A treatment process for remediating contaminants in a mixture of contaminated fluids, including at least one liquid fluid and at least one gaseous fluid, includes the steps of: preparing a liquid treatment composition containing at least 80 volume % of an aqueous solution containing at least one hydroxide compound at a collective concentration of 35-55 weight percent, and at least one of fulvic acid and humic acid at a collective concentration of 0.1-5 wt % of the treatment composition; adding a dosage of the treatment composition to a mixture of contaminated fluids including a liquid portion and a gaseous portion; and allowing the treatment composition to react with the mixture of contaminated fluids for at least 10 minutes, wherein a pH of the treatment composition is at least 13.0 and the aqueous solution contains at least one of NaOH and KOH.