STARx Applicability

How is STARx applied?

STARx can be applied with either a reactor system or a soil pile system.  Reactor systems have a small footprint and can be easily integrated into existing infrastructure, but the processing rate will be limited by the volume of the reactor.  Soil pile systems are best for large volumes of materials at sites where space is not limited.  For both systems, the designs are 100% modular, so that processing rates can be increased by adding reactors or increasing the number or dimensions of the soil pile.  


How much does STARx cost?

Capital costs depend on the type of system employed (reactor versus soil pile) and operating costs are highly dependent on the volume of materials and the rate of material treatment.  As with STAR, the self-sustaining nature of the process means that the energy requirements for STARx are minimal.  Therefore, regardless of the type of system used or the volumes being treated, STARx is far more cost effective than incineration or thermal desorption and can be set up on site to avoid transportation costs. 

What are the key cost factors?

Cost are driven by processing rate requirements and the volume of materials to be treated. 

STARx Evaluation Process

How do I know if STARx is appropriate for my Site?

A quick treatability test is all that’s required to determine if STARx is an appropriate solution for a site. 


What is the STARx treatment efficiency?

STARx is capable of destroying greater than 99.9% of contaminant / waste mass.  However, mass destruction efficiencies are dependent on processing rate requirements, as the fraction of mass volatilized (and captured for subsequent treatment) is a function of air flow rate.  If treating soils, STARx is capable of completely removing all contaminant mass. 

Are there secondary contamination issues? 

Metals will not be remediated by the STARx process (other than mercury which can be volatilized, captured, and treated).  The metals that remain in soil may undergo some mineralogical changes and recent work at the University of Strathclyde is considering this issue. 

Engineering Controls

How quickly can the reaction be terminated?

We have demonstrated hundreds of times in the lab and in the field that terminating the injection of air terminates the smoldering reaction instantly. 

Does pyrolysis or carbonization also occur? Can they be controlled if present?

Smoldering is a two-step combustion process: pyrolysis and oxidation.   Therefore, pyrolysis does occur in all smoldering reactions; however, as long as sufficient oxidant (air) is injected, the process will continue on to the oxidation step to complete the combustion reaction. 

How important are vapor controls?

Vapor controls will be required at most sites for volatile organic carbons and carbon monoxide for reasons of health and safety and permitting.


What permits may be required?

Air discharge permitting (primarily benzene and carbon monoxide).

What has to be monitored? And for how long?

Typically we monitor for benzene and carbon monoxide.  The duration / frequency of monitoring will depend on the jurisdiction for the permit.


Are there issues with vapors?

Data collected to date reveal that vapors from the STARx process are primarily carbon dioxide and water with smaller quantities of carbon monoxide. Depending on the contaminant being treated, some much lower quantities of contaminant vapors may be generated during the combustion process; however, these are easily managed using standard vapor collection and treatment technologies (e.g., activated carbon or thermal oxidation).

What are the key human health exposure issues? 

The primary human health exposure issues relate to emissions.  Typically, a small fraction (<1%) of remediated mass is released as volatile components for subsequent capture and treatment (primarily BTEX and naphthalene); in addition, the smoldering combustion process converts contaminants to carbon monoxide and carbon dioxide.  Therefore, the vapor collection and treatment system must be designed to mitigate any potential human health exposure issues related to volatile vapors and carbon monoxide. 

What analysis has been done to date on collected vapors?

We traditionally analyze vapors for combustion gases (carbon monoxide and carbon dioxide) to verify the occurrence of smoldering and to estimate the mass of contaminants destroyed by the process, volatile organic compounds (VOCs), and semi-volatile organic compounds (SVOCs).  The most common and largest proportion of compounds detected in vapors include benzene, toluene, ethylbenzene, xylene, and naphthalene (i.e., light hydrocarbons). 

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