Purifying oil shale retort water
AssigneeUniversity of Southern California
InventorsTeh F. Yen, John E. Findley
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Abstract
Anaerobic bacteria, e.g., of the Desulfovibrio family, are added to oil shale retort water producing an increase in cell biomass and reducing sulfate ions present to sulfide. The cell biomass is aggregated into a flocculent mass and removed. The sulfide can be oxidized and recycled to neutralize the retort water. Oxidation of sulfide to sulfate can be accomplished by addition of aerobic bacteria, e.g., of the Thiobacillus family.
Claims33
A process for purifying oil shale retort water having a substantial amount of organic content, said retort water having sufficient inorganic components, including sulfate, to enable the growth of anaerobic bacteria, comprising:
- (a) lowering the alkalinity of said retort water to a pH in the range of about 6.5-7.5 and adding to said retort water anaerobic bacteria for reducing said sulfate to sulfide, said bacteria being capable of growth by utilizing said organic content;
- (b) producing in said retort water under anaerobic conditions a growth of cell biomass of said bacteria aggregated into a flocculent mass, and reducing said sulfate to sulfide;
- and thereafter
- (c) removing said aggregated cell biomass from said retort water;
- and
- (d) oxidizing said sulfide to sulfate.
The process of claim 9 in which said oxygen-containing gas is air.
A process for purifying oil shale retort water having a substantial amount of organic content, said retort water having sufficient inorganic components, including sulfate, to enable the growth of anaerobic bacteria, comprising:
- (a) adding to said retort water bacteria of the Desulfovibrio family of bacteria capable of growth by utilizing said organic content;
- (b) producing in said retort water under anaerobic conditions a growth of cell biomass of said bacteria aggregated into a fluocculent mass, and reducing said sulfate to sulfide;
- and thereafter
- (c) removing said aggregated cell biomass from said retort water;
- (d) adding to said retort water after step (c) bacteria of the Thiobaccillus family of bacteria and aerating said retort water with oxygen-containing gas to oxidize said sulfide to sulfate;
- and
- ((e) recycling at least part of the sulfate from step (d) to said retort water prior to step (b) in an amount sufficient to neutralize said retort water to a pH in the range of about 6.7-7.5.
Dependencies are inferred from the claim text.