Grantee Research Project Results
Final Report: Process Development for Destruction of Hazardous Organic Compounds Including Halogens, Phosphate Esters, or Other Intractable Moities
EPA Contract Number: 68D00238Title: Process Development for Destruction of Hazardous Organic Compounds Including Halogens, Phosphate Esters, or Other Intractable Moities
Investigators: Howell, Samuel G.
Small Business: Excell Partnership
EPA Contact:
Phase: I
Project Period: September 1, 2000 through March 1, 2001
Project Amount: $69,713
RFA: Small Business Innovation Research (SBIR) - Phase I (2000) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , SBIR - Waste , Small Business Innovation Research (SBIR)
Description:
This investigation was done to confirm that laboratory findings that organic compounds could be destroyed in a unique mixture of molten sodium nitrate and sodium carbonate could be duplicated on a larger scale. This process operates at a much lower temperature (500oC) than other molten media destructions processes, and does not require exotic alloy or ceramic reaction vessels. Emissions from this type of reactor can be controlled and monitored much more readily than incinerators and probably other types of destructors. A simple, rugged reactor similar to the one designed and operated here can be easily scaled up if required, and in addition offers high flexibility in the types of wastes and turndown capability.A reactor was constructed of type 304 stainless steel, and equipped with stirring apparatus to insure good contact between the toxic material to be destroyed and the molten media, consisting of 90% sodium nitrate and 10% sodium carbonate, both naturally occurring and inexpensive reagents. The investigators realized that the reactor as designed was incapable of complete destruction in a single pass, but that the chemistry being sound, multistage reactors could be constructed to achieve almost any degree of destruction required.
Six toxic materials were injected into the reactor with varying degrees of
success. In addition to being toxic themselves, they represented structures of
other compounds of much higher toxicity such as chemical warfare agents. The
compounds were:
- Tetrachloroethylene, a solvent widely used in dry cleaning and solvent
degreasing.
- Trichlorobenzene, a surrogate for chlorinated aromatic organics; TCB might
be considered half of a PCB molecule.
- Tricresyl phosphate, uses as a flame retardant, heat transfer fluid, etc..
The phosphate structure has some similarities to chemical warfare agents.
- Dursban? (Chlorpyrophos) an insecticide, a cholinesterase inhibitor related
to "nerve gas"
- Hexachlorobenzene, a persistent chemical once widely used as a nematocide
.
- Still bottoms from dry cleaning solvent recovery which, as it contains some residual tetrachloroethylene, is considered a hazardous waste under the "Derived From" rule.
Summary/Accomplishments (Outputs/Outcomes):
Results of the investigation confirmed that the reactor destroyed every compound in its single stage configuration, with some realizing only 25% destruction, others almost 100%. The investigators know that they can adapt the chemistry to achieve much higher degrees of destruction using standard chemical engineering design practices. Operation of the reactor using several means of waste injection and reagent regeneration gave the investigators insight on engineering design changes which would enable the device to be used to destroy both liquid and solid hazardous materials.Although the equipment is inherently safer and more effective than other means of destruction such as incineration, insight was gained in incorporating fail safe and other safety precautions in operating procedures.
Conclusions:
Reactors using this chemistry can be easily fabricated of relatively inexpensive alloys, and scaled to fit almost any volume of throughput desired. A multitude of applications for the technology are readily apparent because of its flexibility and turndown ability. The first, and probably major application is for destroying dry cleaning and solvent degreasing solvent recovery still bottoms. Other, more exotic uses could be in chemical and pharmaceutical plants where the process could be used to destroy toxic chemicals or biohazardous waste. Engineering modifications could use the same chemistry to destroy infectious wastes from hospitals.Supplemental Keywords:
Treatment, Disposal, Hazardous Waste, Incineration Alternatives., RFA, Scientific Discipline, Toxics, Waste, Water, Sustainable Industry/Business, Chemical Engineering, cleaner production/pollution prevention, Contaminated Sediments, Environmental Chemistry, Chemistry, HAPS, pesticides, Analytical Chemistry, Hazardous Waste, Chemistry and Materials Science, Agronomy, Incineration/Combustion, Engineering, Hazardous, Environmental Engineering, Agricultural Engineering, halogens, contaminated sediment, incineration alternative, Polychlorinated biphenyls (Aroclors), phosphate esters, hazardous organic contaminants, destruction, polychlorinated biphenyl (PCB), toxic organic compounds, intractable moities, hazardous organic compounds, chemical destructionThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.