Chemical solution and methods of using same for remediating hydrogen sulfide and other contaminants in petroleum based and other liquids

A treatment process for preparing a remediated liquid from a contaminated liquid originally containing more than 5 ppm hydrogen sulfide (H2S), comprising steps of:

• preparing a stand-alone aqueous treatment solution consisting of water, at least one hydroxide compound and an antibacterial agent, in which a collective concentration of the at least one hydroxide compound in the aqueous treatment solution is in a range of 35-55 weight percent and collectively the at least one hydroxide compound and the water constitute at least 95 weight percent of the aqueous treatment solution;
• adding to the contaminated liquid an amount of the aqueous treatment solution sufficient to reduce a concentration of hydrogen sulfide in the contaminated liquid to ≤5 ppm based on stoichiometry of reactions between the at least one hydroxide compound and the hydrogen sulfide in the contaminated liquid;
• and
• dispersing the aqueous treatment solution in the contaminated liquid and allowing the aqueous treatment solution 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 due to the reactions between the at least one hydroxide compound and the hydrogen sulfide in the contaminated liquid.