Environmentally friendly processes for killing pathogens in water involves adding to the water an amount sufficient of a hydrogen peroxide solution having a pH of less than 4, to kill pathogens in the water, wherein the hydrogen peroxide solution contains metallic ions of silver and at least one of copper and zinc, metallic ions being present in the hydrogen peroxide solution in an amount of 10 ppb to 5%; wherein the hydrogen peroxide solution contains at least one of peracetic, nitric, sulfuric and phosphoric acids; wherein the solution preferably contains one or more of sulfuric acid, salicylic acid, phosphonic acid, citric acid and glycerin; and wherein the water is preferably also subjected to UV and/or IR radiation.