Chemical compositions and methods for remediating hydrogen sulfide and other contaminants in hydrocarbon based liquids and aqueous solutions without the formation of precipitates or scale

A treatment process for preparing a remediated liquid from a contaminated liquid originally containing more than 5 ppm hydrogen sulfide (H2S) and substantially without formation of precipitate, comprising steps of:

• preparing an aqueous solution containing at least one hydroxide compound, in which a collective concentration of the at least one hydroxide compound in the aqueous solution is in a range of 35-55 weight % and a content of water is at least 30 weight %;
• adding the aqueous solution to the contaminated liquid at a dosage amount which provides a concentration of the at least one hydroxide compound within a range of 125-5000 ppm of in the contaminated liquid;
• adding at least one organic acid selected from a group consisting of a fulvic acid and a humic acid to the contaminated liquid at a dosage amount which provides a concentration of the at least one organic acid of at least 0.01 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.