Ajax  Loading... Please wait...

Types of Machine Coolant Disposal

Our Newsletter

Types of Machine Coolant Disposal

WARNING:  Do not take the following as being absolutely correct or as being all you need to know.   These were really good guidelines when I wrote them but laws change all the time.  In addition these are based on federal laws.   While most states and other governments follow federal laws many exceed them and / or have their own twists on them. 

Even with the best machine coolant management program, machine coolant will not last indefinitely and will eventually require disposal. Environmental regulations are making disposal increasingly difficult.  Generators are responsible for determining if a particular waste generated at their facility is hazardous or nonhazardous.  The waste material must be tested using standard methods or the generator must have sufficient knowledge about the waste to assess whether it is a hazardous waste.  View some of our articles in the Machine Coolant Filtration Index for more information on Machine Coolant Management and for more information on helping you cut costs on Disposal and recycling of Machine Coolant. 

Know whether your wastes and wastewaters are a dangerous waste.  Dissolved metals, chlorinated oils, and biocides are among the ingredients that can require machine coolant to be disposed as a dangerous waste.  Avoid chlorinated oils when possible.  Never mix other wastes such as solvents into machine coolants.  Even a small amount of a federally listed solvent can cause a whole container or tank of machine coolant to be a dangerous waste.  Call your local Ecology office for advice. 

Machine Coolant and Cleaner Disposal

Industrial wastes such as machine coolants and sump cleaners should never be disposed to a septic or storm system, or drywell. 

Oil-water emulsion machine coolants can often be chemically "split" to separate the oil from the water.  It may be more economical for you to discharge the water to the sewer and recycle the oil portion. 

Check with your local sewer utility before you discharge metalworking liquids to the sewer. 

Processing of a dangerous waste machine coolant for disposal must be done in accordance with regulations for treatment by dangerous waste generators (see Ecology publication #96412, Treatment by Generators). 

Following a hazardous / non-hazardous determination for the waste, an appropriate disposal alternative may be selected. Disposal costs may range anywhere from 25 to 50 cents per gallon for non hazardous waste up to several hundred dollars per drum for hazardous waste. Spent machine coolant that is determined to be hazardous must be disposed by an EPA permitted hazardous waste management company in accordance with applicable federal and state regulations. Selecting a certified hauler and treatment facility registered with the EPA is critical. 

Disposal Of Nonhazardous Fluid

If the waste fluid is determined to be nonhazardous, it may be hauled to a treatment facility or, following permission from local wastewater treatment plant authorities, discharged to a municipal sanitary sewer system for disposal. Spent fluid should never be discharged to a septic tank system or dumped on the ground. 

Nonhazardous fluid may also be pretreated on site prior to disposal. Treating or condensing water miscible fluids on site prior to disposal may reduce a shop's disposal costs and environmental liability. Techniques for on-site treatment include chemical treatment, ultra-filtration, and evaporation. Each process involves the removal of metal fines and other solid contaminants, concentrating the oil phase, and discharging the water phase to either the sanitary sewer or the atmosphere. The concentrated oil phase can be managed as a used oil and the solids may be disposed or reclaimed. 

Disposal And Pretreatment Alternatives available for non-hazardous water-miscible machine coolant. 

Contract Hauling and Disposal Services

Studies have shown that it may be cheaper to have small volumes of waste fluid (less than 200 gallons) hauled away by a waste management company for chemical treatment or incineration.

Many large machine shops opt for in-plant waste treatment, since contract hauling and disposal services become cost prohibitive with larger quantities of waste fluid. 

Chemical treatment

Chemical treatment is the addition of chemicals, which change the nature of the liquid waste. Simple chemical-treatment methods work well on some wastewater. Metalworking wastes are too complex for most treatment processes. Chemical treatment beyond pH control is generally not an option for small facilities. 

Ultrafiltration systems,

Ultrafiltration systems were created for the Metalworking industry to treat such wastes as used machine coolants, detergents, parts washing solutions, and other oily wastewaters. Strict environmental laws require proper treatment prior to discharge. Ultrafiltration systems provide effective treatment of this wastewater by separating the water from the oily waste. The quality of water is then ready for sewer disposal. The oily concentrate generated from ultrafiltration may be processed for oil recovery or incinerated. 

Ultrafiltration systems are usually better than chemical treatment, less expensive than incineration and contract hauling, are easily operated and space efficient. Units process from 100 to 300 gallons per day and cost from $5,000 to $13,000. 


As water miscible fluids are normally 90 to 95% water, evaporators can be used to remove the water from waste fluid, reducing the volume of waste requiring disposal. The advantages of evaporators include:

1.  Simple to operate.

2.  Use very little space.

3.  Type of fluid used (synthetic, semi synthetic, or soluble oil) is not critical. 

Evaporators are generally suitable for low volumes of waste due to the enormous amount of energy required to evaporate even a small volume of material. Evaporators are also labor intensive when it comes to cleaning the units. Evaporators may be a consideration when other treatment systems do not meet a shop's needs. 

Centrifuges can be used to remove particulates and tramp oil from waste fluid prior to disposal. However, centrifuges are expensive and other contaminant removal methods such as oil skimmers are more economical for small volumes of fluids. 

Disposal as wastewater

Following approval by local wastewater treatment authorities, it may be possible to dispose of small amounts of non-hazardous, spent machine coolant to the municipal sanitary sewer system. 

A Waste Management Program
We are not attorneys.  We believe this to be a good compliance plan but we do not take any responsibility for its use, misuse or anything else.  The laws change frequently.  Consult an attorney or other expert. 
Program Components
1.    A review of all MSDS sheets for compliance.
2.    A computer check of nine lists and 1,962 chemicals cited in 40 CFR
3.    A document showing matches or no matches.   
4.    An analysis of your used machine coolant done by a government certified laboratory.  
5.    An analysis that can serve as “An analysis of a typical batch” and may make testing of each batch unnecessary.
6.    A determination of the classification of the chrome component of your waste as required by law. 
7.    A review of classification options for your waste.
8.    A recommendation as to the best disposal option for your machine coolant. 
9.    References to the sections of federal law supporting these recommendations.
10.  A list of federal EPA offices and state offices for environmental matters.  
11.  A list of haulers and disposal companies. 


Classifying or characterizing your waste 

Step by step

1.  Gather MSDS sheets from everything that went into the machine coolant.

2.  Call waste disposal companies and tell them that you are taking bids to haul away ordinary grinding machine coolant wastes. 

3.  If they ask questions, just tell them that it is ordinary tool and saw grinding and that you have MSDS sheets for everything. 

Take the lowest bid from a reputable hauler. 

Finding a hauler.

1.  Ask other people in the same or similar industries for recommendations.

2.  Call the local city, state or Federal people and ask them for the name of businesses that do a really good job handling waste.   The government people cannot recommend a particular hauler.  They usually have some sort of a model business program or award.  They can tell you the name of businesses like yours, that do things well and then you can call those businesses to get the name of their haulers.  


This is very important because there is paperwork involved.  If the hauler does not do things properly you could be getting into even more trouble.  If the hauler takes your waste, dumps it in the woods illegally and then gets caught you can be held responsible for cleaning up the woods even if the hauler lied to you. 

There is generally a requirement you have to sign saying that you have taken measures to reduce waste.  It may be phrased as “waste reduction” or “minimize your waste stream” or something similar.  

There are several things you can do to easily and simply comply. 
1.  Use safe components.  
2.  Manage for long life.
3.  Filter and keep it clean.
4.  Keep it adjusted chemically.
5.  Separate the waste.
6.  Evaporate the wastewater. 


The requirement is that you take reasonable measures.   This is very good.  Some parts of some environmental laws require using the absolutely best technology without regard to cost.  

In this case implement the steps you think are appropriate and then add additional steps as you determine they are beneficial and / or cost effective. 

The government is different than industry.  This sounds simple but it is really important.   There are two big differences.  In the private sector people are very concerned with getting things done.  They are required to make decisions and then make those decisions work.  In the public sector the employees are hired to do what the law says they are supposed to do.  The best way to keep their jobs is to do what the law says and to avoid making any decision of their own. 

If you tell them you have hazardous waste then they will agree because that is the easiest and safest thing for them to do.  If you tell them that you have used grinding machine coolant and it is not hazardous waste then they will ask to see proof.   They are generally very willing to accept your decision if you can support your decision. 

If you tell them that you don’t know what is in it they will be required to treat it in the most thorough and therefore most expensive manner possible. 

When you are asked what is in the used machine coolant answer by providing the MSDS sheets from what went into the machine coolant.  

In a tool and saw shop these would be:

  • machine coolant
  • Tungsten carbide
  • Stellite
  • Tool steel
  • Diamond, Borazon or cubic boron nitride wheel.
  • Any additives to the machine coolant    See Note #1
  • Any lubricating oils and greases
  • Any cleaning compound used to clean the machine or the tools   See Note #2
  • These and water should cover it. 

If you add a little bit of the wrong chemical to a sump you can turn thirty gallons of ordinary waste (disposal cost $49 to $90 per barrel) into thirty gallons of hazardous waste (disposal cost $164 to $300 per barrel)  

Note #1  Be very careful about additives.  Chemicals sold to control fungus and bacteria can be very dangerous.  These algaecides and fungicides are often based on nerve agent compounds.  

Note #2  Some of these compounds can be solvent based.  

The trick is to get into the cheapest category where you can prove that you legally belong. 

Used machine coolant is typically sludge or particles, used machine coolant and tramp oils.   Filtering will remove most of the sludge.  The oil can be skimmed off the top and separated that way.    The remaining liquid is probably 90 – 98% water.  This water can be evaporated off.  

You can pay to have the mixture hauled away.  You can separate it yourself and maybe sell the sludge.  You can possible save some money by separating the oil. 

The Laws

The environmental laws would fill several semi-trailers if you took them all together.   Environmental laws are the same as the tax laws or the driving laws in that it is clearly and completely your obligation to know and comply with the law. 

1.  Used grinding machine coolant is regulated under federal law.   It is your obligation to identify the used grinding machine coolant and to dispose of it properly.

40 CFR  Ch. 1 (7-1-96 edition)  Section 261.1  (c)

A “spent material” is any material that has been used and as a result of contamination can no longer serve the purpose for which it was produced without processing;

 “Sludge” has the same meaning used in section 260.10 of this chapter; 

2.  Under 40 CFR and it is the obligation of the producer of the machine coolant to be in compliance with any and all federal, state and local regulations.  The following is a direct quote from federal law.  The law is:

40 CFR Ch. 1 (7-1-96) Edition Subpart A – General 262.10  Purpose, scope, and application (h)

Note: 2 A generator who treats, stores, or disposes of hazardous waste on-site must comply with the applicable standards and permit requirements set forth in 40CFR parts 264, 265, 266, 268, and 270. 

3.  According to 40 CFR Ch. 1 (7-1-96 edition)  Section 261.1  (b) (2) (i)

A material which is not identified as a solid waste in this part, or is not a hazardous waste identified or listed in this part, is still a solid waste and a hazardous waste for purposes of these sections if: 

4.  40 CFR Ch. 1 (7-1-96 edition)  Section 261.1 (b) (2) (ii)

In the case of section 7003, the statutory elements are established. 

5.  40 CFR Ch. 1 (7-1-96 edition)  Section 261.1  (b) (2) (ii) (c)

For the purposes of sections 261.2 and 261.6:

(1) A “spent material” is any material that has been used and as a result of contamination can no longer serve the purpose for which it was produced without processing; 

Sample Test Results


Your Results

Legal Limits

Fats, Oil and Grease,  mg/L



Total Petroleum Hydrocarbons,  mg/L



Hexavalent Chromium,  mg/L



TCLP Metals,  mg/L



Arsenic  (As)



Barium  (Ba)



Cadmium  (Cd)



Chromium  (Cr)



Lead  (Pb)



Mercury  (Hg)**



Selenium  (Se)



Silver  (Ag)



Oil and Grease testing performed by EPA Method 413.2 (Partition Infrared)
Total Petroleum Hydrocarbon testing performed by EPA Method 418.1
Hexavalent Chromium testing performed by Standard Method  307-B
TCLP by EPA Method 1311
Metals performed by EPA Method 6010
* Cadmium detection limit raised due to matrix effects
** Mercury analysis by EPA Method 7470 

There may be some surprises here.  The water in machine coolant evaporates.  Make up water is added and that evaporates.  This can leave you with high levels in your tank of whatever was a low level in the water you added. 

There can also be things show up that were in the chemicals you added but whose concentrations were too low to be put on an MSDS sheet.  

Typical Batch

40 CFR Ch. 1 Section 261.3  p. 36

There is a reference to “An analysis of a typical batch” in this section.  This section does not apply to grinding or machining wastes, but the concept can apply to other systems. 

In effect the principle here is that a process that is done the same way each time and uses the same chemicals each time will produce the same waste each time.  Therefore it should be necessary to do a full set of tests only once to establish the process.  It shouldn’t be necessary to do a full retesting unless the process changes.  This seems to be a generally accepted practice among waste management companies.   They will typically require a one-time testing fee when signing on a new customer.  There is definite requirement to do retesting when the process changes. 

Chrome Classification

A determination of the classification of the chrome component of your waste as required by law.

There are several kinds of chrome or chromium.  Some are considerably more reactive than others and thus they are a much bigger problem environmentally.  Chrome from tool and machining operations is almost certainly trivalent or the safer chrome.  Chrome from electro-plating operations is more likely to be hexavalent chrome. 

This test was run to establish that you have the safer chrome as per federal law. 

40 CFR Ch. 1 section 261.4 (b)

Solid wastes which are not hazardous wastes 

40 CFR Ch. 1 section 261.4 (b) (6) (I)

(A) The chromium in the waste is exclusively (or nearly exclusively) trivalent chromium; and

(B) The waste is generated from an industrial process which uses trivalent chromium exclusively (or nearly exclusively) and the process does not generate hexavalent chromium; and

(C) The waste is typically and frequently managed in non-oxidizing environments.   

Classification Options For Your Waste

Because of the constituents of your waste, especially TCLP, You have four options: 3 options as a hazardous waste generator and one option as a recycler. 

Option 1:  Large Quantity Generator  (LGQ)

Generates more than 1,000 kg. (2,200 #) of hazardous waste per calendar month

Generates more than 1 kg. (2.2 #) of acute hazardous waste per calendar month

Must obtain an EPA ID #

Properly identify, package and label waste

Properly manifest, transport and dispose of waste

May store waste up to 90 days without a storage permit 

Option 2:  Small Quantity Generator (SQG)

Generates more than 100 kg. but less than 1,000 (220 - 2,200 #) of hazardous waste per calendar month

Generates more than 1 kg. (2.2 #) of acute hazardous waste per calendar month

Must obtain an EPA ID #

Properly identify, package and label waste

Properly manifest, transport and dispose of waste

May store waste up to 180 days without a storage permit

Never accumulate more than 6,000 kg. of hazardous waste on property 

Option 3:  Conditionally Exempt Small Quantity Generators  (CESQG)

If you meet essentially three requirements:

Must generate less than 100 kg. (220#) of hazardous waste per calendar month

Must generate less than 1 kg. (1.1 #) acute hazardous waste per calendar month

Never accumulate more than 100 kg. of hazardous waste on property 

Then you have the following advantages

-  Not required to obtain an EPA ID#

However you must:

-  Properly identify, package and label waste

-  Properly manifest transport and dispose of waste 

Option 4:  Recycler

Amount of material generated is not a factor

Do not need an EPA ID #

Properly identify, package and label waste

Properly manifest, transport and dispose of waste

May store waste up to one calendar year

Cannot accumulate more than 1 calendar year’s worth of waste.  

Advantages of  recycling

1.  You do not have the cost of compliance with the hazardous waste licensing and inspections if you do not generate hazardous waste. 

2.  Your disposal costs are considerably lower with recyclable material than they are with hazardous waste.  Proper classification of your waste can be critical.  We had a client who was having his used grinding machine coolant hauled away as a hazardous waste at about $275 to $300 a barrel.  When he legally relabeled it as “grinding machine coolant for recycling” his costs dropped to $90 a barrel. 

Avoid being a hazardous waste generator 

40 CFR Ch. 1 Section 261.1 (c) (4) 

A material is “reclaimed” if it is processed to recover a usable product or if it is regenerated.  

40 CFR Ch. 1 Section 261.1 (c) (8)

A material is “accumulated speculatively” if it is accumulated before being recycled.  A material is not accumulated speculatively, however, if the person accumulating it can show that the material is potentially recyclable and has a feasible means of being recycled: and that – during the calendar year (commencing on January 1) – the amount of material that is recycled, or transferred to a different site for recycling, equals at least 75 percent by weight or volume of the amount of that material accumulated at the beginning of the period.  In calculating the percentage of turnover, the 75 percent requirement is to be applied to each material of the same type (e.g. slags from a single smelting process) that is recycled in the same way.   

The very best thing to do is to have your waste classified as something besides hazardous waste.  If you have hazards waste then you are required to follow expensive testing and reporting procedures.  If you meet the requirements for reclamation then you do not have hazardous waste.  The requirements are generally pretty simple. 

Used grinding machine coolant is probably suitable for reclamation.   The metals in the machine coolant and the sludge are probably also suitable for reclamation. 

Requirements for classifying your used machine coolant and sludge as materials for reclamation are pretty simple.  

40 CFR section 261.2 (7) 

A material is “recycled” if it is used, reused or reclaimed.  

40 CFR Section 261.2 (e) (1)

Materials are not solid wastes when they can be shown to be recycled  

1.  You have to prove there is a market for the material. 

You have to prove that someone is interested in using your used machine coolant and / or sludge for reclamation. 

40CFR section 261.3  (f)

Documentation of claims that materials are not solid wastes or are conditionally exempt from regulation.  Respondents in actions to enforce regulations implementing subtitle C or RCRA who raise a claim that a certain material is not a solid waste, or is conditionally exempt from regulation, must demonstrate that there is a known market or disposition for the material, and that they meet the terms of the exclusion or exemption.  In doing so, they must provide appropriate documentation (such as contracts showing that a second person uses the material and an ingredient in a production process) to demonstrate that the material is not a waste, or is exempt for regulation.  In addition, owners or operators of facilities claiming that they actually are recycling materials must show that they have the necessary equipment to do so.  

[50 FR 664, Jan. 4, 1985, as amended at 50 FR 33542, Aug. 20, 1985; 56 FR 7206, Feb. 21, 1991; 56 FR 32688, July 17, 1991; 56 FR 42512, Aug. 27, 1991; 57 FR 38564, Aug. 25, 1992; 59 FR 48042, Sept. 19, 1994] 

Establishing a market  

Find someone who will buy it.  If you can't do that it may be cheaper to find someone who will haul it away for reuse.   We separate cardboard from other trash because it is cheaper to have carbaord hauled away than regular trash.       

Sludge and swarf

If you have sludge from grinding tungsten carbide then it is worth reclamation for the cobalt or nickel. If you are grinding knives or some of the high chrome saw tips then the sludge has reclamation value for the steel and the chrome.  

Machine Coolant

Safety-Kleen has a used machine coolant and industrial oil reclamation program.   You can contact Safety-Kleen at 800 323-5040   They have 175 collection facilities and 18 processing facilities nationwide. 

Once again you do not have to use Safety-Kleen.  The fact that they are in the reclamation business proves the economic part of the reclamation requirement. 

We mention Safety-Kleen by name for several reasons.  They are national, they are good to work with and they are absolutely reputable.   There are other companies in the area that are also good and reputable.  There have also been histories of companies that were neither good nor reputable.  

Note:  You are responsible for your wastes.   If the waste hauler or waste treater you select does something illegal it can, and almost certainly will, come back on you.  

2.  You have to get rid of most of the material once a year.

40 CFR Ch. 1 Section 261.1 (c) (8)

: and that – during the calendar year (commencing on January 1) – the amount of material that is recycled, or transferred to a different site for recycling, equals at least 75 percent by weight or volume of the amount of that material accumulated at the beginning of the period.  In calculating the percentage of turnover, the 75 percent requirement is to be applied to each material of the same type (e.g. slags from a single smelting process) that is recycled in the same way.  

Essentially you have to have at least 75% of the waste hauled away each year.  

If you do not want to recycle you need to be licensed as a hazardous waste generator.