A Final Word About Product Quality
As preposterous as the statements about flooding, any suggestion that the material being placed at the site for the cap is "highly contaminated" is equally false – another scare tactic by people who do not want the site cleaned up.
The Department and the LSRP worked on the acceptable limits of the product for months, reviewing the existing data, the protocol for placement and the maximum limits allowed by various methods the Department uses to determine acceptability. This exhausting review led to an extremely comprehensive understanding of the process and product to be used and how it relates to the new regulations and procedures adopted under the new LSRP program. The exercise was extremely helpful for all parties.
Soil Safe engages the most rigorous review of any Class B facility in the state and documents the characterization data on real time basis for review by inspectors throughout the project and beyond.
Characterization and tracking of incoming soil and product follows a protocol which is described as follows:
Even though the property is and shall forever be deed restricted for non-residential use, all of the product used to construct the cap will meet the Department's residential limits with the possible exception of six compounds, known as PAHs. These compounds are found virtually everywhere on the site already at concentrations up to 300 times the non-residential standards. They are also found in asphalt and in soil all over North Jersey, Staten Island and the New York Metropolitan areas.
If these compounds exceed residential standards in the product underlying the final cap material, the exceedence will be a small fraction of what exists on the site now and bound in a soil cement matrix for added measure. These concentrations are in keeping with Department regulations and have been reviewed with, and agreed to by, the Department. All of the cap material will be tested and certified and will be as safe or more safe than virtually all soils found in these areas. And finally, the product to be placed on the surface of the site will meet residential remediation standards for all constituents.
What is the purpose of mixing the soil with cement?
Soil Safe uses a Solidification/Stabilization (S/S) process. S/S is a well-known and thoroughly documented category of treatment methods for soil and soil-like materials containing contaminants. It is effective in changing the materials' physical and chemical characteristics, and is considered a Best Demonstrated Available Technology (BDAT). The USEPA describes the general objectives of S/S ( ):
• Reduce contaminant mobility or solubility
• Improve the handling and physical characteristics of materials by producing a solid with no free liquid
• Decrease exposed surface areas across which transfer or loss of contaminants may occur
Solidification refers to the process of adding a binder to a granular material to produce a solid. Solidification primarily changes the physical characteristics of the material - it may or may not chemically bind the contaminants, but will reduce their mobility by incorporating them into the solid. Stabilization refers to converting a contaminant into a more chemically stable form through processes such as chemical reactions with the binder, change in solubility by modifying pH, etc. Collectively, S/S does both.
If the material to be processed has large particles, it must be screened or sized to a maximum particle size. The moist material is then mixed with a binding agent. The most common agent used is cement, and the most common mixing equipment is conventional paddle mixers or pugmills. The moisture and mixing starts a chemical reaction with the binding agent, and the S/S process starts.
S/S works extremely well for the kind of materials to be recycled at the Carteret site, and parameters of the process can be modified to produce a final product to meet precise specifications for its intended use.
The main characteristics addressed by S/S in this instance are permeability and shear strength. While it does occur, contaminant mobility is not a primary objective because the potential contaminant levels are already very low. The primary objectives are to reduce permeability and increase shear strength so the material can be used to cap the soft, unstable sludge in the impoundments.
The process to be used in Carteret reduces permeability by a factor of 50 to 200x, and increases the strength by a factor of 10 to 20x. Its effectiveness has been repeatedly demonstrated over the past 20 years, and the material gets stronger over time.
1) Source: EPA/600/R-09/148 – Technology Performance Review: Selecting and using S/S Treatment for Site Remediation - Nov. 2009 http://www.epa.gov/nrmrl/pubs/600r09148.html which also provides typical S/S performance specifications.
The other locations that have been remediated have already developed thriving habitats for terrestrial and semi-aquatic species, re-establishing a vigorous ecological environment.
“Experience with this engineered fill product on other capping sites in New Jersey has shown that the Soil Safe Product achieves the consistent geotechnical properties necessary for this project. The product has consistently met an AASHTO A-2-4 classification, can be readily compacted to 92-95% of modified Proctor and when properly placed and compacted achieves permeability in the order of 1 x 10-6 cm/sec.” - NJ Department of Environmental Protection