Method and apparatus for the removal of excess sodium reagent and

Abstract

A method for removing the excess sodium and byproducts of reaction which occur during the destruction of PCBs from oil. A predetermined quantity of water is mixed with the decontaminated oil and the byproducts, which include sodium chloride and polyphenyl polymer, to form sodium chloride and sodium hydroxide. Centrifuging removes most of the oil from the remaining aqueous mixture which then is agitated and treated with carbon dioxide gas to form less hazardous sodium carbonate and sodium bicarbonate. Any excess carbon dioxide gas is vented to the atmosphere and the sodium carbonate and sodium bicarbonate is collected into containers for disposal. Small amounts of oil remaining in the aqueous waste mixture that is discharged from the centrifuge is decanted from the remaining material in a waste separator due to its lighter specific gravity. A pump intermittently injects waste from the waste separator into a converter where it reacts with the carbon dioxide gas. A corresponding amount of the treated waste is ejected from the converter and collected in waste containers. A releif valve on the discharge end of the converter is adjusted to a valve lower than a check valve in the carbon dioxide gas incoming line to ensure a sufficient supply of gas in the converter. A pump continuously agitates and recirculates the waste material in the converter to ensure a thorough mixing and reaction with the carbon dioxide gas.