brand in both a 12 oz. and 15 oz. size and 1 brand in a 3 oz. size. Eleven of the 13 cans
examined, or 85.6%,fell within the 11 - 12 oz. weight range. It can also be Seen that pesticides,
appear to be packaged in sizes that generally range from 14 - 17 oz. in weight. Of the 5 brands of
aerosol pesticides from which information was taken, only one packaged the product in a can that
had less than 14 oz. of product, Six of the 9 different cans examined, or 66.7%,fell within the 15 17 oz. weight range. From this we can conclude that most aerosol paints are packaged 11 - 12 ozJ
can and most aerosol pesticides are packaged 15 - 17 oz./can.
Distribution of Aerosol Product Weights from HHW Programs
2500
2000
m
c
a
1500
u
*
0
0
a:
1000
500
0
2
3
4
5
6
7
8
9
IO 1 1
12
13
14
IS 16 17 18 19 2 0 2 2 24 3 6 40
Product N e t Weight (In
02)
Figure III-2
By examining aerosol can data from HHW collection days along with the data from the retail stores,
a definite pattem of can sizes and product types emerges. Packing slip data from HHW aerosol lab
packs, representing over 5,400 aerosol cans, was examined. The net product weight for each aerosol
can packed in the drum was recorded from the packing slips. The data was then analyzed and plotted
graphically. The results, shown in figure III-2, reveal that of all aerosol cans included in the investigation, 41.2%of them contained 12 oz. and 21.1%contained 16 oz. of product when full. Since all
the aerosol cans were shipped under the flammable gas hazard class, the waste description on the
packing slips did not indicate what type of product was in each lab pack. However, if we apply the
data from Figure III-1 to this data, we can conclude that most of the 12 oz. products were paints and
most of the 16 oz. products were pesticides. We may also conclude that the choice of aerosol paints
and pesticides for management review is sound since they represent a large share of the total aerosol
waste stream in HHW Programs.We can now select a 12 oz. product weight for paints and a 16 OZ.
product weight for pesticides to use in further calculations in this discussion. These product net
weights and additional important information necessary for calculating the disposal cost/can are
summarized in Table III-1 below.
220
Aerosol Can Management Assumptiom
Net wt. of aerosol paint products
Net wt. of aerosol pesticide products
N e t w t . o f liquids in a 55 gal. steel drum (50 gals)
Disposal cost f o r PLC aerosol cans
Disposal cost f o r bulk liquid paints
Disposal cost f o r bulk liquid pesticides
12 0 2 .
16 0 2 .
400 l b s
6,400 0 2 .
$475/drum
$ 200 / d r u m
$588 / d r u m
Table III-1
The figure for the net weight of liquids in a 55 gallon drum was computed by assuming the liquids
would have an estimated weight of 8 pounds per gallon. The drums are assumed to be filled to 50
gallons, thus allowing enough freeboard (headspace) for expansion. The disposal costs for lab
packed aerosol cans and bulked liquids for each of the two categories were obtained from two
nationally known commercial hazardous waste companies. One company provided mainly a hazardous waste collection and transportation service while the other was a full service company providing
collection, transportation and ultimate disposal of materials at their own permitted facilities. The cost
figures, two each for paints and pesticides, were very close, so the average used in table ID-1should
be very consistent industry-wide. The substantially lower cost to dispose of a drum of buked paints
over a drum of PLC aerosol paints is due to the fact that the bulked paints can be beneficially reused
through a fuels blending program, whereas the lab packed cans would have to be incinerated. Disposal of high-btu paints through a fuels program is typically much less expensive than incineration.
On the other hand, note that the cost to dispose of a drum of bulk pesticides is somewhat higher than
the cost to dispose of a drum of PLC aerosol pesticides. However, since a greater number of aerosol
cans can be decanted into a drum than can be lab packed into one, the higher drum cost should be
offset by the greater consolidation of material.
. 1.nto Drum
2. C a l c W the Number 0f Cans Emptled
To calculate the number of aerosol cans that can be emptiedkto a 55 gallon drum, we need to know
the weight of the product remaining in the cans, Since there are no data available on the amount of
aerosol products remaining in cans in HHW Programs, another equally useful approach would be to
calculate a range of values that represents the number of cans that can be emptied into a drum depending on how much product remains in the cans. To do this, we simply apply a remaining product
factor (0%- 100%in 10%increments) to the original product net weight to calculate a range of
remaining product weights per can. Table III-2 shows the results of this calculation for both the paint
and pesticide products. The number of cans/drum was computed by dividing the 6,400 02. drum
capacity by each remaining product weight value. The two waste streams must be shown separately
because, 1) once decanted they have significantly different disposal costs, and 2) their product net
weights are different, both of which will affect the disposal cost per can. Using the values for the
number of cans that can be emptied into a 55 gallon drum,we can now calculate disposal costs/cm.
221
I
Number of Cans Emptied into a 55 gallon Drum
% Product
Remaining
10
20
30
40
50
60
70
80
90
100
Paints
Rem. Prod.
Number
Cans/Drum
W t . i n Oz.
1.20
2.40
3.60
4.80
6.00
7.20
8.40
9.60
10.80
12.00
5,333
2,667
1,778
1,333
1,067
889
762
667
593
533
Pesticides
Number
Rem. Prod.
W t . i n 02.
CandDrum
1.60
3.20
4.80
6.40
8.00
9.60
1 1.20
12.80
14.40
16.00
4,000
2,000
1,333
1,000
800
667
57 1
500
444
400
Table lII-2
3. #calculateDisppsal Costs Per Aerosol Can
With the infoxmation we now have, we can calculate the disposal cost per can for both lab packed
and bulked aerosol cans. The lab pack calculation is very straightforward yet requires one additional
piece of data.
To calculate the cost/can for lab packed aerosols, we need to know how many cans will fit into a 55
gallon drum. This has been a most Micult piece of data to obtain. Although tens of thousands of
drums of lab packed aerosols have been shipped from HHW Programs, very few people have found
it necessary to know how many cans are in them. Moreover, since the number of cans that will fit
inside a drum is more a function of their volume than weight, it is unreasonable to assume that it can
be computed by dividing the weight of a can into the weight of a drum full of cans. It is important to
note that products having the same net weight may be packaged aerosol cans of different physical
size. However, some HHW programs now bulking aerosol products have conducted some can counts
during the initial collection and sorting of the aerosols. Information from these programs indicates
that approximately 234 aerosol cans will fit inside a 55 gallon drum. This information is used to
compute the cost/can for lab packed aerosol cans shown below in Figure III-3. The $2.03 figure is
calculated by dividing the $475/drum lab pack cost by the 234 caddrum capacity of the lab pack.
Disposal Cost/Can for Lab Packed Aerosol Cans
Disposal cosUdrum for aerosol lab packs =
Number of aerosol cans/drum =
Disposal costkan for aerosol lab packs =
Figure III-3
222
$475/drum
234/drum
$2.03/can
Following the same format for the calculation of the number of cans that can be emptied into a drum
for bulked aerosol products, a range of values are shown for the bulk disposal costs depending on
how much product remains in the can. Table a - 3 illustrates these costs for the two aerosol products
being discussed, paints and pesticides. The disposal cost/can is computed by dividing the $2OO/drum
cost for bulk paint and the $588/drum cost for bulk pesticides by each cans/drum value. Empty
aerosol cans should represent no cost to HHW Programs (i.e. recycled or landfiied. In fact, evtry
HKW Program should have as one of its key educational components, information encouraging
consumers to use up products when appropriate and to toss the empty containers in either the recycling bin or the garbage.) On the other hand, disposal costs for full aerosol cans that are bulked
would cost no more than $0.38/can for paint products and $1.47/can for pesticide products. Obviously, most aerosol cans brought to HHW Programs would most likely fall somewhere between
these two extremes of being completely full or empty. And although it becomes readily apparent that
a sigrufcant cost savings can result from bulking aerosol products, let's continue and calculate the
savings for the entire range of product remaining values.
Disposal Costs/Can for Bulked Aerosol Products
Paints
% Product
Disposal
Remaining Cans/Drum
Cost/Can
10
20
30
40
50
60
70
80
90
100
5,333
2,667
1,778
1,333
1,067
889
762
667
593
533
0.04
0.08
0.1 1
0.15
0.19
0.23
0.26
0.30
0.34
0.38
P e s t ic i d e s
Disposal
C a n s I D r u m CostICan
4,000
2,000
1,333
1,000
800
667
57 1
500
444
400
0.15
0.29
0-44
0.59
0.73
0.88
1.03
1.18
1.32
1.47
Table III-3
4. s v'n3
A
e
r
o
s
o1 P
rodm
As shown in Table ID-4, the savings that can be realized by bulking aerosol products are substantial.
The savingskan figures are computed by subtracting each bulk disposal cost/can from the $2.03
PLC cost/can. A minimum of 81.53% of the disposal costs for aerosol paints using PLC packing
methods can be saved by using the bulk packing method. A minimurn of 27.64%of the disposal
costs for aerosol pesticides using PLC packing methods can be saved by using the bulk packing
method. Using infomation from paint products remaining in gallon cans and data froman HHW
Program that is bulking aerosol paints, it is safe to assume that the average amount of product remaining in aerosol cans will fall within the 25% - 45% range. This means that savings should fall
within the range of 90% - 96% for paints and 63% - 85% for pesticides. It should be noted that the
savings for bulking pesticides may be somewhat offset by higher labor costs due to the possible
necessity of using a higher level of PPE during the processing of the waste.
223
SavingdCan for Bulked Aerosol Products
W Product
Remaining
10
20
30
40
50
60
70
80
90
100
Paints
Savings
W Savings
per Can
per Can
1.99
1.95
1.92
1.88
1.84
1.80
1.77
1.73
1.69
1.65
98.15
96.31
9 4.46
92.6 1
90.76
88.92
87.07
85.22
83.37
8 1.53
Pesticides
Savings
X Savings
p e r Can
p e r Can
1.88
1.74
1.59
1.44
1.30
1.15
1 .oo
0.85
0.71
0.56
92.76
85.53
78.29
7 1.06
63.82
56.59
49.35
42.12
34.88
27.64
Table m-4
IV.
Conclusion
At the outset of this report, some important potential benefits of separating the components of
aerosol cans were enumerated. This report has demonstrated how each of these benefits can be
achieved. Waste can be minimized by separating the hazardous liquid from the cans, aerosol paints
which are bulked can be reused beneficially in a fuels blending program, the empty steel cans can be
recycled and reduced disposal costs can result in substantial savings. Every HHW Program Manager
in the United States has probably been, at one time or another, in a position of trying to explain why
their program costs so much. Over the 10 to 13 years that HHW Programs have been in existence a
great deal of progress has been made toward minimizing wastes and reducing disposal costs. Lets
not let the mysterious nature of the aerosol can waste stream lessen our diligence. With the advent of
improved aerosol can evacuation techniques and equipment, it is now time to take a look at how its
use can save your program money. The cost savings that can be realized by utilizing this method of
waste processing makes it worth investigating.
Appendix A contains the names of companies that manufacture and sell aerosol can evacuation
equipment.
Note:
If you have any questions about aerosol can management in HHW Programs, I will be happy to try
and answer them. My phone number and address is shown below.
B. Wayne Turner
HHW Management Coordinator
City of Greensboro
P. 0. Box 3 136
Greensboro, NC 27402
(919) 373-2167
224
Appendix A
Aerosol Can Evacuation Equipment Manufacturers
Katec (Aerosolv)
P. 0. Box 3399
Virginia Beach, VA 23454
Mike Campbell
(804) 428-8822
Aervoe-Pacific Company
1198 Sawmill Road
Gardnerville, NV 89410
Mark Williams
1-800-548-4656
American Gas Products
7200 Greenleaf Avenue, Suite 250
Whittier, CA 90602
Robert J. Hohne
(3 10) 693-2431