Produced water is the water that comes out as a byproduct during oil and gas exploration. The water is trapped below the layer of hydrocarbons and contains various hydrocarbons in the form of oil. Along with oil and hydrocarbons, the produced water may also contain waxes, greases, sand, scales, dissolved salts, CO2 (carbon dioxide), and H2S (hydrogen sulfide) gas, production chemicals, and various metals, such as zinc, lead, manganese, iron, and barium. The process water is treated and reused for irrigation or industrial process water.