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Decontamination/Isolation of Contaminates 



1. Bioremediation - Sediments are first analyzed to determine 

 if there are nutrient or oxygen deficiencies which inhibit the 

 growth of naturally occurring organisms that break down 

 pollutants into harmless constituents. "Fertilizers" can be 

 applied to encourage the growth of these microbes, or the 

 sediment can be inoculated with a new strain. Whether to dredge 

 the sediments first is an issue, as is the long-term 

 effectiveness of this expensive treatment. Bioremediation has 

 been successful in treating complex organic compounds (except 

 PCBs) , as well as metals, on a small-scale basis. 



2. Incineration - Once contaminated sediments have been 

 dredged and the water removed, the resulting material can be 

 incinerated to destroy the pollutants. This practice is growing 

 more common, and EPA has issued standards for incinerators which 

 require limits on emissions, and combustion efficiencies of 99.9 

 percent. PCBs must be destroyed 99.9999 percent of the time. 

 Continuous monitoring is needed to ensure these standards. 

 Incineration works best on organic contaminates, as it may 

 oxidize metals in sediments and make them more available to 

 living organisms. 



Another incineration-like process, the Taciuk process, uses 

 heat to separate organic contaminants from sediments. Pyrolysis 

 applies high temperatures without combustion to degrade PCBs and 

 other organics. Costs for this method of decontamination, 

 including dredging, transport, treatment, and disposal, amount to 

 $900 per cubic meter. 



3. Vitrification - A combination of hardening and 

 incineration, vitrification involves the channeling of an 

 electric current through sediment to bind it into glass-like 

 material. The intense heat also destroys PCBs and other organic 

 contaminates. This has been used on a small scale with highly 

 contaminated sediments at Superfund sites. The sediment must be 

 dredged first, and poisonous gases from the vitrification process 

 collected. Cost estimates are $60 per cubic meter. 



4. In-Line Treatment - As used by the Japanese, in-line 

 treatment involves the m-take of contaminated sediments in large 

 pipes. Pollutant binders are then injected into the pipe and the 

 resulting "clumps" of contaminates removed and treated. 



5. Centrifuging - Because pollutants adhere to the finer 

 portions of sediment, contaminated material can be loaded into 

 large cyclones or centrifuges, and the coarser, cleaner materials 

 extracted. The much smaller portion of polluted particles can 

 then be decanted and treated. Costs for this technology (now in 

 use on a small scale) is estimated to be $100-200 per cubic yard. 



6. Propane Extraction System - This method uses propane gas 

 converted to a liquid by pressure to dissolve organic pollutants. 

 The propane and its load of contaminates are separated from the 

 inert solids. Releasing the pressure converts the propane back 

 into gas which is recaptured and used again. The isolated 



