vvEPA United States Environmental Protection Agency EPA/540/M5-89/011 October 1989 SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION Demonstration Bulletin Solidification/Stabilization Process Chemfix Technologies, Inc. TECHNOLOGY DESCRIPTION:The Chemfix tech- nology is a patented solidification/stabilization process for treating hazardous wastes. Proprietary reagent additives may include soluble silicates and silicate- setting materials. The process is designed as a continuous operation capable of treating large quantities of wastes rapidly. The products of the process are intended to be stable, friable materials with good erosion resistance and low permeabilities. In addition, the process is intended to treat the material without a large increase in volume. After the contaminated material is excavated and screened to remove pieces larger than 1 inch, a conveyer belt moves it from the feed hopper to the weight feeder, where it is measured. The homog- enizer mixes the wastes with water to achieve the desired moisture content. The wetted material then moves to a Chemfix-designed pug mill, where it is blended with the proprietary reagents. After the material is thoroughly mixed, it is discharged and allowed to harden. The final product is a solidified mass. WASTE APPLICABILITY: This process is designed to treat soils, sludges, and waste waters. It has been used for a variety of industrial wastes contaminated with heavy metals and organic compounds with high molecular weight. Hopp«r With Ev»n F**d*r Conv«yor WMcr Supply frf rtqulrad) Ajarmtand Control Pan* No. 1 Chut* to Truck Loading Area Figure 1. High solids handling system block process flow diagram. ------- DEMONSTRATION RESULTS: EPA and the devel- oper demonstrated this solidification/stabilization process at the Portable Equipment Salvage Company site in Clackamas, Oregon during March, 1989. The site had been used for the scrapping and recycling of transformers and metal equipment. Although the soil at the site is contaminated with a variety of pollutants, the contaminants of concern for this demonstration were lead, copper, and PCBs because they were found in the highest concentrations in the preliminary round of sampling. The equipment utilized was capable of processing soils at a rate of up to 100 tons per hour. Several leaching and extraction tests were conducted on products of the solidification/stabilization process to indicate the long-term stability of the processed material. The toxicity characteristic leaching procedure (TCLP) extracts from processed wastes contained lead in concentrations 94 to 99 percent less than in leachate extracts of untreated wastes. Table 1 presents a summary of the results of the TCLP tests for lead and copper. No conclusions could be derived regarding PCB immobilization since the concentrations of PCB in the initial TCLP extracts were extremely low. PCB extrac- tion data does show evidence of partial dechlorination of the PCBs. However, the phenomenon may not be due to the solidification/stabilization process only. The wet/dry and freeze/thaw durability tests were very good, showing little or no weight loss after 12 cycles. The unconfined compressive strength (UCS) at 28 days ranged from 27 to 307 psi. Permeability of the treated material ranged between 1x10-6 cm/sec and 6.4 x 10'7 cm/sec. Table 2 presents a summary of these results of the physical tests and other chemical tests. Other results of the demonstration include the following: • The volume increase in the excavated waste material after treatment ranged from 20 to 50 percent. The air monitoring data suggest that there was significant volatilization of PCBs during treatment process. no the A Demonstration Report describing the complete demonstration will be complete in early 1990. FOR FURTHER INFORMATION: EPA Project Manager Ed Barth U.S. EPA Risk Reduction Engineering Laboratory 26 West Martin Luther King Drive Cincinnati, OH 45268 513-569-7669 (FTS: 684-7669) Table 1. Mean Concentrations of Concern from Chemfix Demonstration Area A Lead Copper AreaC Lead Copper Area E Lead Copper Area F Lead Copper Untreated Waste (Total) 21 ,000 mg/kg 18,000 mg/kg 140,000 mg/kg 18,000 mg/kg 92,000 mg/kg 74,000 mg/kg 1 1 ,000 mg/kg 33,000 mg/kg TCLP From Untreated Waste 610 mg/L 45 mg/L 880 mg/L 12 mg/L 740 mg/L 120 mg/L 390 mg/L 120 mg/L TCLP From Treated Waste < .05 mg/L 0.57 mg/L 2.5 mg/L 0.54 mg/L 47 mg/L 0.65 mg/L 0.10 mg/L 0.60 mg/L Percent Reduction of TCLP Extractable Metal 99 99 99 95 94 99 99 99 Table 2. Physical and Chemical Properties of Treated and Untreated Wastes from Area C of Chemifx Demonstration AreaC Eh (millivolts) Conductivity (umhos/cm) PH 28 -day UCS (psi) Wet/dry stress weight loss Freeze/thaw stress weight loss Permeability (cm/sec) Untreated Wastes 290 130 6.6 N/A N/A N/A 10-4 to 10-« Treated Wastes 24 3200 11.3-11.5 27-307 <1% <1% 10-6 tO TO'7 ------- |