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Assessment and Remediation of Contaminated Sediments (ARCS) Program

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Prepared by
Michael Giordano and Evelyn Meagher-Hartzell
Science Applications International Corporation
Cincinnati, Ohio

for the
Assessment and Remediation of Contaminated Sediments (ARCS) Program
U.S. Environmental Protection Agency
Great Lakes National Program Office
Chicago, Illinois

 

Bench-Scale Evaluation of ReTeC's Thermal Desorption Technology on Contaminated Sediments from the Ashtabula River

US Environmental Protection Agency. August 1994. Abstract, Introduction and Table of Contents to "Bench-Scale Evaluation of ReTeC's Thermal Desorption Technology on Contaminated Sediments from the Ashtabula River," EPA 905-R94-008. Chicago, Ill.: Great Lakes National Program Office.

ABSTRACT

The Great Lakes National Program Office (GLNPO) leads efforts to carry out the provisions of Section 118 of the Clean Water Act (CWA) and to fulfill U.S. obligations under the Great Lakes Water Quality Agreement (GLWQA) with Canada. Under Section 118(c)(3) of the CWA, GLNPO is responsible for undertaking a 5-year study and demonstration program for the remediation of contaminated sediments. GLNPO has initiated an Assessment and Remediation of Contaminated Sediments (ARCS) Program to carry out this responsibility. In order to develop a knowledge base from which informed decisions may be made, demonstrations of sediment treatment technologies are being conducted as part of the ARCS Program. A bench-scale study using the ReTeC Thermal Desorption 1000 lb/hr technology is the subject of this report. This study took place at Star Refinery in Delaware City, DE on September 25, 1991. The specific objectives for this effort were to determine process extraction efficiencies for polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs); to conduct a mass balance for solids, water, oil, PCBs, and PAHs; and to examine process effects on metals, oil and grease, and several other parameters.

The ReTeC Holo-Flite(TM) Screw Processor was tested using a sediment sample obtained from the Ashtabula River. The concentrations of the contaminants of concern in the sediment were 14.6 mg/kg PCBs and 6.1 mg/kg PAHs. The PCB and PAH concentrations of <0.6 and <2.4 mg/kg, respectively, were found in the treated solids. This corresponds to PCB and PAH removals of >96 and >60 percent, respectively. Since the concentrations of individual PAHs in the feed and treated solids are very close to detection limits, significant error is associated with the calculated PAH removals. The percent removal achieved for PAHs can be attributed to the method used to quantify the individual PAHs, making this result an unreliable reflection of the technology's ability to remove PAHs. Metals analyses were performed on the treated solids and untreated sediments. The data demonstrate that except for mercury, there is no indication that the ReTeC technology effectively removes metals. The feed and treated solids were analyzed for percent moisture, oil and grease, total organic carbon (TOC), volatile solids, and pH. Moderate reductions were experienced for oil and grease and total volatile solids (i.e., 56.6 percent and 44.4 percent, respectively). Because of the relatively small amount of material treated, accurate mass balances were not possible.


Table Of Content 

Acknowledgements
Abstract
List of Figures
List of Tables

1.0 Executive Summary

2.0 Introduction

2.1 Background
2.2 Sediment Descriptions
2.3 Sediment Characterization
2.4 Technology Description

3.0 Treatability Study Approach

3.1 Test Objectives and Rationale
3.2 Experimental Design and Procedures
3.3 Sampling and Analysis

4.0 Results and Discussion

4.1 Summary of Phase I Results
4.2 Phase II Results
4.3 Summary of Vendor Results
4.4 Quality Assurance/Quality Control

Appendix A - Thermal Treatability Testing, Ashtabula River Sediments, Great Lakes Program Office
Appendix B - Quality Assurance/Quality Control
Appendix C - Quality Assurance Project Plan
Appendix D - Battelle Analytical Results


1.0 EXECUTIVE SUMMARY

The ReTeC Holo-Flite(TM) Screw Processor was tested using sediment obtained from the Ashtabula River. The contaminants of concern in the sediment were PCBs and PAHs. Samples of the feed and the treated solids produced using the ReTeC technology were analyzed by Battelle Marine Sciences Laboratory for PCB and PAH contamination. The data from these analyses are presented in Table 1.

The data in Table 1 indicate that PCB and PAH concentrations of <0.6 and <2.4 mg/kg, respectively, were found in the treated solids. This corresponds to PCB and PAH removal of >96 and >60 percent, respectively. Since the concentrations of individual PAHs in the feed and treated solids are very close to detection limits, significant error is associated with the calculated PAH removal. The percent removal achieved for PAHs can be attributed to the method used to quantify the individual PAHs, making this result an unreliable reflection of the technology's ability to remove PAHs.

Metal analyses were performed on the treated solids and untreated sediments. The data demonstrate that except for mercury, there is no indication that the ReTeC technology effectively removes metals. The feed and treated solids were analyzed for percent moisture, oil and grease, TOC, volatile solids, and pH. Moderate reductions were experienced for oil and grease and total volatile solids (i.e., 56.6 percent and 44.4 percent, respectively). The results of these analyses are discussed in more detail in Section 4.2.

Given the size of the unit employed during testing (1000 lb/hr), the relative small amount of material available for treatment (460 lbs), and the relatively large amount of material trapped within the system following treatment (approximately 107 lbs, assuming perfect recovery), accurate mass balances could not be calculated. To address the issue of equipment contamination fully, rough mass balances were performed for solids, water, oils, and PAHs. As shown in Table 2, the excessively high values obtained for oil and PAHs support suspicions of processor contamination.

Small vials of the residuals from the pilot-scale test were retained and given to the EPA Technical Project Manager for the GLNPO for "show" purposes. All quantities of the test products (water, solids, and oil residuals) from the pilot-scale test were sent to the analytical laboratory, Battelle Marine Sciences Laboratory, for analysis. None of the residuals were retained and shipped to EPA for possible further treatability studies.

2.0 INTRODUCTION

The Great Lakes National Program Office (GLNPO) leads efforts to carry out the provisions of Section 118 of the Clean Water Act (CWA) and to fulfill U.S. obligations under the Great Lakes Water Quality Agreement (GLWQA) with Canada. Under Section 118(c)(3) of the CWA, GLNPO was responsible for undertaking a 5-year study and demonstration program for the remediation of contaminated sediments. Five areas were specified for priority consideration in locating and conducting demonstration projects: Saginaw River and Bay, Michigan; Sheboygan River, Wisconsin; Grand Calumet River/Indiana Harbor Canal, Indiana; Ashtabula River, Ohio; and Buffalo River, New York. In response, GLNPO initiated the Assessment and Remediation of Contaminated Sediments (ARCS) Program.

In order to develop a knowledge base from which informed decisions may be made, bench-and pilot-scale demonstrations of sediment treatment technologies were conducted as part of the ARCS Program. Information from remedial activities supervised by the U.S. Army Corps of Engineers and the Superfund program was also utilized. The Engineering/Technology (ET) Work Group was charged with overseeing the development and application of the bench-scale and pilot-scale tests.

Science Applications International Corporation (SAIC) was contracted to provide technical support to the ET Work Group. As part of this effort, SAIC was charged with conducting bench-scale treatability studies on designated sediments to evaluate the removal of specific organic contaminants. The bench-scale study using the ReTeC Thermal Desorption Technology, which is the subject of this report, took place at Star Refinery in Delaware City, DE on September 25, 1991. The specific objectives for this effort were to determine process extraction efficiencies for polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs); to conduct a mass balance for solids, water, oil, PCBs, and PAHs; and to examine process effects on metals, oil and grease, and several other parameters.


LIST OF FIGURES

  1. ARCS Priority Areas of Concern
  2. Ashtabula River Sampling Points
  3. Process Flow Diagram

LIST OF TABLES

  1. Summary of Total PCBs and PAHs
  2. Mass Balance Summary
  3. Characterization of the Ashtabula River Sediment
  4. Parameters for Analysis of ARCS Program Technologies
  5. Full-Scale Holo-FliteTM Screw Processor Specifications
  6. Analytical Methods Used by ReTeC During Phase I Testing
  7. ReTeC Analytical Matrix and Sample Identification-Ashtabula River Sediment
  8. Optimal Operating Parameters
  9. Total PCBs
  10. Feed and Treated Solids PAH Concentrations
  11. Metals Concentration in the Feed and Treated Solids
  12. Removal Efficiencies for Other Parameters
  13. PAH Concentrations in the Treated Solids, Water, and Oil
  14. PCB Concentrations in the Treated Solids, Water, and Oil
  15. Metals Concentration in the Residual Water
  16. Residual Water Characterization Data
  17. Solids Mass Balance
  18. Water Mass Balance
  19. Oil Mass Balance
  20. PAH Mass Balance

 


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