Final Report: Encapsulating Waste Disposal Methods
EPA Contract Number:
Encapsulating Waste Disposal Methods
TDA Research Inc.
May 15, 2013 through
November 14, 2013
Small Business Innovation Research (SBIR) - Phase I (2013)
Small Business Innovation Research (SBIR)
SBIR - Homeland Security
During this SBIR Phase I effort, TDA Research, Inc. (TDA) evaluated commercially available sprayable and pour polyurethane foams (including building insulation foams) to encapsulate contaminated materials, for example, materials contaminated by a chemical or biological attack or a disease outbreak. The project objective was to determine whether the encapsulated materials could then be transported and disposed of with greater safety to personnel and with simplified regulatory requirements, thus greatly reducing the time and cost of remediation. The effectiveness of this approach was measured by demonstrating performance that lowers the threat, and therefore the category that describes the waste. Tests demonstrated that the foam forms a continuous, mechanically robust barrier over irregular objects that can contain the vapor of a volatile liquid contaminant and prevent the leaching of a water-soluble contaminant.
Toxicity characteristic leaching procedure (TCLP) testing was performed to help establish if the encapsulated waste requires a hazardous waste code. Samples of ceiling tile were saturated with a water-soluble red dye (chlorophenol red sodium salt) and then encapsulated with pour foam. We tested encapsulated materials using a modified TCLP Method 1311. At the end of the 3-week test period, spectrophotometric analysis detected no dye in any of the extraction solutions. In contrast, the positive control sample (with no foam barrier) released the dye and turned the solution red. This test demonstrated that no release of the encapsulated material was observed upon extended immersion in either acidic or neutral water.
In a second set of experiments, carpet, drywall and ceiling tile samples were contaminated with methyl salicylate (MeS), a simulant for the CW agent mustard (HD), and then encapsulated with both pour and spray foams. A permeation chamber was constructed to quantify the amount of simulant escaping from an encapsulated sample. Control experiments were performed to establish the amount of simulant captured in a carbon sorption tube, the extraction efficiency from the carbon in the sorption tube, and the recoverable amount from non-encapsulated samples in the permeation chamber. Results showed that > 99.92 percent of the MeS simulant was contained in the encapsulating polyurethane foam (no simulant was detected).
In a third series of experiments, we evaluated encapsulation of larger items with spray foam. Tests showed that even a simple consumer product spray foam will encapsulate an office chair, with a continuous, robust foam layer. An industrial spray applicator could produce more even foam, but requires a higher cost applicator.
The work performed in this Phase I SBIR effort demonstrates the feasibility of using polyurethane polymer foams to encapsulate building materials that are contaminated with a chemical warfare agent simulant. Encapsulation can protect waste treatment personnel and prevent spreading of contamination. It also can dramatically lower the cost of transport and disposal by converting a regulated hazardous waste to a non-hazardous material. For example, the cost of disposing of a 20-yard dumpster filled with contaminated material (~20,000 pounds) is $44,100. Foam to encapsulate that quantity of material costs $1,001; the cost of disposing of the resulting non-hazardous waste is $2,386. The net savings is $40,713.
Additional development and testing will be required to accumulate the information that will allow this process to be pre-approved for use in an emergency. This will include scaling up and evaluating larger spray applicators and moving all testing to larger scale and more relevant items.
encapsulation, waste disposal, chemical and biological agents