What is tertiary treatment of waste water?

Answer 1

Around 85% of TSS, BOD, and some portion of phosphorus, heavy metal, and nitrogen from the wastewater is removed by secondary treatment. The third stage known as the tertiary treatment of the wastewater can remove the loads of phosphorous and nitrogen which is present in the water. They comprise processes like ion exchange, filtration, and absorption of activated carbon, nitrification, electrodialysis, and denitrification. In tertiary treatment, the options of treatment depend on the characteristics of effluent after the second treatment and the kind of water which is needed at the very end of the treatment. Like in the case of potable water, disinfection and filtration are to be done upon the wastewater.

Filtration Process

The process of filtration can take out the particulate matter by passing the water via the porous media. The process of filtration comprises several types of media which are mainly sand, charcoal, and gravel. There are mainly two types of filtration of sand, which are slow and rapid sand filtration.

Membrane Process

For treating a varied range of wastes that includes organic and inorganic matter, sewage, and water-soluble oil wastes, membrane technology is used. On the basis of the separation mechanism and driving force like Ultrafiltration (UF), Multi Filtration (MF), Reverse Osmosis (RO), Nanofiltration (NF), and Forward Osmosis (FO), the membrane processes are classified.

Advanced Oxidation System

For destroying the microorganisms in the process and degrading the organic pollutant, ozone is introduced. By passing the oxygen via a high voltage electric field, Ozone gas (O3) is formed. Presently, ozone is used widely as a disinfectant after chlorine.

Answer 2

Secondary sewage treatment is when bacteria are used to break down the left over materials that have passed throught primary sewage treatment.

Answer 3

Tertiary treatment of waste water removes stubborn contaminants that were not removed during the secondary treatment.