Consider the following tertiary treatment methods for treatment of waste water: 1. Ion-exchange method 2. Reverse osmosis 3. Chemical oxidation method 4. Activated sludge process Which of the above methods are correct ?

Consider the following tertiary treatment methods for treatment of waste water: 1. Ion-exchange method 2. Reverse osmosis 3. Chemical oxidation method 4. Activated sludge process Which of the above methods are correct ? Correct Answer 1, 2 and 3

There are three distinct steps involved in traditional wastewater treatment methods.

Primary wastewater treatment:

• Primary treatment of wastewater involves sedimentation of solid waste within the water. This is done after filtering out larger contaminants within the water.
• Wastewater is passed through several tanks and filters that separate water from contaminants.
• The resulting sludge is then fed into a digester, in which further processing takes place.
• This primary batch of sludge contains nearly 50% of suspended solids within wastewater.

Secondary wastewater treatment:

Secondary treatment of wastewater makes use of oxidation to further purify wastewater. This can be done in one of three ways:

• Biofiltration
• Aeration
• Oxidation ponds

Tertiary wastewater treatment:

• It is mostly comprised of removing phosphates and nitrates from the water supply.
• Substances like activates carbon and sand are among the most commonly used materials that assist in this process.
• Several methods have been applied for final treatment, such as adsorption using activated carbon or other appropriate sorbents, post precipitation, ion-exchange, reverse osmosis, electrochemical treatment, and evaporation.