Process for removal of dissolved hydrogen sulfide and reduction of sewage BOD in sewer or other waste systems
AssigneeDavis Water & Waste Industries, Inc.
InventorsDavid J. Hunniford, H. Forbes Davis
Life of this patent
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Abstract
Removal of dissolved hydrogen sulfide and a reduction in BOD is achieved by the addition of nitrate ions to waste systems in an amount sufficient to stimulate growth of bacteria which utilize dissolved hydrogen sulfide in their metabolism. Specifically, about 2.4 lbs. oxygen per lb. of sulfide is required.
Claims28
A process for removing dissolved hydrogen sulfide from waste systems comprising the steps of:
- (a) adding nitrate ions to the waste in accordance with a ratio of at least 2.4 parts nitrate oxygen for each 1 part dissolved sulfide in order to provide a source of oxygen for naturally occurring bacteria present in the waste which utilize dissolved hydrogen sulfide in their metabolism;
- (b) providing sufficient time to culture said bacteria within said waste systems;
- and
- (c) providing ongoing time sufficient to enable said bacteria to remove the dissolved hydrogen sulfide.
A process for removing from waste systems dissolved hydrogen sulfide and other minor odors associated with other sulphur-containing compounds comprising the steps of:
- providing a source of oxygen in the form of nitrate in the form of nitrate in the waste in sufficient amount to cause naturally occurring bacteria in the waste which utilize dissolved hydrogen sulfide and sulfur in their metabolism to grow, and providing sufficient time for the bacteria to culture in said waste, to thereby initiate a biochemical reaction which has the following half reactions:
- 8 NO.sub.3 -.fwdarw.4N.sub.2 +120.sub.2
- 120.sub.2 +5H.sub.2 S.fwdarw.5SO.sub.4.sup.2- +4H.sub.2 O+2H.sup.+
A process for removing dissolved H.sub.2 S and reducing sewage BOD in sewer systems comprising the steps of:
- (a) adding a source of oxygen in the form of nitrate to the sewer system in an amount equal to about 2.4 lb. oxygen per lb. sulfide;
- and
- (b) providing about 8 to about 96 hours to allow naturally occurring bacteria already present in the system to culture as a result of the addition of said source of oxygen;
- and providing about 1.5 to about 20 hours to effect ongoing H.sub.2 S removal and sewage BOD reduction.
Dependencies are inferred from the claim text.