The sustainable development of the world civilization requires a proper waste handling and management. Mercury is one of the most hazardous water pollutants. Additionally, hydrogen sulfide is a life-threatening natural gas contaminant. In this work, a one-pot process for the concurrent removal of mercury (Hg(II)) from mercury-polluted wastewaters and hydrogen sulfide (H2S) scavenging from sour natural gas has been developed. In this process, the sour natural gas is fed into a bubble column reactor filled with synthetic wastewater containing different levels of Hg(II). The contact of H2S in the inlet gas with the dissolved Hg(II) in the wastewater samples promotes the reaction of H2S with Hg(II), forming a water-insoluble HgS precipitant. This leads to the purification of both, the water sample and the gas stream without the need for adding any external material. Almost a complete Hg(II) removal (≥97.6%) from the synthetic wastewater samples is attainable irrespective of the initial Hg(II) concentration. Additionally, each kilogram of Hg(II) could scavenge up to 147.3 and 169.3 g H2S from the entering sour natural gas at the breakthrough and the saturation time, respectively. These findings reveal the efficacy of the proposed process for the simultaneous removal of Hg(II) from mercury-contaminated waters and H2S from sour gases using a single unit operation. Thus, the proposed process herein is novel and very appealing from economic, operational, environmental, and safety/occupational health perspectives. Display omitted •A bubble column reactor has been used to concurrently remove Hg(II) and H2S.•≥ 97.6% Hg(II) removal from wastewater can be obtained.•About 170 g/kg H2S scavenging capacity might be obtained.•Hg(II) removal and H2S scavenging capacity are independent of Hg(II) initial concentration.•The proposed process has multiple economic, environmental, and societal benefits.