Oxygen (O2) - constitutes approximately 21% of the air we breathe, has a gaseous specific gravity of 1.105 makes it slightly heavier than air, and has a boiling point of –297.3°F (-183°C), it becomes a transparent, pale blue liquid that is slightly heavier than water. Oxygen also colorless, odorless and tasteless & has poor solubility in water. The principal uses of oxygen are indicative of its strong oxidizing and life-sustaining properties. It’s used in medicine for therapeutic purposes and used in treatment of patients with respiratory disorders. In the chemical and petroleum industries, o xygen can be used as a chemical reactant and in combustion systems to have increased reaction rates, yield improvements, reduced capital cost of new plants and reduced air emissions. Furthermore, in acid sulfuric mill, oxygen use to alter the structure of feedstocks through oxidation, producing nitric acid, ethylene oxide, propylene oxide, vinyl chloride monomer and other building block chemicals. Oxygen is used in the pulp and paper industry for a variety of applications, including pulp bleaching, black liquor oxidation and lime kiln enrichment. Oxygen is frequently employed in iron, copper and lead blast furnaces, iron melting foundry cupolas and rock or slag-melting cupolas to increase productivity by increasing combustion temperatures and reduce the specific coke consumption. In metal cutting application, is use to support oxyfuel cutting operations. Oxygenfuel combustion is used in the glass industry to reduce particulate and Nitrogen Oxide (NOx) emissions in melting operations. In waste waterwater treatment, oxygen can be used in place of air in the activated sludge process to maintain a higher population of micro-organisms. Using oxygen injected through a side stream instead of using a mechanical aerator eliminates surface agitation, reducing odour. Injecting oxygen into pumped sewer mains maintains the sewage in an aerobic state, preventing formation of hydrogen sulphide.