Process for removal of dissolved hydrogen sulfide and reduction of sewage BOD in sewer or other waste systems

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. nitrate oxygen per lb. of sulfide is required.

Description

BACKGROUND AND SUMMARY OF THE INVENTIONThis invention relates to a process for the removal or reduction of dissolved hydrogen sulfide, and reduction of BOD in sewer systems, municipal waste treatment plants and in other industrial waste applications.It is known to add nitrates or nitrites to sewage to effect reduction in BOD and even to suppress the formation of hydrogen sulfide gas via bacterial action. See, for example, U.S. Pat. Nos. 3,300,404; 4,446,031; and 4,681,687.It is also known to add nitrates to sewage in order to control objectionable odors. See, for example, U.S. Pat. Nos. 3,966,450; 4,108,771.There have also been attempts to remove hydrogen sulfide directly from waste. For example, in U.S. Pat. No. 4,680,127, the patentee adds amounts of glyoxal, or glyoxal in combination with formaldehyde or glutaraldehyde, in order to reduce or scavenge the amount of hydrogen sulfide in aqueous or wet gaseous mediums.In U.S. Pat. No. 4,501,668, the patentee utilizes polycondensation...

AI Technical Summary

Benefits of technology

It has now been discovered that the addition of nitrate, via an aqueous sodium nitrate solution, to sewage systems, waste treatment plants and other industrial waste applications containing dissolved hydrogen sulfide will result in the elimination or substantial reduction of the hydrogen sulfide, as well as the elimination of other "minor" odors associated with other sulphur-containing compounds.

Problems solved by technology

Moreover, the removal of hydrogen sulfide is not instantaneous.

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