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Remediation Technologies Screening Matrix, Version 4.0 4.12 Composting
(Ex Situ Soil Remediation Technology)
  Description Synonyms Applicability Limitations Site Information Points of Contact
Data Needs Performance Cost References Vendor Info. Health & Safety
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>>3.4 Ex Situ Biological Treatment (assuming excavation)

      >>4.12 Composting
Introduction>> Contaminated soil is excavated and mixed with bulking agents and organic amendments such as wood chips, hay, manure, and vegetative (e.g., potato) wastes. Proper amendment selection ensure adequate porosity and provides a balance of carbon and nitrogen to promote thermophilic, microbial activity.

Description:

Figure 4-12: Typical Windrow Composting Process Composting is a controlled biological process by which organic contaminants (e.g., PAHs) are converted by microorganisms (under aerobic and anaerobic conditions) to innocuous, stabilized byproducts. Typically, thermophilic conditions (54 to 65 °C) must be maintained to properly compost soil contaminated with hazardous organic contaminants. The increased temperatures result from heat produced by microorganisms during the degradation of the organic material in the waste. In most cases, this is achieved by the use of indigenous microorganisms. Soils are excavated and mixed with bulking agents and organic amendments, such as wood chips, animal, and vegetative wastes, to enhance the porosity of the mixture to be decomposed. Maximum degradation efficiency is achieved through maintaining oxygenation (e.g., daily windrow turning), irrigation as necessary, and closely monitoring moisture content, and temperature.

There are three process designs used in composting: aerated static pile composting (compost is formed into piles and aerated with blowers or vacuum pumps), mechanically agitated in-vessel composting (compost is placed in a reactor vessel where it is mixed and aerated), and windrow composting (compost is placed in long piles known as windrows and periodically mixed with mobile equipment). Windrow composting is usually considered to be the most cost-effective composting alternative. Meanwhile, it may also have the highest fugitive emissions. If VOC or SVOC contaminants are present in soils, off-gas control may be required.

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Synonyms:

Solid-phase soil treatment, Ex situ treatment.
DSERTS Code: H16 (Composting).

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Applicability:

The composting process may be applied to soils and lagoon sediments contaminated with biodegradable organic compounds. Pilot and full-scale projects have demonstrated that aerobic, thermophilic composting is able to reduce the concentration of explosives (TNT, RDX, and HMX), ammonium picrate (or yellow-D), and associated toxicity to acceptable levels. Aerobic, thermophilic composting is also applicable to PAH-contaminated soil. All materials and equipment used for composting are commercially available.

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Limitations:

The following factors may limit the applicability and effectiveness of the process:
  • Substantial space is required for composting.
  • Excavation of contaminated soils is required and may cause the uncontrolled release of VOCs.
  • Composting results in a volumetric increase in material because of the addition of amendment material.
  • Although levels of metals may be reduced via dilution, heavy metals are not treated by this method. Also high levels of heavy metals can be toxic to the microorganisms.

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Data Needs:

A detailed discussion of these data elements is provided in Subsection 2.2.1 (Data Requirements for Soil, Sediment, and Sludge). Specific data required to evaluate the compost process include contaminant concentration, excavation requirements, availability and cost of amendments required for compost mixture, space available for treatment, soil type, and amenability of the contaminants to composting.

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Performance Data:

Windrow composting has been demonstrated as an effective technology for treatment of explosives-contaminated soil. During a field demonstration conducted by USAEC and the Umatilla Depot Activity (UMDA), TNT reductions were as high as 99.7% in 40 days of operation, with the majority of removal occurring in the first 20 days of operation. Maximum removal efficiencies for RDX and HMX were 99.8% and 96.8%, respectively. The relatively simple equipment requirements combined with these performance results make windrow composting economically and technically attractive.

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Cost:

Costs will vary with the amount of soil to be treated, the soil fraction in the compost, availability of amendments, the type of contaminant, and the type of process design employed.  This composting analysis estimates the cost of composting contaminated soils using windrows.  The cost of providing a treatment pad with leachate collection is included.  The key cost driver information and cost analysis was developed using the 2006 version of the Remedial Action Cost Engineering and Requirements (RACER) software. 

Key Cost Drivers 

·        Contaminant

o       Contaminant type is the primary cost driver for composting.

·        Soil type/total organic content (TOC)

o       Soils of higher density (in general, fine-grained sands and gravels) have lower composting costs, while soils of higher TOC have higher composting costs.  The density influences the mass of soil to be treated, while the percent TOC indicates the level of contamination.

Cost Analysis

The following table represents estimated costs (by common unit of measure) to apply composting technology at sites of varying size and complexity.   A more detailed cost estimate table which includes specific site characteristics and significant cost elements that contributed to the final costs can be viewed by clicking on the link below.

SOIL TECHNOLOGY:

Composting

 

RACER PARAMETERS

Scenario A

Scenario B

Scenario C

Scenario D

Small Site

Large Site

Easy

Difficult

Easy

Difficult

 

 

 

 

 

CUBIC YARDS PROCESSED

13,000

13,000

24,000

24,000

COMPOSTING COST PER CUBIC YARD

$259

$345

$249

$321

TOTAL COST PER CUBIC YARD

$489

$578

$481

$555

COST PER 1000 CUBIC YARDS

$488,988

$577,588

$480,682

$554,982

Detailed Cost Estimate

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References:

Treatment Technologies for Site Cleanup: Annual Status Report (ASR), Tenth Edition, EPA 542-R-01-004

Innovative Remediation Technologies:  Field Scale Demonstration Project in North America, 2nd Edition

Remediation Technology Cost Compendium - Year 2000

Treatment Experiences at RCRA Corrective Actions, December 2000, EPA 542-F-00-020

Abstracts of Remediation Case Studies, Volume 4,  June, 2000, EPA 542-R-00-006

Guide to Documenting and Managing Cost and Performance Information for Remediation Projects - Revised Version, October, 1998, EPA 542-B-98-007

The Composting Alternative to Incineration of Explosives Contaminated Soils, Harry Craig, EPA Region 10 and Wayne Sisk, U.S. Army Environmental Center

Cost and Performance Report: Composting Application at the Dubose Oil Products Co. Superfund Site Cantonment, Florida

Ayorinde, O. and M. Reynolds, December 1989. "Low Temperature Effects on Systems for Composting of Explosives-Contaminated Soils," Part I, Literature Reviews, USACRREL.

California Base Closure Environmental Committee (CBCEC), 1994. Treatment Technologies Applications Matrix for Base Closure Activities, Revision 1, Technology Matching Process Action Team, November, 1994.

EPA, 1996. Composting, Engineering Bulletin, EPA/540/5-96/502.

Federal Remediation Technologies Roundtable, 1995. Remediation Case Studies: Bioremediation, EPA/542/R-95/002.

Federal Remediation Technologies Roundtable, 1997. Remediation Case Studies: Bioremediation and Vitrification, EPA/542/R-97/008.

Unkefer, P.J., J.L. Hanners, C.J. Unkefer, and J.F. Kramer, April 1990. "Microbial Culturing of Explosives Degradation," in Proceedings of the 14th Annual Army Environmental Symposium, USATHAMA Report CETHA-TE-TR-90055.

USAEC, 1997. "Composting of Nitrocellulose Fines" in Innovative Technology Demonstration, Evaluation and Transfer Activities, FY 96 Annual Report, Report No. SFIM-AEC-ET-CR-97013, pp. 147-149.

USAEC, 1997. "Cost and Design for Application of Biotreatment Technologies for Explosives-Contaminated Soils" in Innovative Technology Demonstration, Evaluation and Transfer Activities, FY 96 Annual Report, Report No. SFIM-AEC-ET-CR-97013, pp. 79-81.

USACE, 1998. "Bioremediation of Soils Using Windrow Composting", Guide Specifications for Military Construction, CEGS-02191.

WESTON (Roy F. Weston, Inc.), 1993. Windrow Composting Demonstration for Explosives-Contaminated Soils at the Umatilla Depot Activity, Hermiston, Oregon, Final Report, Prepared for USAEC, Contract No. DACA31-91-D-0079, Report No. CETHA-TS-CR-93043.

Williams, R.T., P.S. Ziegenfuss, and P.J. Marks, September 1988. Field Demonstration - Composting of Explosives-Contaminated Sediments at the Louisiana Army Ammunition Plant, USATHAMA Report AMXTH-IR-TE-88242.

Williams, R.T., P.S. Ziegenfuss, and P.J. Marks, March 1989. Field Demonstration - Composting of Propellants-Contaminated Sediments at the Badger Army Ammunition Plant (BAAP), USATHAMA Report CETHA-TE-CR-89061.

Williams, R.T. and P.J. Marks, November 1991. Optimization of Composting for Explosives-Contaminated Soils, USATHAMA Report CETHA-TS-CR-91053.

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Site Information:

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Points of Contact:

General FRTR Agency Contacts

Technology Specific Web Sites:

Government Web Sites

Non Government Web Sites

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Vendor Information:

A list of vendors offering Ex Situ Biological Soil Treatment is available from EPA REACH IT which combines information from three established EPA databases, the Vendor Information System for Innovative Treatment Technologies (VISITT), the Vendor Field Analytical and Characterization Technologies System (Vendor FACTS), and the Innovative Treatment Technologies (ITT), to give users access to comprehensive information about treatment and characterization technologies and their applications.

Government Disclaimer

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Health and Safety:

Hazard Analysis

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