Abstract: A treatment method for reducing or preventing the production of sulfide compounds of hydrogen such as H2S dissolved in aqueous effluent constituents of waste water passing through a conduit of a sewerage system upstream of a plant for the biological treatment of water, the conduit containing sulfate-reducing bacteria and organic or mineral sulfur-containing compounds, wherein an alkaline-earth or alkali metal nitrite is injected into the effluent entering the conduit, the effluent and/or the bacterial biofilm covering the inner wall of the conduit containing or being supplemented, if necessary, by a combination of aerobic bacteria and anaerobic bacteria other than SRB bacteria, the concentration of nitrite injected into the effluent entering the conduit under full load being 0.036 mole/m3 to 0.087 mole/m3 to reduce the concentration of H2S dissolved in the effluent at the outlet from said conduit that would be produced in the absence of nitrite by 1 g/m3.