Pollution Reduction Opportunity Evaluation
(PROE)
for Degreasers
State of New Jersey
Department of Environmental Protection
Office of Pollution Prevention and Right to Know
Table of Contents
Section
Page Number
1.0
Purpose of the PROE
3
2.0
Types of Degreasers
3
3.0
Pollution Reduction Opportunities
4
4.0
Questions to Ask and Decision Tree
5
5.0
Case Studies
7
6.0
Benefits of the Pollution Reduction method
9
7.0
Definitions
9
8.0
References
10
9.0
Contact Information
10
2
1.0
Purpose of the PROE Report
The Pollution Reduction Opportunity Evaluation (PROE) report identifies alternative methods to
reduce releases to the environment. It is a tool to facilitate discussions between regulators and
the regulated in order to implement pollution reduction methods in areas where there are
potential health concerns. The goal of the PROE program is to promote pollution prevention,
which is reducing or eliminating the need for hazardous substances per unit of product, or
reducing or eliminating the generation of hazardous substances where they are generated within
a process. This report identifies methods that can be used by a specific industry in order to make
measurable reductions in the amount of pollutants generated or discharged by the facility. There
are five Pollution Prevention Categories:
1. Input Substitution: Switch from a hazardous input to a non-hazardous one.
2. Product Reformulation: Alter the product, but not necessarily its function, so it requires less
hazardous substance.
3. Efficiency Improvement: Change production processes so they use necessary hazardous
substances more efficiently.
4. In-Process Recycling: Send hazardous materials back into a process, directly.
5. Housekeeping: Find fugitive leaks, prevent spills, control losses from tanks, etc.
The benefits of implementing the recommendations in the PROE report may include fewer
requirements in permits, exemptions from reporting such as Community Right to Know and the
Release and Pollution Prevention Reporting, and less inspection oversight. This benefits not
only the environment but also the industry since there can be substantial cost savings in pollution
prevention.
2.0
Types of Degreasing Operations
A degreaser is a cleaning machine used to physically remove soils from the surface of materials.
There are two types of vapor degreasers. One is a vapor immersion unit, which usually has two
solvent-filled sumps (the boil sump and the cold sump, which is filled with clean, distilled
condensate solvent and is often used for rinsing). The other type of degreaser is a vapor/spray
unit in which the solvent is boiled in the very bottom of a one-sump degreaser. A perforated
metal stand is just above the boiling solvent and a metal basket filled with dirty parts is usually
placed on this stand. The basket or parts are not immersed in solvent. Instead the vapor made by
the boiling solvent encompasses the parts completely and removes the oils and soils. The oils
and soils, now diluted into the condensing liquid, will drip back into the boiling solvent below.
There is a manual spray wand, which is sprayed under the cooling coils directly on hard-toremove soil (Murphy, 2000, ¶ 1).
Near the top of either type of degreaser is a set of cooling coils that catches the vapor before it
escapes from the unit. The vapor cools and condenses back to its liquid form, flows back to a
clean condensate tank and finally goes back to the boil sump or the rinse tank.
(Murphy, 2000, ¶ 2)
Cold Cleaning is the process of removing contaminants from the surface of metal parts at room
temperature. The parts are sprayed, brushed, flushed, or immersed and soaked into a cold
3
cleaner (typically a spray sink or a dip tank) containing a non-boiling solvent degreaser (ICF,
2004, Box 1-1).
Open Top Vapor Degreasing is an immersed cleaning process using hot vapors and liquid
solvent in a boiling sump to remove soils, particularly oils, greases and waxes. An open-top
vapor degreaser consists of an open steel tank with a heated solvent reservoir, usually referred to
as a sump, and a cooling zone near the top. The sump is heated to boil the solvent and generate a
solvent vapor blanket that covers the liquid solvent in the tank. The solvent vapor condenses
when it reaches the cooling zone; this clean liquid solvent condensate flows to rinse tanks which
overflow back to the boil sump (ICF, 2004, Box 1-1).
Conveyorized Vapor Degreasing is a less frequently used cleaning method involving the use of
large, enclosed mechanical systems that handle a large workload capacity. Also known as in-line
vapor degreasers, these units operate similarly to open top vapor degreasers with the exception
that parts are continuously moved into and out of the cleaning zone (vapor or solvent liquid) and
rinse zones on a conveyor belt (ICF, 2004, Box 1-1).
Aerosol Solvent Cleaning is a specialized spot cleaning process for confined areas of machinery
and parts. Contrary to other equipment and processes where the part being cleaned is immersed
into a cleaning tank, aerosol solvents are contained typically in an aerosol can and are dispensed
onto the parts being cleaned. A spray tube inserted into the valve of the can or a flexible tube
ending in a small brush assists in the discharge of the cleaning solvent. This process is 100
percent emissive in nature with essentially no reuse possible (ICF, 2004, Box 1-1).
Aqueous Cleaners range from pure water to exotic combinations of water, detergents,
saponifiers, surfactants, corrosion inhibitors and other additives. When combined with heat,
pressure, agitation, etc., they can be an effective alternative for most cleaning applications
(Carter, 1999, Aqueous Cleaner section, para. 1).
Terpenes are chemical compounds extracted from the bark of trees or citrus fruit skins. They
have been used in household cleaners, pharmaceuticals, deodorizers and other commercial
products (Carter, 1999, Semi-Aqueous Cleaner section, para. 1).
Mechanical Cleaning uses materials such as sand, plastic beads, glass beads, steel shot, walnut
shells, frozen CO2 cereal, baking soda, etc., to clean various substrates (Carter, 1999,
Mechanical Cleaning section, para. 1).
3.0
Pollution Reduction Opportunities
There are a number of options available for facilities that are looking to switch to a less
hazardous cleaning solvent. However, there is no “one size fits all” replacement for solvents in
any cleaning operation. Some of the alternatives such as aqueous or semi-aqueous processes
may require new equipment or the addition of multiple cleaning steps. Other options such as
terpenes, alcohols, and petroleum distillates may have disposal concerns. In addition, a facility
has to consider what types of oils and soils need to be removed from the object being cleaned
before choosing an alternative cleaning method to ensure that the product will meet quality
specifications. This is because the make-up of the oils and its chemical composition can
4
influence what type of cleaner used. For example, halogenated oils, in which a halogen ion (e.g.,
fluorine, chlorine, bromine, or iodine) has been attached, are removed using halogenated
solvents, whereas, non-halogenated oils are removed using non-halogenated solvents.
There are a number of resources available such as the Office of Pollution Prevention and Right to
Know, the New Jersey Program for Manufacturing Excellence and internet web sites that can
help determine which alternative cleaning process is best for a given situation. Listed below are
some common halogenated solvent cleaners, which are regulated by MACT requirements, and
some web sites that might be helpful in determining alternative methods to using halogenated
solvent cleaners. Also included are some questions that can be asked about the product being
cleaned and the quality of the finished product. Lastly included are two case studies of facilities
in New Jersey that have successfully switched from halogenated solvents to a less hazardous
cleaner.
Common Halogenated Solvent Cleaners
Carbon Tetrachloride
Chloroform
Perchloroethylene
1,1,1 Trichloroethane
Trichloroethylene
Methylene Chloride
Carcinogen, Ozone Depleting
Carcinogen
Carcinogen
Ozone Depleting
Carcinogen
Carcinogen
Use and production banned
Production banned
Alternative Solvent Resources
Safe Solvent Alternatives Guide: http://clean.rti.org
Waste Reduction Resource Center: http://wrrc.p2pays.org/
Surface Solutions Laboratory:
www.cleanersolutions.org/SimpleSolutions
Halogenated Solvent
1,1,1 Trichloroethane
1,1,1 Trichloroethane and
Trichloroethylene
4.0
1.
2.
3.
4.
5.
Alternative
n-Propyl Bromide
HFE-72DA
Examples
See Case Study 1
See Case Study 2
Questions to Ask and Decision Tree to Guide Evaluation
What is being cleaned?
What is being removed?
How are soils removed? Can the process be improved?
Do you have to meet military or other specifications?
What kind of oils do you use? Can you use a different kind?
5
Decision Tree to Guide Evaluation
No
Discontinue
Degreasing
Do parts need to be
cleaned?
Yes
No
Evaluate Oil
Usage
Is the amount of oil
applied controlled?
Yes
Do the parts have to
be cleaned to meet
specifications?
Yes
Consider
Process
Modification
No
No
Evaluate
Alternatives
(See Section
3.0)
Have solvent
substitution options
been considered?
Yes
Are oils and solvents
recycled?
No
Evaluate
Recycling
Options
Yes
Implement
Feasible Changes
6
5.0
Case Studies
Case Study #1
Durex, Inc.
Durex, Inc. (Durex) is a 120-employee manufacturing company located in Union, New Jersey.
The major processes at the facility include metal stamping, sheet metal fabrication, assembly and
finished product. Durex operates an open-top vapor degreaser, equipped with a closed cover and
a freeboard chiller, to remove oils from metal parts.
Prior to1998, the main solvent used in the degreaser was 1,1,1-Trichloroethane. However, new
regulations, safety concerns and cost prompted Durex to investigate other options. Their first
option, a non-HAP solvent called Techtride NPB DG which consist of n-propyl bromide (CAS
106-94-5), 1,2 Butylene Oxide (CAS 106-88-7) and 1,3-Dioxolane (CAS 646-06-0) was found to
clean as well as 1,1,1-Trichloroethane. Also, they found that this non-HAP solvent could be
used in their existing equipment.
Durex decided to use Techtride NPB DG, manufactured by Parts Cleaning Technologies (PCT),
in their degreasing unit. The driving forces to make the switch were the environmental, safety
and cost aspects. These included no emissions to the atmosphere, less harmful exposure to
employees, and reduced purchasing costs. Durex also implemented other pollution prevention
methods in their degreasing unit, which includes collecting the oil after it is removed from the
metal parts and shipping it back to the manufacturer, and recycling Techtride NPB DG back into
the degreaser unit. As a result, Durex does not have any waste shipped off-site from their
degreasing operation.
Below is a graph from the Release and Pollution Prevention Reports (RPPR) that show the
reduction of 1,1,1 Trichloroethane through the years 1994 to 1998. After 1998, Durex, Inc.
stopped reporting this chemical completely.
NPO (Lbs/yr)
1,1,1-TRICHLOROETHANE
7
1998
1997
1996
1995
CalculatedNPO
1994
90,000.00
80,000.00
70,000.00
60,000.00
50,000.00
40,000.00
30,000.00
20,000.00
10,000.00
0
Case Study #2
Bihler of America, Inc.
Bihler of America, Inc. (Bihler) is a 150-employee manufacturing company located in Alpha,
New Jersey. Bihler used 1,1,1-Trichloroethane and Trichloroethylene up to the mid 1990’s,
where their primary product at the time was slide doors for computer discs. As their product line
changed, they used the opportunity to change their cleaning processes from those using HAPs.
Since the mid 90's Bihler has continued to look for improvements in its cleaning processes and
has used Abzol , (N-Propyl Bromide), 3M's HFE, water and detergent washes, and pressurize hot
water.
Abzol had some maintenance and employee exposure issues. Essentially if it was not monitored
and changed properly, it could turn acidic. HFE was expensive, but was a non-HAP with
minimal VOC (Volatile Organic Compounds) and with no ozone depleting chemicals.
Water and detergent did the job, but because of the detergent there were still pollution and waste
removal issues. Anything other than air and water vapor emitted from a stack is a pollutant.
Bihler now has one degreaser, which uses HFE 72DA, and several pressurized hot water
cleaners. Bihler operates an open-top vapor degreaser with a passive control system using
refrigeration to limit emissions and employee exposure. A mechanical arm lowers the basket
into and out of the system and once the parts are degreased, the basket is held in the refrigerated
zone so that all VOCs condense back into the tank. The used solvent is changed out periodically
and returned to the supplier.
With the water cleaning systems, the dirty, oil- contaminated water first goes through a filtering
system and then to an oil/water separator. The water is then recirculated back to the cleaning
system and reused. Some water is evaporated as part of the process and replaced and the
separated oils are shipped off-site as petroleum waste.
The major products currently produced at this facility include surgical needles (unfinished),
electrical supplies (outlets, switches) and small metal fabricated parts. Bihler uses HFE-72DA in
their degreaser, manufactured by 3M, which consist of 1,2-trans-dichloroethylene (CAS 156-605), ethyl nonafluoroisobutyl ether (CAS 163702-06-5), ethyl nonafluorobutyl ether (CAS
163702-05-4), methyl nonafluoroisobutyl ether (CAS 163702-08-7), methyl nonafluorobutyl
ethyl ether (CAS 163702-07-6), and isopropyl alcohol (CAS 67-63-0). The HFE-72DA was an
expensive choice for Bihler, but it was determined that the switch was worth it, not only from an
environmental perspective, but because there are reduced permitting requirements, storage and
handling costs, and permit fees.
In addition to the solvent substitution methods described above, Bihler conducts an evaluation of
the products to be cleaned. Bihler asks key up-front questions of themselves and their clients
such as: “How clean does the product need to be?" or " What standard for cleanliness applies?"
and “What is the most efficient oil application?” Bihler realizes that some products do not have
to be cleaned to the highest quality because these products will be cleaned or undergo further
processing by their clients. Also, Bihler instituted a computerized system to control the amount
8
of oil put onto the metal parts. These up-front efforts not only reduce cleaning efforts, but also
minimize oil consumption and emissions issues for a more cost efficient operation.
Bihler has been able to address environmental improvements because the management
recognizes the relationship that good environmental and safety efforts have on the financial
bottom line. Additional pro-environmental initiatives at Bihler include using low energy
lighting, automatic sensors that dim or turn off warehouse lighting during periods of inactivity,
and using variable frequency drives on air compressors.
Below is a graph from the Release and Pollution Prevention Reports (RPPR) that show the
reduction of 1,1,1 Trichloroethane and Trichloroethylene through the years 1994 to 1996. After
1996, Bihler stopped reporting these chemicals completely.
NPO (Lbs/yr)
140,000.00
120,000.00
100,000.00
80,000.00
60,000.00
40,000.00
20,000.00
TRICHLOROETHYLENE
6.0







7.0
1997
1996
1995
CalculatedNPO
1994
0
1,1,1-TRICHLOROETHANE
Benefits of the Pollution Reduction method
Comply with federal and state regulations
Eliminate solvent storage and handling
Eliminate potential for accidental releases
Create safer working conditions
Eliminate air regulation compliance costs
Eliminate solvent purchase and disposal costs
Eliminate emissions of ozone-depleting, global warming, and hazardous compounds
Definitions
Applicable VOC: any volatile organic compound (VOC) which has a vapor pressure or sum of
partial pressures of organic substances of 0.02 pounds per square inch (1.0 millimeters of
mercury) absolute or greater at standard conditions.
9
Consume: to change or alter the molecular structure of a hazardous substance within a
production process.
Hazardous Air Pollutant (HAP) solvent: any hydrocarbon compound listed in the Clean Air
Act, Title III, section 112, subsection b. (42 USC 7412).
Nonproduct Output (NPO): all hazardous substances or hazardous wastes that are generated
prior to storage, out-of-process recycling, treatment, control or disposal, and that are not intended
for use as a product. NPO includes fugitive releases.
Soils: contaminants that are removed from the parts being cleaned. Soils include, but are not
limited to grease, oils, waxes, metal chips, carbon deposits, fluxes and tars.
8.0
References
New Jersey Department of Environmental Protection (1997). State of the Art (SOTA) Manual
for Degreasers and Other Solvent Based Metal Surface Cleaners, 3.6-3 – 3.6-4.
ICF Consulting (2004). The U.S. Solvent Cleaning Industry and the Transition to Non Ozone
Depleting Substances, Retrieved December 2005 from United States Environmental Protection
Agency Website: http://www.epa.gov/spdpublc/snap/solvents/EPASolventMarketReport.pdf
New Jersey Department of Environmental Protection (1995). Industrial Pollution Prevention
Planning, Trenton, NJ, 2nd Ed, 9.
Carter, B. (1999). Solvents - The Alternatives. Retrieved December 2005, from North Carolina
Department of Environment and Natural Resources Website:
http://www.p2pays.org/ref/01/00023.htm
Murphy, R.P. (2000). How a Vapor Degreaser Works. Retrieved December 2005 from
Degreasing Devices Co. Website:
http://www.users.interport.net/r/o/rod.ma.ultranet/www.degreasingdevices.com/ebook.htm
9.0
Contact Information
For more information on the PROE Report or the case studies, contact the Office of
Pollution Prevention and Right to Know at 609-777-0518.
10