Auto Body Shops Pollution Prevention Guide
#8 - Automotive Fluids
Automotive fluids, such as antifreeze and cleaning solvents, can be one of the largest waste streams generated in an auto body shop. This section will discuss pollution prevention options for cleaning solvents, antifreeze, and aerosol sprays.
Cleaning solvents are often the largest automotive fluid waste generated in an auto body shop. Automotive cleaning solvents typically contain chemicals such as methylene chloride, toluene, and xylene. Over-exposure to such solvents and their vapors can lead to cancer, nervous system damage, or skin disorders. Waste solvents are most often regulated as hazardous wastes because they may be listed specifically in the regulations, ignitable, or corrosive. The main methods of preventing pollution in parts washing include:
- Selecting less hazardous cleaning methods
- Substituting less hazardous solvents
- Extending the life of the solvent used
Less Hazardous Cleaning Methods
There are a number of cleaning methods that can be selected to help reduce your exposure to chemicals, maximize solvent life, and reduce the amount of solvents used. Three such alternatives are discussed below.
Mechanical Cleaning - Mechanically cleaning parts can be as simple as cleaning dirt and grit off parts with a wire brush before placing them in the solvent sink or parts washer. More elaborate approaches include abrasive material, such as sand or plastic pellets, to "blast" away dirt and grime.
Advantages: Very effective way to remove heavy scale, paint, and grime; can reduce the amount of solvent used to clean parts; abrasive materials may be reused.
Disadvantages: Not suited for the removal of fluid residues; particulates in air may pose a hazard to unprotected operators; waste generated -- a mixture of abrasive media and the material removed (paint, soil, etc.) -- may be considered hazardous.
Modifying Existing Solvent Sinks - Significantly reduced air emissions, worker exposure to hazardous chemicals, and solvent loss due to evaporation can be accomplished through modifying existing solvent sink equipment. Modifications include:
- Adding easy-to-open lids and covers
- Increasing freeboard height (height of tank above the surface of solvent)
- Installing baskets over sink to allow parts to drip-dry
- Reducing room drafts
Advantages: Modifications can be retrofitted onto existing sinks; simple add-ons such as a cover can reduce air emissions significantly; reduced air emissions mean reduced solvent consumption and hence reduced operating costs; add-on controls are relatively inexpensive; they are easy to install and operate; using add-on controls requires no additional labor or skills.
Disadvantages: Performance of modifications is dependent on the design features on the solvent sink; air emissions can be reduced but not eliminated; product loss can be reduced but not eliminated because some residual solvent will escape from the parts to the ambient air.
Enclosed Parts Washers - Enclosed parts washers usually combine washing, rinsing, and drying cycles within one cabinet. Ultrasonic, high- and/or low-pressure sprays, and immersion cleaning parts washers are available.
Advantages: Effective way to clean parts; less-hazardous cleaning solvents, such as water and aqueous-based solutions, can be used; reduces employee exposure to hazardous solvents; less employee time spent washing parts; potentially cheaper cleaning materials; potentially less waste (hazardous and non-hazardous) to dispose of.
Disadvantages: There is a risk of parts rusting, and the resultant wastewater and sludge may be hazardous.
Most parts cleaners use petroleum-based, low flash point solvents (less than 140°F), such as mineral spirits. When used, these solvents may have to be managed as hazardous waste. Fortunately, solvents with higher flash points (greater than 140°F) and aqueous cleaning solutions (detergents) have become available for small parts washers. As long as these alternative solvents don't become contaminated to the extent they meet the definition of a hazardous waste, they can be managed as a non-hazardous waste. Switching to alternative solvents could lower your hazardous waste disposal costs.
If possible, avoid solvents:
- Containing chlorinated and halogenated compounds, such as methylene chloride or perchloroethylene
- Containing xylene or toluene
- Having a flash point under 140°F (flammable)
There are a number of alternative cleaning solvents on the market today; two alternatives are discussed below.
Aqueous Cleaners - Aqueous cleaners are water-based parts cleaning agents composed of detergents, chemical additives, and/or microbes.
Uses: Acidic cleaners work well for removing scale, rust, and oxides. Alkaline cleaners work well for removing cutting oils and coolants, grease, and shop dirt. Neutral solutions are excellent for removing salts, soil, and particulates.
Cost: A typical batch of solution for a 30-gallon unit requires approximately 4 pounds of powdered cleaner and can cost between $25 and $50. Solution life ranges from three weeks (heavy use) to 4 months (light use).
Advantages: Most are non-hazardous; can reduce the risk of fires; waste can be considered non-hazardous as long as it has not been contaminated (and thus becomes hazardous).
Disadvantages: Inadequate cleaning power for some uses; there is a risk of pitting or corrosion; rinsing with water may be required; "fresh" solvent can more expensive than petroleum-based solvents; contaminated waste solvent and sludges may have to be managed as hazardous waste.
Terpenes - Terpene solvents are derived from natural sources such as pine or citrus oils. A common terpene is d-limonene, which is derived from the oils of orange or lemon peels.
Uses: Terpenes work well in removing heavy petroleum greases and residues.
Costs: Costs are closely tied to bath concentrations and recyclability.
Advantages: They are non-corrosive, non-toxic, biodegradable, and not considered an ozone depleter.
Disadvantages: Can have a very strong odor; may be toxic to aquatic life; are highly flammable when sprayed; resultant wastewater and sludge may be hazardous.
Extending Solvent Life
Antifreeze or engine coolant is typically comprised of ethylene glycol and corrosion inhibitors. It is found in liquid-cooled engines and is designed to transfer heat from a vehicle's engine to its radiator. Over time, antifreeze can become contaminated with traces of fuel, metals, and grit, and can break down to form acids that corrode the cooling system.
Because used antifreeze can be toxic to animals, birds, fish, and humans, it should never be:
- Poured down a sanitary sewer unless it is non-hazardous and the local wastewater treatment plant authority has approved such action.
- Poured down a septic system. The used antifreeze could contaminate or destroy the system, endangering human health and the environment.
- Poured down a storm sewer opening or on the ground. Storm drains may drain directly into local streams or lakes.
The main pollution prevention options for antifreeze include:
- Purchase recycled antifreeze
- Selecting less hazardous coolants
- Practicing safe handling procedures
- Extending the life of the coolant
Recycled antifreeze is an option as long as it meets ASTM Standards and will not invalidate a vehicle manufacturer's warranty. You can purchase equipment to recycle your used antifreeze on-site, or you can purchase recycled antifreeze from a supplier (costs about $1.50 per gallon).
Less Hazardous Coolants
Propylene glycol is another alternative to ethylene glycol antifreeze. Propylene glycol is reported to be less toxic than ethylene glycol; however, spent propylene glycol can become just as contaminated by the engine's cooling system as ethylene glycol.
Safe Handling Procedures
The most effective ways to prevent used antifreeze from creating health and environmental hazards are to:
- Stop leaks or spills from occurring.
- Fix leaky radiators immediately.
- Do not accumulate more antifreeze than you need (this prevents it from becoming out-dated before you can use it).
- Store leftover antifreeze in its original labeled container and make sure the lid is secure.
- Clean up spills or leaks immediately.
- Do not mix used antifreeze with other wastes. Mixing wastes may limit your options for reusing, recycling, or disposing of the mixture.
Extending Coolant Life
Replace antifreeze only when needed. Visually check antifreeze for particulates and test for freeze point and pH. Fresh antifreeze or corrosion inhibitors could be added to adjust these parameters for reuse.
When usable antifreeze must be removed for repairs only, save it in a clean, labeled container. Refill the system with this antifreeze when repairs are done.
Recycle used antifreeze on-site or off-site (refer to the Appendix section for lists of antifreeze recyclers and recycling equipment suppliers).
Aerosol containers are common in most auto body shops. Unfortunately, they are not very economical when you have to pay for the potentially hazardous propellant, the packaging the product comes in (aerosol can), and disposing of the paint left in the can.
Pollution prevention options for aerosol containers include:
- Manage waste aerosol containers properly
- Eliminate the use of aerosol containers
Managing Waste Aerosol Containers
- Try to use all the material in the can before considering it a waste.
- Recycle empty cans if possible.
- If recycling is not an option, empty cans should be disposed of in a licensed solid waste management facility.
- Defective cans should be returned to the supplier or manufacturer.
|Pollution Prevention In Action|
|Helena Chrysler-Nissan in Montana phased out the use of chlorinated solvents and aerosol sprays, and has set up a program to recycle their used antifreeze, oil, aluminum cans, and cardboard. Last year they saved over $10,000 by purchasing solvents in bulk form and avoided disposing of 5,000 aerosol cans. Their recycling efforts have also enabled them to switch to a smaller sized dumpster and reduce their monthly waste disposal costs.|
The following series of questions can help you develop ways of preventing pollution in automotive fluid management.
|1) Have you identified all sources of automotive fluid wastes produced in your shop? Before you start minimizing waste in your shop, you have to first identify your fluid waste sources. Then you can determine which ones can be reused, recycled, or eliminated.|
|2) Do you use less hazardous products? Practice the Laws of Substitution in your shop: substitute water-based or less hazardous solvents for hazardous solvents and substitute refillable, rechargeable dispensers for commercial aerosol spray cans. Keep in mind that not all substitutes are less hazardous, generate less waste, or are easier to dispose of.|
|3) Do you buy fluids in bulk? Buying fluids in bulk can be cost effective and produce less packaging waste. Please note that if you buy in bulk, keep track of the shelf-life of the product and any storage requirements and safety issues that might be pertinent.|
|4) Do you use chlorinated solvents in your shop? Some commonly used solvents and cleaners contain chlorinated or halogenated compounds. Check a product's Material Safety Data Sheet for the words "chlor" or "chloro" in them, like trichloroethane and methylene chloride. These materials have been shown to be hazardous to humans and small amounts of these materials can contaminate large quantities of groundwater.|
|5) Do you use halogenated solvents in your business? Halogenated Solvents can be heavily regulated. Please research your local rules and options for proper disposal. Consider alternative solvents and aqueous parts washers.|
|6) Do you have lids on all tanks & parts washers? Easy-to-open lids and covers help prevent the loss of product due to evaporation and improves indoor air quality.|
|7) Do you use a solvent sink or enclosed parts washer? Solvent sinks, and especially enclosed parts washers, can significantly reduce air emissions and clean more effectively than buckets or tanks.|
|8) Do you use parts cleaning solvent for uses other than cleaning parts? Solvents are expensive -- treat it like gold! Use them only for their intended purposes. Do not waste parts cleaning solvent on floors or use them to clean your hands.|
|9) Do you recycle your used solvents and antifreeze? By recycling used antifreeze and solvents you can conserve resources, decrease the amount of fresh product that must be purchased, and reduce the amount of waste you have to dispose of.|
|10) Do you use any aerosol cans in your shop? Avoid purchasing any material sold in aerosol spray cans. Empty aerosol canisters can be difficult and expensive to dispose of due to the sheer volume and the danger they may pose to the hauler and the environment. Check with your distributor for reusable self-pump dispensers and compressed air rechargeable aerosol dispensers. They may be more expensive up front but they last longer and save money on disposal costs.|