Characterization and Treatment of By-Product Waters from Selected Oil Shale Retorting Tests.

摘要

Oil shale retorting by-product waters from four surface retorting pilot tests and three simulated modified in situ retorting pilot tests were characterized for inorganic and organic chemical constituents. Eastern and western US shales were retorted for the tests. Ammonium bicarbonate, ammonium thiosulfate, various pyridines, and phenolic species were among the principal contaminants in the retort by-product water. The water also contains total dissolved solids up to 7000 ppM. When steam was used as a source of heat for oil shale retorting, the condensate that formed diluted the concentrations of contaminants, especially mineral dissolved solids, in the by-product water. The combined water treatment steps of hot-gas stripping followed by wet air oxidation at 600/degree/F (315/degree/C) and 2000 psi for 30 minutes removed 99% of the total organic carbon in the retort by-product water, producing a colorless and almost odor-free water. In one treatment test, the total organic carbon (TOC) was reduced from 3400 mg/L to less than 20 mg/L, with the 20 mg/L TOC remaining consisting of low molecular weight carboxylic acids. Only a partial TOC reduction occurred, with various alkylpyridines remaining as residuals when the retort waters were subjected to wet air oxidation as the only treatment step. Electrocoagulation as an initial water treatment step removed less than 30% of the TOC. 10 refs., 4 figs., 12 tabs. (ERA citation 14:014348)