&EPA United States Environmental Protection Agency EPA/540/SR-93/522 September 1994 SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION Technology Demonstration Summary ECO LOGIC International Gas- Phase Chemical Reduction Process and Thermal Desorption Unit, Middleground Landfill, Bay City, Ml ELI Eco Logic International, Inc. (ECO LOGIC) has developed a gas-phase chemical reduction process (reactor), along with a companion thermal des- orption unit (TDU), for the treatment of liquids and soils contaminated with polychlorinated biphenyls (PCBs) and other chlorinated compounds. Under the auspices of the Superfund Innova- tive Technology Evaluation (SITE) Pro- gram, and in cooperation with the city of Bay City (Michigan), Environment Canada, and the Ontario Ministry of the Environment and Energy, the EPA con- ducted the demonstration of the ECO LOGIC process at Bay City's Middleground Landfill during 28 days in October through December, 1992. This Summary was developed by EPA's Risk Reduction Engineering Laboratory, Cincinnati, OH, to announce key findings of the SITE program dem- onstration that is fully documented in separate reports (see ordering infor- mation at back). Introduction In 1986, the U.S. Environmental Pro- tection Agency's Office of Solid Waste and Emergency Response (OSWER) and the Office of Research and Development (ORD) established the SITE program to promote the development and use of in- novative technologies to clean up Super- fund sites across the country. The SITE program includes four major elements: the Demonstration Program, the Emerging Technologies Program, the Measurement and Monitoring Technologies Program, and the Technology Transfer Program. One SITE component, the Demonstra- tion Program, provides reliable engineer- ing, performance, and cost data on selected hazardous waste technologies. This information, used in conjunction with other data, enables EPA and state deci- sion-makers to select the most appropri- ate technology for Superfund cleanups. The three-part SITE demonstration of the ECO LOGIC process was conducted at the Middleground Landfill in Bay City, Printed on Recycled Paper ------- Ml, during 26 days in October through December, 1992. The first part (Test Con- ditions 1 and 3) evaluated only the reactor system as it processed liquids; the sec- ond part (Test Condition 2) evaluated the TDU in combination with the reactor; the third part consisted of a 72-hr engineering performance test. EPA established the following program objectives: • Demonstrate at least 99.9999% de- struction and removal efficiency (DRE) for polychlorinated biphenyls (PCBs). • Demonstrate at least 99.99% destruc- tion efficiency (DE) for perchloroeth- ylene (PCE), the tracer in the liquid feedstock, and hexachlorobenzene (HCB), the tracer in the solid feed. • Ensure that no dioxins or furans were formed. • Characterize products of incomplete combustion (PIC) in emissions. • Characterize hydrogen chloride (HCI) in emissions. • Document compliance with Michigan Department of Natural Resources (MDNR) air permit conditions. • Characterize criteria air pollutant emis- sions. • Document compliance with Toxic Sub- stances Control Act (TSCA) permit requirements. • Validate key cost assumptions used in process economic analyses. • Characterize effluents and residual streams relative to disposal require- ments. • Determine the suitability of the re- formed gases for reuse/resale. • Demonstrate system reliability. • Develop a system mass balance, in- cluding metals. • Characterize critical process scale-up parameters. • Validate the performance of ECO LOGIC'S on-line Chemical lonization Mass Spectrometer (CIMS). • Document system operation during test runs. Technology Description The ECO LOGIC gas-phase chemical reduction process (reactor) treats liquid organic hazardous waste in a hydrogen- rich atmosphere at approximately 900°C (1,650°F) temperature and ambient pres- sure to produce a high BTU reformed gas product. The process is well suited for aqueous waste streams as water acts as a hydrogen donor to enhance the reduc- tion reaction. The reaction products in- clude HCI, from the reduction of chlorinated organics, such as PCBs, and lighter hy- drocarbons, such as methane and ethyl- ene, from the reduction of straight-chain and aromatic hydrocarbons. The absence of free oxygen in the reactor inhibits di- oxin formation. The ECO LOGIC reactor can be com- bined with their patented TDU, which treats organic hazardous wastes in solid and liquid media. The TDU processes soil by desorbing organics at 500 to 600°C (930 to 1,100°F) using a molten metal bath as a heat transfer medium. Organics are de- sorbed into a hydrogen-rich carrier gas. Most volatile metals found within soils will be dissolved into the molten metal bath, some will pass to the reactor with the carrier gas, and the remainder will stay in the treated soil. Nonvolatile metals remain in the treated soil; quench water cools the soil before disposal. The hydrogen-rich carrier gas conveys the desorbed organ- ics to the reactor (Figure 1), where they are treated in a gas-phase chemical re- duction reaction to produce reformed gas. Figure 2 illustrates the ECO LOGIC pro- cess in a schematic diagram of the dem- onstrated unit. For the reactor demonstration, a heat exchanger evaporated contaminated aque- ous feedstock to form steam and a con- centrated heated liquor. Atomizing nozzles sprayed the heated liquor, with associ- ated particulates, into the reactor. A sepa- rate pump sent PCB-rich oils directly to the reactor through other atomizing nozzles. Compressed, hydrogen-rich, re- circulating gas passed through a gas-fired heat exchanger and entered the top of the reactor tangentially. The tangential entry swirled the fluids to provide effective mix- ing. As indicated in Figure 1, the swirling mixture traveled downward in the annulus formed by the reactor wall and the central ceramic-coated steel tube, past electrically heated bars. These bars heated the mix- ture to 900°C (1,650°F). At the bottom of the reactor the mixture entered the tube, reversed direction, and flowed upward to the outlet of the reactor. The reduction reactions occurred as the gases traveled from the reactor inlets to the scrubber inlet. After quenching, the gases flowed through a scrubber where contact with water removed HCI and fine particulates. A large water-sealed vent, acting as an emergency pressure relief duct, passed scrubber water to a tank below. A pump recirculated the scrubber water through an evaporative cooler to reduce its tem- perature to 35°C (95°F). Caustic and rnake-up water, added to the scrubber liquor, maintained HCI removal efficiency. The scrubber produced two effluent streams, sludge and decant water. The reformed gas exiting the scrubber contained excess hydrogen, lighter hydro- carbon reduction products such as meth- ane and ethylene, and a small amount of water vapor. Approximately 95% of this hydrogen-rich gas was reheated to 500°C (930°F) and recirculated back into the re- actor; about 5% of the gas served as supplementary fuel for a propane-fired boiler used to produce steam. The boiler, which burned a mixture of propane and reformed gas, generated the only air emis- sions from the process. When treating wastes containing highly concentrated organics, the process gen- erates excess reformed gas. The system operator can elect to compress the ex- cess reformed gas and store it for later use or analysis. Site Preparation The demonstration-scale reactor was 2 m (6 ft) in diameter and 3 m (9 ft) tall, mounted on a 15 m (45 ft) drop-deck trailer. The trailer carried a scrubber sys- tem, recirculation gas system, and an elec- trical control center. A second trailer held a propane boiler and a waste preheating vessel. The TDU traveled on a third flat- bed trailer. The ECO LOGIC system requires a fairly level area, approximately 120 ft x 180 ft, for the processing and auxiliary equip- ment. ECO LOGIC arranged the reactor, TDU, and support equipment trailers in parallel; they piped and wired the system components together. Six additional trail- ers provided office space for EPA, sam- pling and analysis facilities, onsite laboratories, ECO LOGIC process con- trols, and a maintenance shop. Storage tanks held nitrogen, propane, hydrogen, oxygen, reformed gas, and pro- cess residuals. Existing utility connections provided electrical power and water. Re- covery wells, installed in previously lo- cated underground pools, provided feedstock for the demonstration. Technology Testing ECO LOGIC designed the TDU/reactor process to simultaneously treat 4 tons/ day of waste oil, 10 tons/day of wastewa- ter, and 16 tons/day of soil, depending on the nature of the contaminants, their de- gree of chlorination, and their water con- tent. The actual demonstration test treated approximately 0.2 ton of waste oil, 2.9 tons of wastewater, and 1.1 tons of soil, all contaminated with PCBs. On average, the wastewater contained 3,757 ppm PCBs; soil, 627 ppm; and oil, 254,000 ------- THERMAL DESOfiPTlON UNIT 35°C Condensate Gas booster Scrubber water make-up and caustic 180°C Stack gas Boiler ^ \~\ Sfeam -^ 3 fc < Hydrocarbon gas (5%) Combustion air Figure 1. ECO LOGIC gas-phase chemical reduction process and thermal desorption unit ------- To scrubber Waste injection ports Reactor steel wall Fibreboard insulation Refractory lining Electric heating elements Ceramic-coated central steel tube To grit box Figure 2. ECO LOGIC Process schematic diagram of the demonstrated unit. ppm. The wastewater and waste oil were spiked with PCE and the soil with HCB, both tracer compounds to test Resource Conservation and Recovery Act (RCRA) destruction efficiencies. ECO LOGIC first performed a series of shakedown tests to establish optimum sys- tem performance. Two liquid tests (Condi- tions 1 and 3) and a soil test (Condition 2) followed. Each test condition consisted of three runs, except Condition 2, which con- sisted of two runs. The demonstration also included a 72-hr, continuous-operations reliability test. The program maintained optimal operating parameters while vary- ing the media and contaminant concen- trations in the feedstock. Table 1 summarizes the operating conditions for each test. EPA collected extensive samples from points around the system components and stored or logged important data on oper- ating and utility usage. Laboratory analy- ses provided information on the principal process streams: desorbed soil, reactor grit, scrubber residuals, reformed gas, and boiler stack emissions. EPA evaluated these data against established program objectives to determine the capability of the process to treat the designated waste. Demonstration Results Table 2 summarizes the results for the wastewater and waste oil tests; Table 3, the results for the soils tests. In general, the reactor system met all the Condition 1 and 3 objectives except benzene emis- sions. Condition 2 met all objectives ex- cept DE for the tracer compound HCB. The Technology Evaluation Report, avail- able from NTIS, contains detailed data from all three conditions. (See information at back.) Estimated Treatment Costs The twelve cost categories established for the SITE program formed the basis for the detailed cost analysis. Costs relate to the demonstration-size reactor unit, pro- cessing an average of 2.2 kg/min, as op- erated at the Middleground Landfill. Based on an economic analysis contained within the Application Analysis Reports, the esti- mated costs for treating liquid wastes simi- lar to those at the Bay City site range from $1,670/ton (80% utilization rate) to $2,000/ton (60% utilization rate). The most important element affecting cost is labor (52% of cost), followed by site preparation (15%), supplies (12%), and start-up/mobi- lization (12%). The estimated costs for treating soils with the combined TDU/re- actor system range from $500/ton (80% utilization rate) to $630/ton (60% utiliza- tion rate). Conclusions Based on the program objectives, the demonstration confirmed the feasibility of the gas-phase chemical reduction process for treating PCBs and other chlorinated organic compounds, for producing a fuel gas from PCB-contaminated soil and liq- uids, and for providing environmentally acceptable air emissions. Reactor System In general, ECO LOGIC'S reactor sys- tem effectively destroyed PCBs, reducing them to lighter hydrocarbons. Stack emis- sions generally met stringent regulatory levels; however, benzene concentrations in the stack gas and scrubber liquor re- quired close monitoring. The scrubber li- ------- quor required disposal as a RCRA waste or recycling through the system for addi- tional treatment. TDU/Reactor System The TDU did not perform to design specifications. EPA categorized the TDU test data as a system proof-of-concept rather than as a comprehensive evalua- tion of a fully developed unit. The test data indicated that the TDU, as presently configured, achieved desorption efficien- cies at the expense of throughput. In ad- dition, ECO LOGIC experienced material handling problems with the TDU feed. The combination of material handling problems and inadequate organics desorption indi- cated a need for further development. The test data have identified system strength and targeted areas that require improve- ments. Nevertheless, the demonstration did show that ECO LOGIC'S TDU can desorb PCB contaminants. Treatment of the TDU- produced desorbed gas in the reactor pro- duced stack emissions that generally met stringent regulatory levels. The reformed gas composition resembled coal-gas fuel; the scrubber liquor required disposal as a RCRA waste. In commercial operations, this liquor could be recycled through the system. Table 1. Operating Conditions Summary Component Parameter TDU Reactor Scrubber Recirculating fan Vaporizer Bath temperature Dome temperature Gas temperature Pressure Temperature Pressure Resident time Inlet temperature Outlet temperature Water pH Differential pressure Flow rate Gas pressure Temperature Pressure Measure (°C) (°C) (°C) (in. H20) (°C) (in. H20) (sec.) (°C) (°C) (in. H20) (dm) (in. H20) (°C) (psi) 1 N/A N/A N/A N/A 892 1.8 8 546 33 8.78 11.6 110 6.5 148.3 51.8 Condition 2 624 612 449 2.25 890 2.46 7.7 504 32 8.42 9.1 110 5.2 N/A N/A 3 N/A N/A N/A N/A 933 1.8 6.1 527 32 9.32 7.81 110 0.66 149 51.4 ------- Table 2. Summary of Results for Condition 1 (Wastewater), and Condition 3 (Waste Oil) Tests Results Objective Demonstrate ORE for PCBs: 99.9999% Met X Not Met Range 99.9999% to 99.99999% Conclusions Good destruction. Demonstrate DE for PCE: 99.99% X Ensure no formation PCDD/PCDF X Characterize PIC emissions X Characterize HCI emissions X Document MDNR air permit X compliance Characterize criteria air pollutants X Document TSCA permit compliance X Validate key cost assumptions X Characterize effluents and residuals X Determine suitability of reformed X gases for reuse/resale Demonstrate system reliability X Develop mass balances X Characterize scale-up parameters X Validate CIMS Document system operation X 99.99% PCDD DE: 63.05% to 98.36% PCDFDE: 99.91% to 99.98% Benzene: 73 to 113pg/dscm 0.659 to 0.807 mg/dscm; 147.6 to 173.3 mg/hr; 99.96% removal Benzene: 48.5ng/dscm Throughput reliability: 20 to 55% of design. System availabil- ity:24% Good destruction. No net PCDD/PCDF formation. PICs characterized; benzene emissions exceeded regulatory limit. Acceptable emissions. Air permit compliance documented; benzene emissions exceeded MDNR conditions. Easily met permit conditions. Met permit conditions. Cost elements identified. Organics destroyed; metals partitioned to scrubber effluents; after further treat- ment, scrubber liquor may be suitable forPOTW. Closely matched composition of other commercial fuel gases. Process reliability requires improvement. Generally good closures, except for certain metals. Characterized. May reflect data trends useful for process control. Data available for commercial scale-up. ------- Table 3. Summary of Results for Condition 2 (Soil) Test Objective Demonstrate ORE for PCBs: 99.9999% Demonstrate DE for HCB: 99.99% Ensure no formation of PCDD/PCDF Characterize PIC emissions Characterize HCI emissions Met X X X X X Results Not Met Range 99.9999% 72. 13 to 99.99% PCDD DE: 42.5% to 99.45% PCDFDE: 54.6% to 98.12% 0.68 mg/dscm; 150 mg/hr; 99.98% removal Conclusions Requirements met. Inefficient desorption from soil in Run 1. No net PCDD/PCDF formation. Emissions characterized. Acceptable emissions. Document MDNR air permit X compliance Characterize criteria air pollutants X Document TSCA permit compliance Validate key cost assumptions X Characterize effluents and residuals X Determine suitability of reformed X gases for reuse/resale Demonstrate system reliability X Develop mass balances X Characterize scale-up parameters X Validate CIMS Throughput reliability: 4% to 21.2% of design. System availability:24% Air permit compliance documented. Easily met permit conditions. Not applicable. Cost elements identified. Organics destroyed; metals partitioned to scrubber effluents; after further treatment, scrubber liquor may be suitable for POTW. Closely matched composition of other commercial fuel gases. Process reliability requires improvement. Generally good closures, except for certain metals. Characterized. May reflect data trends useful for process control. Document system operation Data available for commercial scale-up. ------- The EPA Project Manager, Gordon M. Evans, is with the Risk Reduction Engineer- ing Laboratory, U.S, Environmental Protection Agency, Cincinnati, OH 45268 (see below). This summary presents findings from two volumes: "Technology Evaluation Report: ECO LOGIC International Gas-Phase Chemical Reduction Process, Bay City, Ml," which discusses the results of the SITE demonstration; "Technology Evaluation Report: ECO LOGIC International Gas-Phase Chemical Reduction Process, Bay City, Ml, Appendices." Both volumes may be obtained by asking for Order No. PB95-100251, cost $52.00 (subject to change). These volumes will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 Two related reports, entitled "Applications Analysis Report: ECO LOGIC International Gas-Phase Chemical Reduction Process, The Reactor System" and "Applications Analysis Report: ECO LOGIC International Gas-Phase Chemical Reduction Pro- cess, The Thermal Desorption Unit," discuss the applications of the demonstrated technology. The EPA Project Manager can be contacted at: Risk Reduction Engineering Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 Official Business Penalty for Private Use $300 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 EPA/540/SR-93/522 ------- |