RECYCLING INDUSTRIAL WIPE RAGS USING THE OZONE LAUNDRY SYSTEM

Revision Date: 11/01
Process Code: Navy and Marine Corps: SR-02-99; Air Force: CL05; Army: VHM
Usage: Navy: High; Marine Corps: Medium; Army: Medium; Air Force: Low
Compliance Impact: Low
Alternative for: Hazardous/Solid Waste Disposal
Applicable EPCRA Targeted Constituents:
Numerous, non-specified

Overview: Currently many military activities dispose of large quantities of soiled industrial wipe rags. To address this problem, the Ozone Laundry System has been developed to clean all types of fabric industrial wipe rags contaminated with oil & grease or RCRA hazardous wastes.The system is similar to a conventional hot-water industrial laundry except for the addition of the ozone generating equipment and the fact that it uses cold water.To simplify the installation of the system, it has a modular design.Each module consists of a 135lb. capacity industrial washing machine, a 170 lb. capacity dryer and the associated ozone generation equipment.One module is sized to annually clean approximately 150,000 lbs. of soiled rags.

The difference between a conventional washing machine and an ozone washing machine is the addition of a pump/piping loop. Water from the washer drum is circulated through this loop. A venturi is used to inject the gaseous ozone. The ozone is generated in a three-step process; first air is compressed in an air compressor; next the resulting compressed air is passed through a pressure swing adsorption oxygen generator; and finally the oxygen is fed to corona discharge ozone generators.

The addition of gaseous ozone to the wash and rinse cycle offers several benefits to a laundry facility. Ozone is a strong chemical oxidant that treats the resulting wastewater such that the oil and grease are much less likely to redeposit on the fabrics. This allows for the quantity of rinse water to be significantly reduced. Since the ozone breaks down the organic contaminants, the resulting wastewater is much cleaner than that from a conventional industrial laundry. For most cases, the system wastewater may be directly discharged to a domestic sewer system without pretreatment. The addition of ozone also compliments the cleaning chemicals so that less chemicals are required. This improved cleaning action is accomplished using cold water since the solubility of gaseous ozone in water is reduced as the water temperature increases.

The Ozone Laundry System is designed for simple operation and minimal maintenance. Once the wash program is set, system operation basically involves just turning the machine on to initiate the preset washing program. Cleaning chemicals are automatically injected into the washing machine. Like any industrial laundry, this system requires the handling of significant quantities of fabrics. A full-time dedicated operator is recommended. Operator-performed maintenance basically consists of periodically cleaning the filter baskets. A more extensive preventive maintenance program is also required.


Compliance Benefit: Compared to facilities that are conventionally washing their used wipe rags, the use of the ozone laundry system will decrease the use of water. This helps facilities meet the requirements under Executive Order (EO) 12902 which requires federal facilities to implement water conservation projects. In addition, since the ozone laundry system breaks down the organic contaminants, the resulting wastewater is cleaner and is much more likely to be permitted for direct sewer discharge.

The use of the ozone laundry system in place of rag disposal will decrease the amount of solid or hazardous waste which helps facilities comply with EO 13101 - Federal Acquisition, Recycling and Waste Prevention.

The compliance benefits listed here are only meant to be used as a general guideline and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g. the amount of workload involved.


Materials Compatibility: Ozone is a strong oxidant that can destroy numerous types of materials. Since it rapidly decomposes, it cannot be stored and must be generated on-site during the laundry process. All surfaces of the Ozone Laundry System that come in contact with ozone are chemically resistant. Ozone does not remain in the cleaned fabrics because of its rapid decay. It is therefore, less damaging to fabrics than a chemical bleach, since bleach leaves a chemical residual.


Safety and Health: Exposure to gaseous ozone is harmful, therefore the Ozone Laundry System has been designed to automatically shutdown if an ozone leak develops. Since the cleaning process does not require a pH change similar to a conventional industrial laundry, the only required cleaning chemical is a surfactant. This chemical poses very little risk for the system operator. Depending on the contaminants present on the soiled rags, the operator is required to wear the appropriate personal protection equipment. In most cases this will be rubber gloves.

It is recommended that your local industrial health specialist and your local health and safety personnel be consulted, and the appropriate MSDS be reviewed prior to implementing any wipe rag laundering program.


Benefits: For activities that are not recycling wipe rags:
  • Total costs are reduced by recycling wipe rags.
  • Quantity of rags disposed of is significantly reduced.

For activities that are conventionally washing wipe rags:

  • Total laundering costs are reduced.
  • Water use is reduced.
  • Cleaning chemical use is reduced.
  • Hot-water use is eliminated.
  • The Chemical Oxygen Demand of the resulting wastewater is reduced approximately 71%.
  • Washing cycle time is reduced.
  • Laundered rags are cleaner.


Disadvantages:
  • A significant capital investment is required. A system sized to annually clean 150,000 lbs. of wipe rags will cost approximately $75,000.
  • The system uses patented equipment with only one supplier. In addition, the technology is relatively new and therefore long term performance data is not available.
  • To obtain maximum benefit from the system, a full-time operator is required.


Economic Analysis: A basic economic analysis is provided below. The Ozone Laundry System is a direct substitution for the disposal of soiled industrial wipe rags as either solid or hazardous waste, the cleaning of such rags using a conventional hot-water laundry, or the use of a commercial rag cleaning service. Operating costs for the system are dependent on the local utility and labor costs.

To assess the systems economic advantage or disadvantage relative to the competing options, the attached spreadsheet program is provided. To use the program, enter the requested information on quantity of rags to be laundered, labor and utility costs, commercial rag cleaning service costs and rag disposal costs. The program will calculate the cost per pound of cleaned rags for the three options and the payback period for using the Ozone Laundry System. These results can then be used to justify a more detailed site-specific analysis. In general, the economics of the Ozone Laundry System are very favorable when the activity experiences a high rag loss rate, provides service for naval ships or when the activity disposes of rags at a high disposal cost.


Assumptions
  • The laundry equipment ( i.e. washer, dryer & ozone machine) has a service life of 15 years
  • The interest rate used in the calculations is 8%
  • The costs are calculated for a rag loss rate of 10%
  • The price of baled rags is $0.40/lb. This is the current price under NSN 7920-00-205-1711
  • All of the cost for operating labor is included in the washing costs
  • The initial costs for baled rags is based on obtaining a 3 month supply
  • The dryer cost is based on a 45 minute drying cycle and a 3 minute cooldown cycle
  • The dryer utility costs were calculated based on their rated 370,000 BTU/hr gas supply and their two 1.5 Hp motors
  • The annual maintenance cost is assumed to be 2% of the equipment purchase and installation cost
  • Non-Labor Rag Collection Costs are assumed to be $100 per month
  • The cost per lost rag assumes that charges are only made for losses that exceed 10%


Variabled

O3 Laundry System

Rag Disposal Service

Rag Cleaning Service

Loads of Laundry per Month

105

105

105

Number of Rags per Load

110

110

110

Monthly Amortized Cost of Initial Supply of Rags Laundry Equipment

$ 135.00

-

-

Monthly Amortized Cost of Laundry Equipment

$ 730.00

-

-

Monthly Laundry Operating Costs (excluding labor)

$ 827.00

-

-

Monthly Labor Costs (including OH)

$ 4,167.00

-

-

Monthly Equipment Maintenance Cost

$ 125.00

-

-

Monthly Cost for Rag Collection

$ 100.00

-

-

Monthly Replacement Rag Costs

$ 462.00

$ 4,620.00

-

Total Monthly Cost for Disposal of All Oily Rags

-

$ 11,550.00

-

Weekly Cost per Clean Rag

-

-

$ 0.03496

Weight of Rags

-

-

14/lb.

 

 

 

 

Total Monthly Cost

$ 6,545.00

$ 16,170.00

$ 5,653.00

 

 

 

Total Cost per Pound of Rags

$ 0.57

$ 1.40

$ 0.49

Payback period for Using an Ozone Laundry System

-

8 months

N/A

 
The calculations indicate that the Ozone Laundry System is a worthwhile substitute for the disposal of rags, but it is more expensive than having a contractor pick up and clean the rags. However, there may be instances where a contractor cleaning service may be unavailable or inconvenient, for example:
  • When ships are located out at sea and unable to access contractor rag cleaning services.
  • When there are large discrepancies from one month to the next in the number of rags used/needed to be cleaned.
  • When the facility is located in a remote location and unable to access contractor rag cleaning services.
  • When it is difficult for the end user to keep track of the used rags. Contractors often issue a specific number of rags to a site per month. If rag loss rates are high (>20%), the site may have to determine the administrative costs associated with keeping track of the used rags and compare those costs with the lost rags fees imposed by the contractor.
Approving Authority: Approval is controlled locally and should be implemented only after engineering approval has been granted. Major claimant approval is not required.

 

Points of Contact: Navy:
Mr. Bruce Holden
Naval Facilities Engineering Service Center
421/BH
1100 23rd Avenue
Bldg. 1100
Port Hueneme, CA  93043-4370
Phone: (805) 982-6050 DSN 551-6050
Fax: (805) 982-1409
E-mail: holdenbb@nfesc.navy.mil

The following activity is currently using an Ozone Laundry System:

PWC  San Diego
Navy Public Works Center - Code 930
2730 McKean Street, Suite 1
San Diego, CA  92136-5294
Mr. Paul Wohlgemuth
Phone: (619) 545-6563 DSN 735-6563
Fax: (619) 545-6525

 

Vendors: The Ozone Laundry System is patented equipment that is exclusively provided by Cyclopss Corporation. Their address and point-of-contact are listed below.

Cyclopss, Inc.
3646 West 2100 South
Salt Lake City, UT  84120
Phone: (800) 972-9091
Fax: (801) 972-9092
P.O.C. Dr. Durand Smith
E-mail: Durands@aol.com
Sources: RCRA Hotline, November 1999.
Bruce Holden, Naval Facilities Engineering Service Center, November 1999.

 


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