*2.5.3. Process*

*2.4.1. Advantages*

residual disinfectant.

10 Photocatalysts - Applications and Attributes

*2.4.2. Chloramination equipment*

potentially explosive compound [11].

• Ozone possesses strong oxidizing power

• Oxygen is provided to water after disinfection

• Reacts with and removes all organic matter [13].

• No change in color and taste occurs.

• Requires no chemicals

*2.5.2. Limitation*

• Destroys and removes algae • Oxidizes iron and manganese

**2.5. Ozonation**

*2.5.1. Advantages*

• No by-products are formed in chloramination.

influence chloramine's future use [7].

• Chloramine is more stable but not a strong disinfectant as chlorine, providing long lasting

• However, the environmental protection agency (EPA) is eager to know about the type and quantity of disinfection byproducts produced by the interactions of chloramines, bromide, brominated organics, and by the chloramination of ozonized waters. EPA's findings may

Equipment for both the production of chloramines and chlorination systems are same. Both chlorine and ammonia might be introduced as a liquid or gas. Additionally, both chlorine and ammonia are available in liquid or granular form. Great care must be taken so that concentrated chlorine and ammonia are never mixed as they will form nitrogen trichloride, a

Ozone is an allotropic (unstable) formula of oxygen in which three molecules are combined to produce a new molecule. It quickly decomposes to generate highly reactive free radicals. The ozone's oxidation potential (−2.7 V) is greater than that of the chlorine (−1.36 V) or hypochlorite ion (−1.49 V), substances widely used in wastewater treatment such as oxidants. Ozone is surpassed only by the hydroxyl radical (•OH) and fluoride in its oxidation capacity [7, 12].

• Short reaction time is needed so germs (including viruses) are killed in a few seconds

Onsite generation is necessary as ozone is unstable at atmospheric pressure. It is toxic in high concentrations as it is a greenhouse gas. The three modules of an ozone plant are ozone

Following are the advantages when ozone is used to treat water:

Ozone is produced from a gas containing oxygen (usually ambient air or pure oxygen). The gas is then passed through an electric field. The air is treated to make sure that it is dry and free from dust impurities. Oxygen is converted to ozone in an electrical field. The ozone is then fed to the contact tank so that ozone is dissolved by water to proceed disinfection process [14].
