Solidification-Stabilization Bench Scale Tests

Solidification/stabilization is considered by the U.S. Environmental Protection Agency to be an "established" technology for the treatment of contaminated soil and sludges. The technology, which has been used to remediate about 18% of the Superfund sites in the U.S. (U.S. Environmental Protection Agency, 2004), involves mixing a reagent with the contaminated material to create a solidified mass with greatly-reduced leaching potential. Typical reagents include cement, cement-kiln dust (CKD), lime-kiln dust (LKD), fly ash, and combinations of these. Chemical additives are sometimes included to further reduce long-term leaching potential, depending on the specific nature of the contaminated material.

The terms solidification and stabilization are frequently used interchangeably, but there is a difference. Solidification involves binding hazardous constituents to the treated waste by changing the physical properties of the waste. Stabilization also binds hazardous constituents to the treated waste, but does this by changing the chemistry of the waste. The interchangeable use of the terms occurs because solidification of a waste usually also results in stabilization.

The quantities of reagent necessary to achieve solidification/stabilization are normally determined through the performance of bench-scale tests that evaluate both the physical and chemical properties of the treated and untreated waste. EarthFax Development Corporation is pleased to offer these bench-scale testing services to assist those who are planning or conducting solidification/stabilization projects. The procedures that we use were developed based on years of experience gained by our affiliate company, EarthFax Engineering, in design, laboratory testing, and field supervision of solidification/stabilization projects.

Reference

U.S. Environmental Protection Agency. 2004. Cleaning Up the Nation’s Waste Sites: Markets and Technology Trends, 2004 Edition. Office of Solid Waste and Emergency Response. EPA-542-R-04-015. Washington, D.C.

Purpose of Bench-Scale Tests

Bench-scale testing is conducted to establish the short-term construction costs, long-term maintenance costs, and long-term success of a solidification/stabilization project.

Factors Affecting Solidifcation-Stabilization

Several factors should be considered during the initial design of bench-scale tests. These factors influence the degree to which bench-scale tests are representative, workable, and cost-effective when applied to the field.

Procedures for Bench-Scale Tests

Procedures used by EarthFax Development were developed based on the extensive experience of EarthFax Engineering geotechnical engineers in the performance of bench-scale tests.

Sample Requirements and Typical Costs

Representative samples of the sludge(s) and the affected soil should be collected and placed in clean, sturdy containers (i.e., 5-gallon plastic buckets with tight-fitting lids).