EXTENSION OF METAL WORKING FLUID SERVICE LIFE
|Overview:||Generation of waste
metal-working fluids can be minimized by extending the useful life of the
fluids. Metal-working fluid life is a function of various factors
including: type of metal working operation, type/quality of fluid used,
housekeeping practices, contamination, bacterial contamination, and water
Spent metal-cutting fluids may be considered hazardous wastes due to the products’ formulation or by absorbing contaminants through metal working operations. Under 40 CFR Part 279, Used Oil Management Standards, used oil is defined as oil refined from crude (or any synthetic oil) used as a lubricating, hydraulic, or heat transfer fluid that has become contaminated through use. Coolants may be managed under these regulatory provisions and recycled as opposed to disposed. Extending the fluid life by maintaining its cleanliness is a practical means of reducing a hazardous waste stream.
Modular systems are available for on-site, batch recycling of metal working fluids. These systems clean the fluids by removing solids, bacteria, and tramp oil contaminants. These systems may incorporate filtration, centrifugation, pasteurization, oil skimming, and/or coalescence processing steps. Water or fluid concentrate may be added to the reclaimed fluid to adjust the fluid concentration to the desired level. The fluids are then returned to the machine sump(s).
Milacron markets modular systems for collection, treatment, and recycling of metal working fluids. One such unit was used for short time at the Naval Shipyard in Portsmouth, New Hampshire. The capital costs for a fluid collection device and recycle module would start at around $40,000.
An alternative to purchase, operation, and maintenance of recycling equipment by the shop is the use of mobile recycling services, such as Fluid Recycling Services. These services utilize similar processing steps to those described above to treat metal working fluids on-site on a periodic basis. There is typically a minimum charge per visit plus a rate per gallon of fluid treated.
For shops that generate less than 25 tons/yr. of waste cutting oil, or less than 45 tons/yr. of waste soluble oil machine coolant, a mobile fluid recycling service would probably be the preferred arrangement. For shops that generate larger amounts of waste metal working fluids, purchase of in-house recycling equipment should be considered. For either option, the economics of recycling metal working fluids are improved by minimizing the number of different metal working fluids used in one shop.
of cutting oil may allow the used oil to fall under the less stringent
regulations of 40 CFR 279 as opposed to the hazardous waste regulations
in 40 CFR 260 through 268. In addition, under 40 CFR 261.5,
generators that recycle their used oil and manage it under 40 CFR 279
do not have to count the used oil into their monthly totals of hazardous waste
generated. This may help facilities to meet the requirements of waste reduction
under RCRA, 40 CFR 262 and Executive Order (EO) 13148. The
decrease in the quantity of hazardous waste generated monthly may also help a
facility reduce their generator status and lessen the amount of
regulations (i.e. recordkeeping, reporting, inspections, transportation,
accumulation time, emergency prevention and preparedness, emergency
response) they are required to comply with under RCRA, 40 CFR 262.
Recycling of used oil generally requires a facility to store large
quantities of used oil on site. A Spill Prevention, Control and
Countermeasure Plan is required to be developed and implemented under
40 CFR 112 for facilities that store certain amounts of oil on
site. Finally, due to the reduced amounts of cutting oil stored on
site, a facility may decrease the likelihood of meeting reporting
thresholds under SARA Title III (40 CFR 300, 355, 370, and 372).
The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved.
|Materials Compatibility:||No materials
compatibility issues have been identified.
|Safety and Health:||Mild skin and
eye irritation effects are associated with these compounds. Personal
protective equipment should be used. Consult your local industrial health
specialist, your local health and safety personnel, and the appropriate
MSDS prior to implementing this technology.
|Economic Analysis:||The following example is
for a facility that generates a fairly large quantity of spent cutting
fluid (3,000 gallons per year). Most facilities will generate less than
this amount thus extending the potential payback period. For smaller
shops, off-site recycling services may be more cost effective. The cost
for fresh cutting fluid is based on vendor information. An economic
analysis comparing on-site cutting fluid recycling versus disposal can be
found on datasheet 6-I-8 Cutting Fluid Recycler.
Table 1. Annual Cost Comparison for On-Site Recycling or Off-Site Recycling of Used Cutting Fluid
Economic Analysis Summary:
Here to view an Active Spreadsheet for this Economic Analysis and
Enter Your Own Values.
authority for making process changes should always be sought and obtained prior to
procuring or implementing any of the technologies identified herein.
|Points of Contact:||For more information|
|Vendors:||This is not meant to be a complete
list, as there are other manufacturers of this type of
CECOR Inc. Waterlink Inc. Master Chemical Corporation
Master Chemical Corporation
|Sources:||Mr. Cliff Myers, Defense Supply Center Richmond, March 1999.|