ECAR Fact Sheet for Wisconsin
Aqueous Cleaning

Regulations
Self-Audit Checklist
Best Management Practices
Contacts
Related ECAR Fact Sheets
Other Relevant Resources

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What You Need to Know

Various methods are used to clean oil and grease from auto parts before sale. This fact sheet covers the environmental issues associated with aqueous cleaning methods such as enclosed spray washers, hot dip tanks, pressure washers, and steam cleaning. Solvent Cleaning (e.g., Stoddard solution, mineral spirits) is covered under a separate fact sheet.

Aqueous cleaners are one of the most popular choices for degreasing parts at automotive recyclers and are a good alternative to petroleum-based and halogenated solvents. Some of the benefits of aqueous cleaners are that:

• There is less risk of hazardous exposure for workers;
• They are not flammable or explosive;
• The oils and greases can be removed more effectively; and
• They can provide potential savings in disposal costs, since used aqueous cleaning water may be eligible for discharge into public sewer systems.

Regulations

Depending upon the type and level of contamination, a facility’s used aqueous cleaning solution may be unacceptable for discharge to the local Publicly Owned Treatment Works (POTW) or it may be a hazardous waste. Note that if a facility wishes to discharge its aqueous cleaning solution, the facility’s drain should be connected to a POTW. For information on discharging used solvent to a POTW, see the ECAR Wastewater Fact Sheet. For information on making a hazardous waste determination and managing hazardous waste, see the ECAR Hazardous Waste Fact Sheet.

Listed below are the requirements that a facility must follow when managing and disposing of aqueous-based solvents:

• Make a hazardous waste determination and manage used aqueous solutions accordingly.
• Not discharge used aqueous solution unless it is connected to a POTW or a holding tank or unless the facility has a Wisconsin Pollutant Discharge Elimination System (WPDES) permit. If a facility is discharging to a POTW, the facility must ensure that the discharge meets the effluent limits set by the POTW.

Management and disposal options for these two wastes are discussed below, as well as used filters.

Oil, Sludge, Sediment. Oil skimmed from an aqueous cleaning solution can be managed as used oil and recycled. Most recyclers will accept skimmed oil with used motor oil as long as it is not contaminated with solvent. Contaminated oil and other solids that are removed from aqueous cleaning operations should be managed as hazardous waste unless you have performed tests that indicate they are non-hazardous. For more information, see the ECAR Hazardous Waste fact sheet. If the wastes are non-hazardous, then you should maintain test records that support your determination.

Links to the Regulations and Forms. Use the following links to view the regulations and permit forms pertaining to wastewater.

WPDES General Permit Notice of Intent Form

WPDES General Permit Information

Federal Safe Drinking Water Act Requirements

Self-Audit Checklist

When an inspector comes to your facility, there are certain things he or she checks to see if you are in compliance with environmental regulations. It makes good sense for you to perform a "self-audit" and catch and correct problems before they result in penalties. Also, there are some compliance incentives associated with self-audits (see Audit Policy Page).

Use the following list to audit your aqueous cleaning operation.

1. Are the sludges generated by cleanout of sumps and similar devices associated with aqueous cleaning properly managed and disposed of? Perform a hazardous waste determination for these wastes. If they are found to be hazardous, you must manage them on-site according to hazardous waste rules and dispose of them at an approved facility.
2. Does your facility discharge wastewater from aqueous cleaning? Are the discharges authorized by a permit? Check all uses of water and steam. Determine where wastewater is generated and discharged. You must have a permit or written authorization for all industrial wastewater discharges. Be certain that floor drains and sinks do not discharge to the ground, a septic tank, a storm sewer or a waterway.
3. Determine whether the aqueous cleaning solution discharge will be accepted by the local sewage treatment plant. Obtain all required permits or approvals prior to discharge.
4. If discharge to a sewage plant is not allowed, arrange to recycle and reuse the solution, or properly dispose of the solution. You may need to test the solution to determine whether it is a hazardous waste.

Best Management Practices (BMPs)

Most regulations tell you what you have to do to be in compliance, but they don’t explain how to do it. That’s where "best management practices" come into play. BMPs are proven methods that help you to get into compliance and stay there. The following BMPs are recommended for aqueous cleaning.

• Install cleaning equipment that efficiently uses water or is capable of recycling water.
• Install an on-site capture and reuse system for wastewater. These are commonly used by auto recycling facilities in association with pressure washers and enclosed spray washers.
• Remove caked-on grease and oil from parts with a scraper or knife before aqueous cleaning to reduce cleaning time and water usage.
• Conduct cleaning operations on a contained or indoor impervious surface.
• Do not dispose of used cleaning solution on the ground or into a storm drain.

Contacts

1. For more information, contact Wisconsin’s DNR Auto Salvage Sector Resource Specialist at 715-831-3263, or contact the WDNR Regional Office in your area. For northern Wisconsin, call 715-635-2101 or 715-365-8900; West Central Wisconsin, call 715-839-3700; Northeast Wisconsin, call 920-492-5800; Southeast Wisconsin, call 414-263-8500; and, for South Central Wisconsin, call 608-275-3266.
2. All spills should be immediately reported using Wisconsin’s 24-hour toll free hotline at 800-943-0003. If you discover a discharge through analysis of soil or water, use the Hazardous Substance Release Fax Notification Form.

Related ECAR Fact Sheets

1. Solvent Cleaning
2. Wastewater
3. Hazardous Waste

Other Relevant Resources

1. DNR Fact Sheets on Stormwater Management
2. Best Management Practices for Auto Recyclers

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