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Alternative Aqueous Cleaners Demonstration Project

Final Report
City of Los Angeles
Environmental Affairs Department
Hazardous and Toxic Materials Office
August 1999


This publication is intended to assist City of Los Angeles departments that clean parts by providing information on aqueous cleaners and their performance. The units demonstrated for this project are among the many aqueous cleaning units available from a wide variety of manufacturers and vendors. This publication does not endorse, recommend, or approve of any specific trade names, manufacturers, products, vendors, or services.

Executive Summary

The City of Los Angeles (City of LA) is evaluating alternative aqueous cleaners to assist City of LA departments identify cost-effective equipment and water-based solutions that best meet department cleaning needs. The project is being coordinated by the Environmental Affairs Department (EAD) Hazardous and Toxic Materials (HTM) Office with assistance from the General Services Department Purchasing Division and several participating City of LA departments that demonstrated aqueous cleaning units for this project.

The South Coast Air Quality Management District has restricted the use of solvent cleaning in the LA area since January 1, 1999, requiring facilities to implement aqueous cleaning. In order for the City of LA to comply with South Coast Air Quality Management District regulations, the current aqueous cleaning vendor, Safety-Kleen Corporation, converted all department facilities to aqueous cleaners by replacing solvent sink-top and immersion units with aqueous sink-top and immersion units. However, some City of LA departments are having difficulty maintaining cost-effective cleaning efficiency using these aqueous sink-top and immersion units for the following reason:

  1. Aqueous sink-top and immersion units do not provide equivalent cleaning performance to solvent sink-top and immersion units. Aqueous cleaning requires solution heat and mechanical agitation to achieve the same cleaning efficiency as solvent. However, comparable cleaning efficiency often cannot be obtained using sink-top and immersion units because of limitations in the amount of solution heat and mechanical agitation that can be applied in a manual cleaning application.
  2. Aqueous sink-top and immersion units may not be appropriate for some cleaning applications. With aqueous cleaning, the type of unit and solution that is most appropriate depends on specific parts, soils, and cleaning applications. Therefore, different types of aqueous units and solutions may be required at different facility and shop locations.
  3. Some City of LA staff reported skin problems with the strongly alkaline solution provided by the current vendor in some of the existing aqueous cleaning units.

The Alternative Aqueous Cleaners Demonstration Project was implemented to demonstrate and assess the cleaning effectiveness of a variety of aqueous cleaning equipment and solutions. In addition to alternative sink-top and immersion units, automated aqueous cleaning units such as spray cabinets and ultrasonic units were also demonstrated. Between January and May 1999, eight different aqueous cleaning units were demonstrated at five City of LA fleet maintenance and equipment repair facilities: (1) General Services 7th Street Facility, (2) Police Department Piper Tech Facility, (3) World Airports Fleet Maintenance Facility, (4) Police Department Central Facility, and (5) Recreation and Parks Equipment Repair Facility. The demonstration results are being used to provide City of LA departments a wider choice of alternative cleaners and thereby help fulfill their current and future cleaning needs. In addition, the demonstration results can be used as part of a larger LA City Council motion to determine the availability of non-toxic alternatives and the feasibility of eliminating toxic and hazardous materials from purchasing and replacing them with non-toxic alternatives.

The aqueous cleaning units and solutions demonstrated were selected based on the needs of each demonstration facility as well as research and previous testing experience at City of LA departments and other facilities. The demonstration project did not include all potentially effective units or solutions and, therefore, the results should not be interpreted by the reader as all inclusive.

This Executive Summary summarizes overall results of the demonstration project, including: (1) overall conclusions, (2) aqueous cleaning performance and unit design, (3) servicing requirements and waste generation, (4) economics, and (5) vendor leasing, servicing, and waste management service.

OVerall Conclusions

  1. Numerous alternative aqueous cleaning units are available that equal or exceed the cleaning performance of existing aqueous cleaning units used in City of LA facilities.
  2. Spray cabinets and ultrasonic units provide a much higher level of cleaning performance than sink-top and immersion units because of the greater amount of solution heat and mechanical agitation applied during the cleaning process.
  3. Spray cabinets and ultrasonic units require significantly less cleaning labor than sink-top and immersion units.
  4. Noncaustic aqueous cleaning solutions (pH between 7 and 9) are available for sink-top and immersion units that provide equal or better cleaning performance and cause less skin irritation than the alkaline solution (pH 10.8) often used in the existing aqueous units in City of LA facilities.
  5. City of LA facilities can best meet their cleaning needs by using a combination of two or more types of aqueous cleaning units. City of LA facilities can reduce the total number of cleaning units they use by installing spray cabinets and ultrasonic units with large cleaning capacities in place of several smaller units.

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