Patent ID: 6309597
Filing Date: 2001-10-30
Classification: A01N,C02F,E21B

Abstract:
A method for reducing the level of hydrogen sulfide (H.sub.2 S) in water of pH 4-10, having dispersed therein indigenous amounts of sulfate-reducing bacteria and H.sub.2 S-metabolizing bacteria, comprising adding to the H.sub.2 S-containing water:(a) finely divided particles of polycyclic quinone selected from anthraquinone, anthrahydroquinone and mixtures thereof, the average size of the particles being no greater than 10 micrometers, which particles are applied as an aqueous dispersion of (a) water-insoluble non-ionic particles suspended in an aqueous medium or (b) an alkaline solution of an ionic salt of the polycyclic quinone having a pH at least 2 pH units higher than the H.sub.2 S-containing water, which salt is thereby converted to the corresponding water-insoluble, non-ionic polycylic quinone particles upon exposure to the lower pH of the H.sub.2 S-containing water and(b) an aqueous solution of metallic nitrogen oxide selected from the group consisting of metal nitrate, nitrite and mixtures thereof, the weight ratio of polycyclic quinone to metallic nitrogen oxide being (3-30).times.10.sup.-3, and the amount of the polycyclic quinone and nitrogen oxide added to the H.sub.2 S-containing water being sufficient to increase its oxidation-reduction potential (ORP) to a preselected higher level.