Ozone Water Purification
Ozone is essentially a gas derivative of Oxygen, when dry and subjected to a high voltage, the normal Oxygen atom (O2) splits and creates an unstable molecule called Ozone (O3) and has a high potential of oxidation as well as extremely effective as a disinfectant.
Ozone is widely used in water purification where it assists in oxidizing dissolved iron, manganese, and sulfur that may be present in the water to form insoluble metal oxides or elemental sulfur. In addition, organic matter is destroyed, where these particles are then removed by post-filtration.
Ozone is generated at the point of use and because it is unstable will quickly adopt a free molecule returning it back to elemental oxygen in a short amount of time after generation, it therefore has no residual, and will dissipate, Ozone cannot be utilized for long term bulk storage disinfection protection.
ADVANTAGES AND DISADVANTAGES
- Ozone is more effective than chlorine in destroying viruses and bacteria.
- The ozonation process utilizes a short contact time (approximately 10 to 30 minutes).
- There are no harmful residuals that need to be removed after ozonation because ozone dissipates rapidly.
- After ozonation, there is no regrowth of microorganisms, except for those protected by the particulates in the wastewater stream.
- Ozone is generated onsite, and thus, there are fewer safety problems associated with shipping and handling.
- Ozonation elevates the dissolved oxygen (DO) concentration of the effluent. The increase in DO can eliminate the need for re-aeration and may also raise the level of DO in the receiving stream.
- Low dosage may not effectively inactivate some viruses, spores, and cysts.
- Ozone is very reactive and corrosive, thus requiring corrosion-resistant material such as stainless steel, polyprop or Teflon.
- Ozonation is not economical for wastewater with high levels of biochemical oxygen demand (BOD), chemical oxygen demand, or total organic carbon.
- Ozone can be toxic if inhaled in large doses.
Ozone disinfection can be used on most water plants particularly as primary disinfection especially when reverse osmosis is incorporated. In addition to disinfection, another common use for ozone in wastewater treatment is odor control.