Thermal Processing of Contaminated Soils and Sludges

SafeSoil's patented mobile thermal desorption system, the TDS-10, is the final solution for remediating contaminated soils, sludges or other material contaminated by volatiles and semi-volatiles.  The TDS-10 utilizes radiant heat to volatilize and separate the volatiles and semi-volatiles from the contaminated material, thereby rendering the material uncontaminated or below regulatory action limits.  The previously contaminated material is able to be retained on its original location eliminating costly backfilling, hauling, and the long term liability associated with landfilling.  The reduction of material taken to landfills is increasingly becoming a primary goal of environmental regulatory authorities.

The design of the TDS-10 unit consists of three distinct processes:  1) the movement of contaminated material through the Primary Treatment Unit (PTU), 2) the heat transfer process to volatilize and separate the contaminants from the material in the PTU, and 3) the removal of the volatized vapors.

The contaminated material is introduced into the TDS-10 unit via a conveyor belt system that empties into the input end of the PTU.  Once inside the unit, the contaminated material is moved through the PTU to the discharge end of the system.  The PTU provides a heat source which separates and volatilizes the contaminants from the material.  The heat source for the PTU is the heater unit which is filled with heat transfer fluid and is fueled by propane or natural gas.  The heater is activated to bring the temperature of the heat transfer fluid to temperatures ranging from 400 to 750 degrees Fahrenheit.  The heat transfer fluid is circulated through the system, including the PTU.  The heat transfer fluid is pumped through the interior of the PTU as well as the exterior jacket, in order to provide a large surface area for heat transfer between the contaminated material and the PTU.  The PTU consists of a patented process that conveys the soil from the input end to the discharge end of the PTU.  The processed material is removed from the PTU where a conveyor system carries the remediated, clean material to a stockpile.

The volatilized contaminants (vapors) are removed from the PTU, and enter a knockout chamber where most of the remaining moisture is removed.  Some water which may accumulate in the knockout chamber is fed back to the system.  The vapors then enter a baghouse where they are filtered for particulates and are either fed into a custom-designed Secondary Combustion Chamber (SCC) where the volatiles will supplement the fuel for the SCC, or fed into a Condensing Unit (CU) for recycling.  In the case where the vapors enter the SCC, the SCC provides a minimum of 2.5 seconds of residence time to completely combust the volatiles.  Air emissions are substantially below regulatory levels.  In contrast to a rotary kiln direct fire incineration process, the TDS-10 has no open flame contact with the contaminated material.  In many states, because of the excellent quality of the TDS-10's air emissions, along with the no open flame radiant heat process, there are no air permitting requirements.

The soils are handled, stored, and treated in accordance with all applicable regulations.  After processing, the materials are analyzed for BTEX and TPH by obtaining a composite sample for each 50 cubic yards of contaminated material.  The target level consists of 30 ppm TPH and 10 ppm total BTEX or below.  Materials are stockpiled and marked on site until the analytical chemistry results are known.

The Destructive Removal Efficiency (DRE) of the SafeSoil's Patented Process is related to several factors.  These factors include operating temperature of the PTU, material residence time in the PTU, moisture content of the material, contaminant concentration(s), contaminant properties and the type of contaminated material.

The SafeSoil's Process is state-of-the-art technology in the remediation of contaminated soils, sludges or other contaminated material.  The process was designed for the remediation of materials in the oil field.  SafeSoils TDS-10 unit is the proven cost-effective solution to large or small on-site remediation problems.

Stack Emissions

Metco Environmental, Inc. of Dallas, Texas conducted a source emissions survey of SafeSoil's patented mobile remediation equipment (the TDS-10) on August 7 and 8, 1991.  The following is the report:

Remediation Results

The following table sets forth the results of remediation contracts completed in 1991.

Technical Data