The majority of cars use a liquid cooling system that circulates a liquid around hot engine parts and carries off heat. The liquid is called a coolant. Because the coolant in older automobiles was primarily water, the system used to be referred to as a water-cooled system. Water causes the formation of rust in the water jackets, which acts as a barrier to heat transfer. As a result, all modern cars used a coolant composed of water and additional substances. The most common name for modern coolant is antifreeze. Antifreeze is a substance that is added to a liquid usually water to lower its freezing point. Although various substances have been used in the past, nearly all of the currently produced antifreeze is manufactured with ethylene glycol and methyl alcohol. More than 95% of the antifreeze on the market is "permanent" antifreeze, containing ethylene glycol as the major constituent. The lower boiling methyl alcohol will boil away in a hot radiator and possibly leave the engine unprotected against freezing.
Most commercial antifreeze contains various additives to prevent
corrosion, leaks, and damage to rubber parts and foaming.
Antifreeze is not developed through the petroleum fractionating process.
Although it is an automotive fluid, it will not be included in the
discussion of re-refined automotive petroleum based fluids.
Antifreeze can be included in some recycling programs but should not be
mixed with engine oil as part of an oil recycling or re-refining process.
Most modern automobiles are liquid-cooled and use a mixture of antifreeze
and water as a coolant. Along with additives to inhibit corrosion, antifreeze is
usually based on ethylene glycol, although diethylene glycol, propylene glycol,
and sodium nitrate may also be used. Over time, antifreeze becomes contaminated
with traces of fuel, oil, metals (such as copper, lead, and zinc particles), and
dirt. It also breaks down to form acids that corrode cooling systems. When mixed
with anything other than de-ionized (distilled) water, dissolved minerals in the
antifreeze/water mixture form scale deposits that can block lines.
antifreeze may contain heavy metals such as lead, cadmium, and chromium in high
enough levels to make it a regulated hazardous waste.
A hazardous waste may never be dumped on land or discharged into a
sanitary sewer, storm drain, ditch, dry well or septic system.
It is for these reasons that coolant mixtures are
periodically drained and replaced with fresh, uncontaminated coolant.
Used antifreeze is potentially dangerous in two ways:
Engine coolant is also very hot when checked or removed from an engine. Because of the sticky nature of anti-freeze, burns can be particularly bad. Spill clean up to prevent slipping should be emphasized. As coolant is poisonous, prevention from ingestion is also a concern.
The primary law in the State of California is found in Title 22 CCR,
Chapter 11, Articles 3, 4, 4.5, and 5 as well as Section 66261 and Section 5650
and 12016 of the California Fish and Game Code.
will be regulated as hazardous waste if the results from the Toxic
Characteristics Leaching Procedure (TCLP) indicate metal contents that meet or
exceed the following limits:
Avoid spilling when servicing. Use in-shop reclaiming machines to remove coolant prior to engine work, radiator, heater core, or thermostat remove and replacement. Use dedicated drain pans and mop buckets to segregate coolant drips and spills from other liquids in the shop.
Why recycle antifreeze? It’s Cost-Effective: recycled antifreeze is less expensive than virgin antifreeze. It saves resources. Ethylene glycol is produced from natural gas, a non-renewable resource. Waste antifreeze should be recycled either:
Many sewage treatment agencies responsible for wastewater treatment
discourage or forbid waste antifreeze disposal into sanitary sewers.
Waste antifreeze should never be disposed of down storm drains or into
surface waters because it causes serious water quality problems and may harm
people, pets or wildlife. Doing so
is illegal and punishable by fines of up to $25,000.
Due to the many on-site and off-site recycling options available,
recycling antifreeze is feasible in all parts of the country.
Waste antifreeze can be recycled by three methods:
All waste antifreeze-recycling methods involve two steps:
The type of antifreeze recycling that is best suited to your facility
depends on many factors. The table
in Appendix I summarizes some of these factors for different antifreeze
Can “Organic Acid Technology (OAT) Long-Life Coolants” be
recycled? In 1999, about 30 percent of new passenger
vehicles and 5 percent of heavy-duty equipment was factory filled with OAT
coolants. Many antifreeze-recycling
units can recycle OAT coolants such as DexCool™. The most important factor when recycling OAT coolant is to
use a technology that completely removes the “chemistry” from the waste
coolant. Once the coolant has been
recycled, it may be returned to a conventional or OAT coolant or depending on
the additive package used. Numerous
auto repair and fleet maintenance facilities have used recycled antifreeze
produced from on-site recycling units and mobile and off-site recycling services
for years without experiencing engine damage or other problems as a result.
Are there consumer protection
and manufacturer warranty issues? As
of September 1999, there is no ASTM quality standard for recycled antifreeze.
However, several state agencies, for example California Weights and
Measures, have issued product specifications for recycled antifreeze.
Also, some vehicle manufacturers, (e.g. General Motors, Ford Motor
Company, Detroit Diesel and Cummins) test and certify antifreeze-recycling
equipment or have developed standards for recycled antifreeze.
Because there is currently no single national recycled antifreeze
standard that all recycling methods must achieve, you should select an
antifreeze recycling method after discussing coolant quality specifications and
vehicle warranty concerns directly with your recycling unit or service vendors.
Some vendors can provide certification letters from vehicle manufacturers
or state agencies, or will otherwise guarantee the recycled antifreeze they
The determination of the hazardous characteristic of used radiator
coolant has already been determined by the state of California, it is a
hazardous waste. In addition,
radiator coolant has the potential to become contaminated with chlorinated
solvents and other contaminates if improperly handled or stored. Radiator Coolants are ethylene glycol based and should not be
added to used oil for recycling.
You need to control your waste radiator coolant storage from exposure to
rainwater and the resulting run-off into the storm water drain or sewer system.
Radiator Coolant should not be dumped into septic systems, gutters, and
storm systems or onto the ground. Used
radiator coolant is a hazardous waste and cannot be released into the sanitary
sewer or storm drains! A facility
must determine that its discharges are non-hazardous as described in 40 CFR 403
Call the your local waste treatment facility for answers to your
questions concerning storm water runoff or discharging to the sewer.
Antifreeze recycling wastes may be contaminated with metals such as lead,
chromium, cadmium, copper, or zinc. Depending
on the type of recycling performed; wastes may include filters, sludge or
resins. As with all wastes, you
should obtain data, or test the waste to determine whether it is hazardous and
dispose of it accordingly. Off-site
and some mobile recycling service vendors will dispose of the wastes for you. If
your vendor manages your wastes for you, make sure that proper waste
determination and disposal is performed.