Aqueous Industrial Cleaning Chemicals

Due to increasingly stringent federal and state regulations involving solvents, a number of industries are making the transition from solvent "cold cleaning" and vapor degreasing to aqueous chemical cleaning systems. Aqueous industrial cleaning chemicals are cleaners that are based on water as opposed to an organic solvent. Included in this definition of aqueous cleaners are the following:

• Water/Alcohol Cleaners
• Acidic Cleaners
• Alkaline Cleaners
• Emulsions
• Saponifiers

General Description of the Various Aqueous Cleaners Available

Water/Alcohol Cleaners A mixture of water and various forms of alcohol; They are used to remove inorganic contaminants.

Acidic Cleaners Used to remove rust and scale from metal surfaces; Cleans metal without etching; They have a pH < 7; Acidic cleaners may be composed of mineral acids (e.g. nitric, phosphoric, or sulfuric) or organic acids (acetic and oxalic).

Alkaline Cleaners Commonly substituted for halogenated organic solvents in metal degreasing applications; They need inhibitors to prevent etching when used on metal surfaces.

Emulsions Are composed of water soluble solvents that are dispersed in water by surfactants (wetting agents) and emulsifiers; Emulsions are frequently used in ultrasonic cleaning.

Saponifiers Similar to soap in chemistry and cleaning action; They are effective in removing oils, greases, and rosin.

The manufacturer and supplier list and the purchasing guidelines below should help your company choose the aqueous cleaning chemistry that will work best for you.

¹"CFC Alternatives" Environment Program Office, Irvine, CA February 1991

Purchasing Guidelines for Aqueous Industrial Cleaning Chemicals

The following list of cleaning chemical purchasing guidelines was prepared by the Wisconsin Department of Natural Resources to help Wisconsin businesses identify and evaluate pollution prevention opportunities. Although it is not possible to cover every aspect of cleaning chemical selection, the list covers some of the more important points and provides considerations for evaluating industrial chemicals.

What type of aqueous industrial cleaner is best for your company?

1. Choose the appropriate chemistry for the contaminant that needs to be removed. (See Table 1 and consult with the chemical company's staff.)

TABLE 1 Cleaning Effectiveness*

Cleaning Chem.	Organics	Inorganics	Contaminants Polar	Non-polar	Ionics
Water Only	Poor	Great	Great	Poor	Great
Water/Alcohol	Fair	Great	Fair	Fair	Great
Acid	Poor	Great	Fair	Poor	Great
Alkaline	Poor	Great	Fair	Poor	Great
Emulsion	Great	Good	Good	Great	Good
Saponifier	Great	Good	Good	Great	Good

* Source: "CFC Alternatives" Environmental Program Office, City of Irvine, CA February 1991

2. Assess the compatibility of the chemical cleaner with the object to be cleaned.
3. If the object to be cleaned is made of metal that is susceptible to oxidation, you should consider using a cleaning chemical or rinse solution that contains a rust inhibitor.
4. Choose the chemical that will produce the highest level of cleanliness for the part.
5. Determine the type of rinse system (e.g., spray; immersion) that will be necessary to remove the chemical residue from the object being cleaned. Chelating agents, such as EDTA and ammonia salts, are used to dissolve the residue and to reduce the acidity of the rinse solution.
6. Note whether or not the cleaning solution needs to be heated to increase its effectiveness. How much would the heating costs be expected to influence the overall operating costs of the system?
7. Be sure that the aqueous chemical cleaner is compatible with the equipment or cleaning method (e.g., spray; immersion) that you intend to use.
8. Rate the various chemicals on the basis of toxicity, hazards of handling, and ease of adequate treatment and disposal. Try to determine which chemical is the most effective cleaner while still rating high in the three categories mentioned above.
9. Evaluate the expected service life of the chemical cleaner. Can the cleaning solution be filtered and recycled?
10. Evaluate the costs of the cleaning chemical throughout its cycle of use.
    • Purchase Cost
    • Operating Costs
    • Recycling/Disposal Costs

11. If you own or have access to aqueous cleaning equipment, ask the chemical salesperson if you may run a test cleaning of your product with the proposed cleaning chemical. If you don't currently own aqueous cleaning equipment, you should run the test, if at all possible, on the type of equipment (spray, immersion, ultrasonic, etc.) that you expect to purchase.
12. Ideally, the manufacturer or supplier of the chemical you are interested in should have a flexible delivery system that will conform to your chemical usage patterns.
13. Evaluate the quality of the technical support staff of the manufacturer or supplier of the chemical. If you need help in fine tuning the use of the chemical, will someone be available to visit your site?
14. Identify the health and safety precautions necessary when using this chemical in the working conditions at your facility. This information is frequently found in the Material Safety Data Sheet (MSDS) that you should request from the chemical manufacturer or salesperson.
15. Assess the wastewater treatment requirements that apply before discharging the spent cleaning solution to a sewerage treatment facility.

• The treatment required may depend as much on the contaminant that is cleaned from the part as it does on the cleaning solution itself.
• Before making a final decision, verify that the proposed treatment meets wastewater treatment requirements by contacting your sewerage district or the DNR for specific information. Be aware that treatment requirements may vary from one sewerage district to another, and what is adequate treatment in the vendor's area, may not be adequate in yours.

16. Determine if there are any other local, state, or federal health and safety or environmental regulations that apply to the use of the cleaning chemicals.

Some of the purchasing guidelines have been adapted from the February 1991 newsletter "CFC Alternatives" provided by the Environmental Program Office of Irvine, CA. The DNR would like to thank them for their contribution.

Aqueous Industrial Cleaning Chemicals
Manufacturer and Supplier List
August 1991

The Wisconsin Department of Natural Resources (DNR), through the Wisconsin Hazardous Waste Minimization Program, developed the following list of manufacturers and suppliers of Aqueous Industrial Cleaning Chemicals. The list should not be considered to be a complete listing of available manufacturers or suppliers of aqueous chemical cleaners, nor is the list an endorsement of any of the specific manufacturers or suppliers. Hazardous waste generators are advised to thoroughly evaluate the services and compliance status of these companies. The list will be periodically updated. If you have any additions or corrections for this list, please contact the Hazardous Waste Minimization Technical Assistance Program at (608) 267-3763.