A treatment process for remediating a contaminated liquid containing more than 5 ppm hydrogen sulfide and substantially without formation of precipitate, includes steps of steps of adding an aqueous solution containing at least one hydroxide compound at a collective concentration of 35 – 55 wt% to the contaminated liquid to achieve a concentration of 125-5000 ppm of the hydroxide compounds in the contaminated liquid, adding at least one organic acid and to the liquid to achieve a concentration of 0.01 – 10 ppm in the contaminated liquid, and dispersing the aqueous solution and the at least one organic acid in the contaminated liquid and allowing the aqueous solution and the at least one organic acid to react with the contaminated liquid for a period of time until a concentration of hydrogen sulfide in the contaminated liquid is reduced to ≤ 5 ppm.