In Situ Treatment of Contaminated Soils
STAR is an innovative in situ thermal technology based on smoldering combustion, where the contaminants are the fuel. The process is sustained by the addition of air through a well to the target treatment zone and is initiated through a short duration, low energy “ignition event.” Once the process is initiated (ignited), the energy of the reacting contaminants is used to pre-heat and initiate combustion of contaminants in adjacent areas, propagating a combustion front through the contaminated zone in a self-sustaining manner (i.e., no external energy or added fuel input following ignition) provided a sufficient flux of air is supplied. Active control of the combustion front is maintained by the air supply. This efficient recycling of energy is made possible by the presence of the porous matrix (i.e., contaminated aquifer) that is being remediated.
The above ground equipment used to implement the technology is similar to that used in Air Sparge (AS) / Soil Vapor Extraction (SVE) systems and includes compressors for sub-surface air delivery, blowers for ground surface vapor collection, and vapor phase activated carbon or a thermal oxidizer for vapor treatment. The specialized equipment associated with the STAR process includes the use of 2-inch diameter, carbon steel direct push ignition wells with a stainless steel screen, temporary in-well heaters to initiate the process, and subsurface multi-level thermocouple bundles to track the combustion process.
STAR: In Situ Case Studies
Regulatory Site Closure for Coal Tar-Impacted Soils at a Former Industrial Site in New Jersey
The STAR technology was applied as the primary remedy to achieve regulatory closure at a 37-acre former industrial facility in Newark, NJ.
Treatment of Coal Tar and Creosote at a Former Manufacturing Facility in Washington
The subject site is a 22-acre former creosote manufacturing facility in Washington with coal tar and creosote contamination present.
Treatment of Petroleum Hydrocarbon-Impacted Soils at a Former Waste Oil Refinery in Taiwan
The subject site is a former waste oil refinery located in a mixed use industrial, commercial, and residential area of Chia-Yi, Taiwan.
Treatment of Navy Special Fuel Oil (NSFO) Contamination at a Naval Facility in Virginia
NSFO impacted a highly heterogeneous medium- to fine-grained sand with varying amounts of silt, coarse sand, and clay around a former tank farm.
Remediation of Petroleum Hydrocarbons at a Former Refinery in Michigan
A mixture of Gasoline Range Organic (GRO) and Diesel Range Organic (DRO) compounds have impacted a fine to very fine sand aquifer
Smoldering Combustion Treatment of PFAS-Impacted Materials for SERDP Project Number: ER18-1593
A study for the Strategic Environmental Research Program (SERDP) explored the application of STAR to treat per- and polyfluoroalkyl substance (PFAS).
Treatment of Coal Tar, LNAPL, and DNAPL at a Former Manufactured Gas Plant in Michigan
A STAR test involving a four-well ignition/air injection system was used to evaluate key full-scale design parameters.
Savron is Developing Innovative Treatment Options for PFAS and Biosolids
Savron continues to develop innovative applications of smoldering combustion. STAR shows promise for managing PFAS and biosolids.