INTRODUCTION TO OZONATION & OZONE
Ozonation is a chemical water treatment which involves onsite ozone generation for disinfection & degradation of organics, inorganic pollutants, color removal, BOD/ COD reduction from water and waste water.
Ozone is considered as a strong oxidant and virucide. Ozone is produced when Oxygen (O2) molecules are dissociated into ‘O’ atoms and eventually collide with other Oxygen molecules to form unstable gas, ozone (O3).
PRINCIPLE OF OZONE GENERATOR
Since, Ozone is very unstable and short lived; it is generated onsite using ozone generators. The Ozone generators works either on the principle of Coronary Discharge or UV light.
- Corona discharge:
The machines working on corona discharge principle take up oxygen and forces it to pass through a high voltage metallic grid to split the O2 molecule in O atom. These O atoms combine with O2 to form O3.
The method is efficient in generating high levels of O3 and fast removal of organics.
Corona Discharge is the most commonly used method for generation of Ozone.
- UV light:
The Sun’s UV radiation is used to split the Oxygen molecules to atoms. Subsequently, the atoms combine with molecular oxygen to form ozone. The above process occurs when the UV light hits the oxygen molecule at a wavelength of 254 nm.
Compared to Corona Discharge, this method produces low level of ozone and is less efficient.
TYPES OF OZONE GENERATING FEED GAS
- Ambient Air:
Air which is available naturally in the environment whether it is Indoor or Outdoor. Effective for machines producing low level of ozone.
- Dry Air:
Air which has moisture removed so the dew point is – 70 ℉ or lower. Effective for machines producing low levels of ozone.
- Concentrated Oxygen: Air which has 90% concentrated pure oxygen and moisture removed upto dew point of – 100 ℉.
The Ozone disinfects the water through oxidation destructing the cell wall of the microorganisms causing leakage of the cell constituents.
Through Oxidation by Ozone, the organic pollutant degrades to smaller components & less harmful components.