Abstract: A chemical blend that simultaneously kills bacteria and suppresses the production of hydrogen sulfide (H2S) includes both a first chemical, which may be a glutaraldehyde, a tetrakishydroxymethyl phosphonium sulfate (THPS), a quaternary amine compound, a thiocyanate, a carbamate, a cinnamaldehyde, an alkyl dimethyl benzyl ammonium chloride, and/or a diamine diacetate; a second chemical which is a quinone; optionally a third chemical, which is a phosphate compound and a solvent which includes monoethylene glycol. The chemical blend has shown synergistic results for killing bacteria and/or suppressing the production of hydrogen sulfide as compared with the addition of the results of each of the components of the blend used separately.