Materials Characterization Paper In Support of the Proposed Rulemaking: Identification of Nonhazardous Secondary Mate rials That Are Solid Waste Spent Solvents and Related Materials

March 18, 2010

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1. Definition of Spent Solvents

A solvent is a material used to dissolve or d ilute another substance. Examples of solvent use include degreasing, cleaning, and fabric scouring, use as diluents, extractants, and reaction and synthesis media. A spent solvent is a solvent that has been used at least once and cannot be used again for its original purpose wit hout being processed, due to contam ination during its use. This analysis addresses only solvents th at: 1) have potential fuel value (i.e., organic solvents), and 2) are not considered hazardous under RCRA. Spec ifically, this paper targets non-hazardous, nonhalogenated, solvents. Non-ha logenated solvents include a variety of organic chemicals (hydrocarbons, alcohols, ketones, esters, etc).

2. Annual Quantities of Spent Solvents Generated and Used

(1) Sectors that generate spent solvents:

• A wide range of non-hazardous spent solvents are generated by a large number of

industries. Generators of spent solvents can include i ndustries that use solvents, industries that recycle or process spent so lvents from other sources, and, in some cases, industries that manufacture solven ts. Facilities in th e following NAICS industry sectors focus specifically on the manufacture or management of solvents: 325998 – Recycling services for degreasin g solvents (e.g., engine, machinery) manufacturing; 325132 – Solvent dyes manufacturing; 324110 – Solvents made in petroleum refineries; and 811111 – Auto motive repair and replacement shops.

• Solvents are typically used in the follow ing industries and applications: coatings, cleaners, inks, adhesives, pharmaceutical s, agricultural and food uses, personal care, automotive, microelectronics, a nd aerosol products (American Chemistry Council 2008).

(2) Quantities and prices of spent solvents generated:

• Due to the wide variety of solvents produced and used, it is difficult to characterize the quantity or prices of spent organic non-hazardous solvents generated in the U.S. Only a fraction of all so lvents produced return to the market as spent solvents; many are recycled a nd reused on site by generators. Total annual production of solvents exceeds 10 billion pounds (5 million tons) per year (Paint and Coatings Industr y 2006). This suggests that the total qu antity of solvents that require replacement could also be roughly five million tons per year.Spent Solvents and Related Materials

• The limited information available on markets for spent solvents focuses on hazardous solvents; thes e are commonly used as fuel, and they are “priced” to be less expensive to the generator than the avoided cost of hazardous waste disposal, which can range from $0.41 to $2.13 pe r gallon (Environmental Technology Council 2004).

(3) Trends in generation of spent solvents:

• Information on trends in generation of spen t solvents is difficult to assemble given the range of products and management op tions. National demand for solvents is expected to rise by one percent a ye ar to 12.5 billion pounds in 2010 (Paint and Coatings Industry 2006). However, as in terest in recycling, reuse, and waste minimization increases, and the costs of reuse decrease, this projection may not

hold.

3. Uses of Spent Solvents

(1) Combustion uses of spent solvents:

• Solvents with sufficient calorific value and minimal contamination can be readily used as fuel in a range of boilers, furnaces , and kilns. However, readily available information suggests that non-hazardous solvents do not represent a significant

alternative fuel source.

• Portland Cement Association data indi cated that the BTU value per pound of spent solvent varies due to the wide va riety of solvent types (Portland Cement Association 2007).

• Solvents that are considered hazardous under RCRA frequently have fuel values

that are similar to coal. Hazardous wast e, as estimated by the Assessment of the Potential Costs, Benefits, & Other Imp acts of the Hazardous Waste Combustion MACT Final Rule Standards, and th e Economic Analysis for the Proposed Emission Comparable Fuel rule (based on the information contained in the hazardous waste constituent survey), has a heating value between 12,200 and 13,500 Btu per pound. In fact, a number of these solvents appear to meet the definition of hazardous waste because they are characteristic for ignitability, suggesting that there is a strong correl ation between hazardous solvents and high fuel-value solvents. This may suggest that non-hazardous solv ents are typically less valuable as a fuel source, but the va riation among solvents makes it difficult to draw any specific conclusion.

(2) Non-combustion uses of spent solvents:

• Most spent solvents can be reprocessed and recycled for use again in their original form. Facilities that produce spent solv ents may choose to install recycling equipment in an effort to cut costs on virgin solvent purchases (see, for example, Ohio EPA 2004; and NSBDCBEP). It is di fficult to estimate the quantities of nonhazardous spent solvents disposed or kept in storage because they originate in many locations, and are likely managed in a number of different ways. It appears, however, that recycling is a viable op tion for a significant percentage of nonhazardous solvents.

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4. Management and Combustion Processes

(1) Types of units using spent solvents

• It is possible that some non-hazardous, orga nic, solvents may have Btu values that would give them value as a fuel sour ce. Hazardous solvents, whose generation and management is tracked in the Biennial report, are burned as fuel in a variety of liquid-fuel industrial boilers and cement kilns.

• One limitation concerning burning solvents may be the design of combustion equipment. Bullard (2007) notes that boiler and burner manufacturers and other companies that support commercial an d industrial boilers have only limited experience with burning hazardous or non-hazardous waste solvents. These boiler/burner supportive industries are more familiar and more interested in working on projects involving traditional fuel s like natural gas and distillate, since this is the fuel overwhelmingly in use in industry (Bullard 2007).

• Cement kilns are experienced at burning hazardous waste solvents, along with a range of other liquid wastes. However, an industry contact noted that EPA’s introduction of the exclusion rules in the 1990s that removed materials with high Btu values, when used as fuels, from the definition of solid waste, have resulted in more energy recovery from solvents on-site at manufacturers; as a result, solvents

have diminished as a fuel source in the cement industry (Guerra 2008).

• An EPA document source concerning industry impact information of boilers suggests that some nonhazardous waste burn ing cement kilns use, among various other secondary fuels, spent lubricants and solvents (EPA 2 008b). These data are not sufficiently broken down to attribute any energy savings information to spent solvents specifically.

(2) Sourcing of spent solvents: Spent solvents originate in many locat ions, and a national- level collection and distribution system does not exist for all t ypes of solvents. However, census data indicates that recycling of solvents is wi despread. Recycling services for degreasing solvents (e.g., engine, machinery) manu facturing includes 1,188 facilities that are involved in the management of secondary so lvents. This does not address the on-site recycling and fuel recovery activitie s that take place at generators.

(3) Processing of spent solvents: In some cases, only minimal processing is required to reuse spent solvent on site, since it is not always necessary to have 100 percent purity (Ohio EPA 2004). Alternatively, some types of solvents ma y not be suitable for reuse even after significant processing (incl uding physical and chemical processes to remove impurities) and therefore must be manage d through an alternate method, including being used in a different process or sold to another company for use.

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(4) State regulatory status of spent solvents use as ingredient: At this stage, we have not identified a ny states that have sp ecifically granted a beneficial use designation for the use of spent solvents as fuel, but we have not performed an exhaustive investigation of state activities and regulations.

5. Commodity Composition and Impacts

(1) Composition of spent solvents: The composition of spent solvents can vary widely depending on the original chemical structure and the solvent, and the s ubstance with which it was first used. To

be useful as a non-hazardous fu el source, solvents must have carbon (i.e., be organic). However, other constituents are difficult to characterize because they are based largely on the specific pr ocess (e.g., cleaning producti on equipment) in which the solvent was originally used.

(2) Impacts of spent solvents use:

• Data from the Portland Cement Associat ion notes that the Btu value per pound of spent solvent varies (Portland Cement A ssociation 2007), but when it can be used as an alternative fuel, it offsets use of primary fuels.

• Benefits associated with use of spent solvents as fuel include avoided risks associated with disposal, cost savings associated wi th avoided disposal and recovery of energy, and the avoided e nvironmental impacts associated with production of energy from “virgin” non-renewable sources when solvents are

used instead. 1

• The specific lifecycle impacts of spent solven ts used as a fuel are not evaluated here because of uncertainties in lifecycle scenario development. For example, it is difficult to identify the fuel (Btu) value and emissions factors associated with a “typical” non-hazardous organi c solvent that is suitable for fuel. In addition, spent solvents may substitute for a variety of fu els; the choice of fu el often depends on location specific-factors such as the locati on of the combustor in relation to fuel supplies, and on the design of the specific combusti on unit. Avoided upstream impacts depend heavily on the specific fu el being displaced in the lifecycle

scenario.

1 With respect to the costs associated with beneficial use, cement kiln operators are generally required to enact performance testing and air permit modifications prior to using scrap tires and other alternative fuels. In addition, kilns may be required to install continuous emissions monitoring systems if they chose to burn scrap tires (EPA 2008a)

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References

Personal Communication with Erika Guerra, Holcim Ltd., August 26, 2008.

American Chemistry Council, “Solvents Industry Group: Solvents Explained.” 2008. Available at http://www.americanchemistr y.com/s_acc/sec_solvents .asp?CID=1483&DID=5586

Bullard, Jack L., P.E. “Determining the Technical Feasibility of Firing Waste Solvent in an Existing Industrial or

Commercial Boiler.” Continuing Engineering Education Journal . Article #0015. 2007. Available at: http://www.ceejpublishing .com/Articles/0015.htm

Environmental Technology Council, “May 2004 Incine rator and Landfill Cost Data,” 2004. Available at: http://www.etc.org/costcurvey8.cfm

Nevada Small Business Development Center Business Environmental Program (NSBDCBEP), “Solvent Recycling at Crumrine,” CS- FY9501018. Available at: www.nsbdcbep.org/pdf/case/Crumrine.pdf

Ohio EPA, “Onsite solvent recycling equipment,” Office of Pollution Prev ention. September 2004, Number 9. Available at: www.epa.state. oh.us/opp/solvents/fact9.pdf

Paint and Coatings Industry, “U.S. Solv ents Demand to Exceed 12 Billion Pounds in 2010,” July 1, 2006. Available at: http://www.pcimag.com/Articles/Industry_News/515aaeb98e85c010VgnVCM100000f932a8c0____

Portland Cement Association, “Beneficial Reuse of Ma terials in the Cement Manu facturing Process.” PCA R&D Serial No. 2868. p. 8. 2007.

United States Environmental Prot ection Agency, (E PA). 2008a, Cement Sector Trends in Beneficial Use of

Alternative Fuels and Raw Materials , October 2008

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United States Environmental Protection Agency (EPA). 2008b, “Identification of Nonhazardous Materials That are Solid Waste. EPA Exhibit 1: Preliminary Estimate of Total Non Hazardous Secondary Materials Used Annually in Boilers and Kilns. Sept. 24, 2008

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