Abstract: Synergies in recovery of reverse osmosis (RO) membrane process reject waste and forward osmosis (FO) membrane process water extraction, using such osmotic process byproducts in applications for makeup to evaporative cooling towers, concurrent with use of specific corrosion and scale inhibition methods that permit tower water discharge reduction to approach zero blowdown. Such synergies are derived from methods for application of subsequent RO feed water and reject wastewater with pre-treatment steps, and FO process optimization steps to permit water quality and economic performance efficiencies when used as makeup to evaporative cooling systems.

Abstract: Synergies in recovery of reverse osmosis (RO) membrane process reject waste and forward osmosis (FO) membrane process water extraction, using such osmotic process byproducts in applications for makeup to evaporative cooling towers, concurrent with use of specific corrosion and scale inhibition methods that permit tower water discharge reduction to approach zero blowdown. Such synergies are derived from methods for application of subsequent RO feed water and reject wastewater with pre-treatment steps, and FO process optimization steps to permit water quality and economic performance efficiencies when used as makeup to evaporative cooling systems.

Abstract: Methods for inhibiting corrosion in aqueous evaporative systems where soluble silica (SiO2) is maintained at residuals between 10 Mg/L and saturation, but more preferably maintained at greater than 300 mg/L as SiO2, to provide corrosion inhibiting silica films that protect system metals. Silica is provided by evaporation of water and subsequent concentration and transformation of silica naturally contained in source water. The methods of the present invention provide highly effective inhibition of corrosion for mild steel, copper, stainless steel, aluminum, zinc, galvanized steel and various alloys of such metals. The methods of the present invention comprise pretreatment removal of polyvalent metal ions from the makeup source water, maintenance of concentration of monovalent metal ions, and controlling pH at a minimum of 7.0 in the presence of an elevated temperature aqueous environment.

Abstract: A method of providing corrosion inhibition to copper, nickel, aluminum, zinc, tin, lead, beryllium, carbon steel, various alloys of such metals, and galvanized coatings in evaporative cooling water applications approaching zero liquid discharge that are specifically attacked by cooling water with residuals of corrosive chemistry or ions such as ammonia/ammonium ion, chloride, high TDS, OH?, or high pH. The method includes applying azoles inhibitors (such as TTA, BTA, etc.) at residuals of 0.25 mg/L to 200 mg/L or greater (as azoles) to the cooling water application and operating with a combination of high TDS (greater than 2500 mg/L) and high pH (greater than 9.0), while maintaining low total hardness (less than 200 mg/L as CaCO3).