Document ID: EPA-HQ-RCRA-2008-0329-0249
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-01-02T05:00Z

Materials Characterization Paper

In Support of the

Advanced Notice of Proposed Rulemaking –

Identification of Nonhazardous Materials That Are Solid Waste

Scrap Plastics

December 17, 2008

==================================================================

1. 	Definition of Scrap Plastics

Scrap plastics under consideration here comprise three categories of
material: scrap material from the manufacturing of plastic items,
off-specification (off-spec) manufactured plastic goods, and packaging
materials used in shipments to industrial users - typically plastic
film, pallets, and “peanuts.”

2.	Annual Quantities of Scrap Plastics Generated and Used

Sectors that generate scrap plastics:  

Industrial scrap plastics are generated from the manufacturing of
plastic products and packaging, and from off-spec manufactured material.
 

Plastic manufacturers (NAICS 325211) are responsible for generating
various plastic resins that are then combined and molded into products. 
This sector is responsible for plastic production; generators reuse the
vast majority of their manufacturing byproducts.  It is efficient to
rework this material back into industrial processes (OECD 2006 p.88). 
The efficiency stems from the fact that process scrap is typically made
up of single-type plastic.  However, even scrap from multi-layer food
packaging can be reworked into the original process provided that food
contamination is limited (Robertson 2005, p.26).

Data on the generation of scrap plastics are not readily available, but
the largest market for the use of virgin plastic resins is packaging. 
Packaging (NAICS 32611) accounted for 33 percent of plastic industry
sales in 2007 (ACC 2008a).

The second largest industrial market for virgin plastic, at 21 percent,
is the manufacture of consumer products (NAICS 31-33) (ACC 2008a).

The third and final substantial industry using plastic is building and
construction (NAICS code 23), with 17 percent of the market (ACC 2008a).
 PVC in particular is used primarily in plastic pipes (NAICS 32612)
(Ernes & Griffin, 1996, p.180). 

Quantities of Scrap Plastics Generated:   The Plastics Industry
Producers’ Statistics Group reports that the plastics industry in
North America produced approximately 46.4 million tons of thermoplastics
in 2007.  Polypropylene makes up the largest share of virgin plastic
production at approximately 9.7 million tons.  PVC is the only
halogenated plastic with substantial production in 2007, with 7.3
million tons (ACC 2008c).  Data from the Netherlands suggest that the
plastic processing industry is approximately 95 percent efficient, as
measured by the ratio of plastic scrap generated to plastic material
input (Joosten, et al, 2000, p.154).  Assuming U.S. plastic processors
are similarly efficient, the volume of plastic scrap generated would be
approximately 2.4 million tons.  Exhibit 1 lists the annual quantities
of virgin plastic generated in 2007 for each type of plastic. 

Data are not available on specific users and volumes of plastic scrap. 
One source suggests, however, that 75 to 90 percent of plastic scrap
from production of plastic products in the United States in the early
1990s was recycled due to the efficiency with which manufacturers can
reuse single polymer uncontaminated scrap in their production processes
(OECD 2006 p.88).  A representative of Holcim Group Support Ltd. reports
that some scrap plastic – typically off-spec products – is obtained
through direct agreements between specific producers and cement kilns
for fuel, but sources and quantities of plastics used are considered
competitive information throughout the industry (Guerra 2008).

Exhibit 1:  Overview of Plastic Production  in North America for 2007

Plastic Type	Annual Quantity 

Generated

(tons)

Low-density polyethylene (LDPE)	4.0 million

Linear low-density polyethylene (LLDPE)	6.8 million

High-density polyethylene (HDPE)	9.1 million

Polypropylene (PP)	9.7 million

Acrylonitrile butadiene styrene (ABS)	0.6 million

Other Styrenics	0.9 million

Polystyrene (PS)	3.0 million

Nylon	0.7 million

Polyvinyl chloride (PVC)	7.3 million

Thermoplastic Polyester (includes PET)	4.4 million

Total Thermoplastics

	46 million

Source: 

ACC Plastics Industry Producers Statistics Group, as compiled by Veris
Consulting, LLC

Trends in Generation:  

Plastic generation has remained constant over the last several years. 
Measured by weight, production of plastic grew 2.6 percent from 2003 to
2007, as shown in Exhibit 2 (ACC 2008e).  This is likely a reasonable
indicator of trends in production of scrap plastic.

Exhibit 2:  Summary of Plastic Markets from 2003 to 2007

Sector	Tons of Plastic Used

	2003	2004	2005	2006	2007

Transportation	2.4 million	2.4 million	2.4 million	2.3 million	1.7
million

Packaging	12 million	13 million	13 million	13 million	13 million

Building & Construction	7.2 million	7.8 million	7.7 million	7.7 million
7.1 million

Electrical/Electronic	1.4 million	1.5 million	1.5 million	1.3 million
1.0 million

Furniture & Furnishings	1.7 million	1.7 million	1.7 million	1.7 million
1.5 million

Consumer & Institutional	8.8 million	9.4 million	8.7 million	8.9 million
8.6 million

Industrial/Machinery	0.5 million	0.5 million	0.5 million	0.5 million	0.5
million

Adhesives/Inks/Coatings	0.6 million	0.6 million	0.6 million	0.6 million
0.5 million

All Other	1.0 million	1.1 million	1.1 million	1.0 million	0.8 million

Exports	4.5 million	5.0 million	4.9 million	5.0 million	6.2 million

Total Selected Plastics:	40 million	43 million	42 million	42 million	41
million

Source: 

ACC Plastics Industry Producers Statistics Group, as compiled by Veris
Consulting, LLC

Note:

 Selected plastics include LDPE, LLDPE, HDPE, PP, Nylon, PVC,
Engineering Resins, PS, ABS, Styrene-Acrylonitrile (SAN), Other
Styrene-Based Polymers, and Styrene Butadiene Latexes. Data from 2007 do
not include ABS, SAN, Other Styrene-Based Polymers, and Engineering
Resins.

An index from the same source reports sales and intra-company use of
major plastic resins in the fourth quarter of 2007 were slightly lower
than the first quarter of 2002, with a peak of 10 percent higher than
2002 in the third quarter of 2004 and a trough of 8 percent lower in the
second quarter of 2003 (ACC 2008f).  See Exhibit 3 below.

Exhibit 3:  Trend of Sales for Major Plastic Resins

Source: ACC Plastics Industry Producers Statistics Group, as compiled by
Veris Consulting, LLC

3.	Uses of Scrap Plastics

Fuel Uses: Combustion of post-industrial scrap plastic for energy in the
United States does not appear to represent a high volume alternative
fuel option.  Data suggest that the same characteristics that increase
the value of plastic scrap as an alternative fuel (e.g., high energy
value) also increase its value as an input to recycled products, because
it avoids the expense and raw material costs associated with virgin
plastic.  Anecdotally, however, several examples of cement kilns,
boilers, and other incinerators using plastic as a fuel source exist:

A cement kiln in Westport, New Zealand, experimented with sourcing scrap
from plastic manufacturers in 2006 (Plastics New Zealand 2006, p.1).

A consultant with expertise in environmental regulatory compliance
reports that plastic scrap from pharmaceutical packaging and diaper
manufacturing scrap have been or are considered usable in cement kilns
(Gossman 2007).

A Holcim representative reports that the company uses off-spec plastic
products in its cement kilns (Guerra 2008).  The company also in some
cases obtains plastics from recyclers who handle MSW and commercial
waste.

Dynegy Midwest Generation was reported to burn more than 500 tons of
polyurethane scrap and other materials per day in engineered fuels to
generate electricity.  According to Dynegy's estimates, for each ton of
coal displaced by polyurethane scrap, there is a reduction of more than
eight pounds of SO2 emissions.  (Center for the Polyurethanes Industry
2007.)

KeLa Energy, LLC, has a patent pending binding process to create
synthetic coal-based engineered fuels using readily available waste
plastics and plastic composites, including post consumer carpet, to bind
waste coal fines.  Biomass may also be included in the binder system. 
The KeLa synfuel produces lower SO2 and NOx emissions than does coal. 
The engineered fuel has been tested in industrial boilers and work is
ongoing to allow its use in utility boilers.  (KeLa Energy press
release, 2007). 

Because it is a refined hydrocarbon material, plastic scrap is a
high-value alternative energy source.  However, plastics from some
sources may be contaminated in ways that limit their value as fuel.  For
example, mixed plastics may include PVC, and the presence of significant
levels of heavy metals (e.g., e-waste) make certain types of plastic
scrap unfavorable for use as a fuel.

Non-Fuel Scrap Plastic Uses: The vast majority of scrap plastic is mixed
with virgin plastic of the same type and reused in the same or a similar
manufacturing process.  This process is called “regrinding.” 
Numerous other products are made from “downcycled plastic.” The
American Chemistry Council reports (ACC 2008d):

Recycled PET can be used in new food and beverage bottles (i.e.,
“closed loop” recycling) and “downcycled” into deli trays,
carpets, clothing, and automobile parts.

Recycled HDPE can become bottles for laundry products and motor oil,
recycling bins, agricultural pipe, bags, garden edging, decking and
plastic lumber.

Recycled vinyl can become playground equipment, flooring tiles, film,
and air bubble cushioning.

Recycled LDPE can be used to manufacture bags, compost bins, and plastic
lumber.

Recycled PP can be used in automobile parts including battery casings,
textiles, industrial fibers, and films used for bulk packaging.

Recycled PS can be used in products including office accessories, garden
nursery supplies, and protective package cushioning.

(3) Quantities of Scrap Plastics Landfilled:  Due to the efficiency with
which post-industrial plastic scrap can be recycled and the robust
market for plastic scrap, it does not appear that significant volumes of
post-industrial plastic scrap end up in landfills. An exception may be
off-spec products with multiple materials, although data are not readily
available to quantify this.

(4)	Quantities of Scrap Plastics Stockpiled/stored: Data are not readily
available on the stockpiling or storage of plastic scrap, but because
there is no restriction on disposal, it is likely that most discarded
plastic is disposed of in municipal or other non-hazardous landfills. 
It is possible that private stockpiles of plastic exist, but given the
high market prices for scrap plastics at this time it is not likely to
be a widespread practice.

4.	Management and Combustion Processes for Scrap Plastics

Types of Units Using Plastic Scrap as a Fuel: As explained above,
combustion of post-industrial scrap plastic appears to be common in the
cement industry.  We are unable to find evidence of wide-spread
combustion of post-industrial scrap plastic in the United States by
other industrial furnaces or boilers, beyond the examples noted above.. 

Supply/Processing Chain for Plastic Scrap: As described earlier, a
significant portion of plastic scrap is reworked into the production
process (i.e., recycled internally).  In this case, no transportation is
necessary.  Off-spec materials used as fuel appear to be transferred
directly from the producer to the combustion unit or fuel blender, where
they are typically ground or shredded prior to combustion.  For
post-consumer (MSW) plastic, the process is somewhat different. 
Material is collected and sorted by municipal recycling facilities
(MRFs) or private sector recycling operations into different common
types of plastic such as PET and HDPE, and in many cases some
decontamination also takes place prior to baling the product to sell as
scrap.

Processing Scrap Plastic for Fuel Applications:  

	In a mass burn furnace, plastic scrap could be combusted with no
further processing. In an refuse-derived fuel (RDF) facility and in most
cement kilns and boilers, scrap is shredded prior to combustion and
mixed with other fuel sources to provide a consistent fuel stream. 
Because industrial scrap plastic is typically uncontaminated and of a
single type, it is unlikely that facilities with industrial boilers or
kilns would need to clean the plastic prior to combustion.

Changes to Increase Use in Combustion:  Post-industrial plastic scrap is
already well-suited to combustion due to the high energy content and
uncontaminated nature of most of this material.  From the limited data
available, it appears that use of post-industrial plastic scrap as fuel
is not more widespread due to competing uses as an input into new
plastic product manufacturing.

State status of Scrap Plastic use as Fuel:  

	At this stage we have not identified any states that have approved use
of scrap plastics as fuel, but we have not performed an exhaustive
investigation of state activities and regulations.

5.	 Scrap Plastic Composition and Impacts

Composition of Scrap Plastic

	Scrap plastic has a high energy content ranging from 8,250 to 19,000
Btu per pound (EIA 2008). This can compare favorably with coal at 10,300
Btu/pound (EPA 2008a).  Non-halogenated plastics are composed primarily
of hydrocarbons with the addition of a wide variety of possible
additives (ACC 2008b).  PVC contains a substantial amount of chlorine.

 

Exhibit 4:  Heating Value for Common Plastics

Plastic Type	Btu/Lb.

PP	19,000

PS	17,800

LDPE/LLDPE	12,050

PET	10,250

Other	10,250

HDPE	9,500

PVC	8,250

Source:

EIA 2008

Impact Information

Criteria Pollutants and Hazardous Air Pollutants:  Although several
studies have been conducted on the criteria pollutant and hazardous air
pollutant (HAP) emissions associated with combustion of plastics, most
of these studies examine fuels that are a combination of plastics and
other materials, especially MSW.  Therefore, these studies do not
isolate the criteria pollutant or HAP emissions associated with scrap
plastics alone.  Nonetheless, uncontaminated scrap plastics tend to be
purified petrochemicals and potentially emit lower levels of pollutants
than combustion of other fossil fuels. 

Additional Avoided Impacts: In addition to other air emissions
associated directly with combustion, use of scrap plastics as a
replacement for traditional primary fuels may eliminate the
environmental impacts associated with extraction and processing of the
traditional fuels.  Note that this assumes that the scrap plastic used
as fuel is not economically recyclable.  Exhibit 6 lists the quantities
of cradle-to-gate emissions for these fuels based on typical processes
in the United States in the late 1990s.

Exhibit 6:  Emissions from Extraction and Processing of Traditional
Fuels

Pollutant	Coal	Distillate Fuel Oil	Residual Fuel Oil	Wood	Natural Gas

	-------------------- Lb./MMBtu -----------------

Criteria Pollutants

PM2.5	-	-	-	-	-

PM10	-	-	-	-	-

PM, unspecified	0.246	0.012	0.012	6.67x10-4	0.004

NOx	0.022	0.061	0.062	0.08	0.117

VOCs	0.008	0.361	0.365	-	0.515

SOx	0.022	0.186	0.187	0.003	1.913

CO	0.017	0.046	0.046	0.022	0.223

Pb	2.60x10-7	1.01x10-6	1.00x10-6	-	2.72x10-7

Hg	8.17x10-8	1.87x10-7	1.87x10-7	-	7.18x10-8

Source:

Franklin Associates 1998.

Note:

“-” signifies data not available; may equal zero.

The emission information presented in this table is derived from Life
Cycle Inventory (LCI) data, as compiled by Franklin Associates.   LCI
data identifies and quantifies resource inputs, energy requirements, and
releases to the air, water, and land for each step in the manufacture of
a product or process, from the extraction of the raw materials to
ultimate disposal. The LCI can be used to identify those system
components or life cycle steps that are the main contributors to
environmental burdens such as energy use, solid waste, and atmospheric
and waterborne emissions.  Uncertainty in an LCI is due to the
cumulative effects of input uncertainties and data variability.  

There are several life cycle inventory databases available in the U.S.
and Europe.  For this paper, we applied the most readily available LCI
database that was most consistent with the materials and uses examined.
These LCI data rely on system boundaries as defined by Franklin
Associates, as described in the documentation for this database,
available at:   HYPERLINK
"http://www.pre.nl/download/manuals/DatabaseManualFranklinUS98.pdf" 
http://www.pre.nl/download/manuals/DatabaseManualFranklinUS98.pdf .  

Cost Impacts: A Holcim Group Ltd. representative reports that in most or
all cases, Holcim is paid by manufacturers to take their plastic scrap. 
This arrangement often represents a cost savings to generators due to
avoided disposal, although in some cases manufacturers are willing to
pay a premium over other options to see their plastic scrap used for
productive purposes (Guerra 2008).

Finally, note that, while scrap plastic represents a high-quality fuel
source, at this time post-industrial scrap plastic appears to be more
valuable as recycled products.  As energy prices rise, making plastic a
more attractive fuel source, the prices of virgin plastic also rise,
resulting in increased emphasis on recycling.  However, for plastics
that are difficult or impossible to recycle economically, combustion of
scrap plastic, particularly by cement kilns, is increasingly attractive
both as a cost savings opportunity for companies, and also as an
opportunity to ensure that they are optimizing their materials
management strategies to recover the value of their materials.

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Scrap Plastics

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