VERMICOMPOSTING

Revision Date: 05/00
Process Code: Navy/Marines: N/A; Air Force: N/A; Army: N/A
Usage: Navy: Medium; Marines: Medium;Army: Low; Air Force: Low
Compliance Impact: Low
Alternative for: Landfilling
Applicable EPCRA Targeted Constituents: N/A
Overview: Vermicomposting is a process that uses red earthworms to consume organic waste, producing castings (an odor-free compost product for use as mulch), soil conditioner, and topsoil additive. Naturally occurring organisms, such as bacteria and millipedes, also assist in the aerobic degradation of the organic material. Vermicomposting is especially useful for processing food waste since the worms consume the material quickly and there are fewer problems with odor. Vermicomposting does not generate temperatures high enough to kill pathogens. For this reason, vermicomposting is more appropriate for food, paper, and yard waste. In some states, vermicomposting is considered as an animal raising, rather than a composting activity, and is exempt from the composting permitting process.

Organic material should be chopped or shredded for faster degradation. Unprocessed materials can be used in vermicomposting, but the time required for complete degradation of the organic waste is generally six months or longer. Vermicomposting does not require a specific carbon-to-nitrogen ratio like traditional aerobic composting methods.

One large-scale vermicomposting operation processes approximately five to six tons of food waste and more than two tons of yard waste per day. This operation uses a raised, 120-foot-long bed or trough that is 2.5 feet deep and eight feet wide, with a mesh floor. The operation is enclosed within a greenhouse-type structure. An adapted manure spreader makes a daily pass over the trough, spreading roughly three inches of prepared organic materials per day. The worms’ castings are mechanically scraped off the bottom of the screen and collected. It takes approximately 21 days to make earthworm castings using this method.

Another large-scale proprietary vermicomposting system called the Vermiconversion System uses thermophilic composting (for pathogen destruction and weed seed neutralization) for three to 15 days, and then places the composting material in vermiprocessing beds or windrows for an additional 30 days. Two to four inches of new material are applied to the rows every other day, not exceeding a total row height of three feet. The beds or windrows can be built on a sloped plastic liner for water reclamation, and can use aeration piping and a sprinkler to maintain proper oxygen and moisture levels.
Compliance Benefit: Vermicomposting will help facilities meet the requirements under Executive Order 13101 requiring executive agencies (e.g. DOD) to incorporate waste prevention and recycling in their daily operations. States and/or localities may have additional regulations on composting which should be followed.

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:
N/A


Safety and Health: If the compost contains food waste and animal products, it should be handled with gloves and care should be taken to wash hands and clothing after processing it. It might be necessary to wear a mask when turning and working with compost to prevent inhaling bacteria or particles.


Benefits:
  • Complete composting of yard waste will reduce the amount of waste generated by an average of 15.9% while the addition of food waste will divert another 6.7% (U.S. EPA, 1994).
  • Vermicomposting produces a more marketable compost, which is nutrient-rich with a smaller particle size, lower odor, and greater nutritional value than other types of compost.
  • Vermicomposting has a less stringent permitting process.
  • Vermicomposting produces compost in about three weeks.


Disadvantages:
  • Vermicomposting requires more management and maintenance than other composting systems to maintain healthy worms.


Economic Analysis: The estimated capital cost for a large-scale facility processing approximately 10 tons/day (2,500 to 3,000 tons/yr) of food and yard waste is approximately $30,000 to $40,000 for a basic reactor system, not including land costs. The cost of materials processing equipment will vary depending on the type of equipment selected. Operating costs may run $40 to $60/ton (including labor, benefits, maintenance, fuel, administration etc.). Alternatively, a 200-ton/day facility using the Vermiconversion System (thermophilic composting followed by vermicomposting) was recently implemented for capital cost of approximately $2,000,000.

Assumptions:

  • Process 2,500 tons/yr of food and yard waste.
  • Produce 2,000 tons/yr of finished compost.
  • Solid waste disposal costs: $13/ton
  • Operating costs (labor & maintenance): $60/ton
  • Avoided topsoil purchases: $50/ton
  • Labor for collection and disposal: 15 hours per week
  • Labor rate: $45/hr

Annual Operating Cost Comparison for Diversion and Disposal Using a Vermicomposting Facility

  Diversion Disposal
Operational Costs:    
Labor & Maintenance: $150,000 $35,100
Landfill Costs: $0 $32,500
Total Operational Costs: $150,000 $67,600
Total Recovered Income: $100,000 $0
Net Annual Cost/Benefit: -$50,000 -$67,600

Economic Analysis Summary

    Annual Savings for Vermicomposting Facility: $17,600
    Capital Cost for Diversion Equipment/Process: $30,000
    Payback Period for Investment in Equipment/Process: < 2 years

Click Here to view an Active Spreadsheet for this Economic Analysis and Enter Your Own Values.
Approving Authority: Approval is controlled locally and should be implemented only after engineering approval has been granted. Major claimant approval is not required.


NSN/MSDS:
Product NSN Unit Size Cost MSDS*
None Identified $  

*There are multiple MSDSs for most NSNs.
The MSDS (if shown above) is only meant to serve as an example.

Points of Contact: Civilian:
Mr. John Longfellow
Klickitat County Solid Waste, ms-ch-27
131 W. Court Street
Goldendale, WA 98620
Phone: (509) 773-4448
FAX: (509) 773-4521
 
Navy:
Mr. Wallace Eakes
Naval Facilities Engineering Service Center
1100 23rd Ave.
ESC 426
Port Hueneme, CA 93043-4370
Phone: (805) 982-4882
DSN: 551-4882
FAX: (805) 982-4832

Vendors: Original Vermitech Systems, Ltd.
2328 Queen Street East
Toronto, Ontario,  M4E 1G9
CA
Phone: (416) 693-1027 

Sources: Mr. John Longfellow, Klickitat County Solid Waste, March 1999.

Biocycle Magazine, October 1994 and February 1995
U.S. EPA, Characterization of Municipal Solid Waste in the United States: 1994 Update.


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