16. Answer in detail V

 

a. Water recyclingRainwater harvesting is reusing the treated wastewater for beneficial purposes like agriculture and irrigation, industrial processes, potable water supplies, flushing in toilets, environmental restoration and groundwater recharge.

 

b. The sources of water that can be recycled includes all of the aboveindustry process and cooling wateragricultural runoffmunicipal wastewater.

 

c. Wastewater treatment consists of fourthreefive main stages. In some of the applications, a more advanced treatment called quarternarysecondarytertiary treatment is required.

 

d. During tertiarysecondary primary treatment, wastewater is held temporarily in a settling tank. In the tank, the lighterheavier solids settle at the bottom of the tank, while heavierlighter solids like oil and grease floats over the surface.

 

e. TertiaryPrimarySecondary  treatment is the second phase of wastewater treatment, used to remove the biodegradable dissolved organic matter. It is performed in the presence of oxygen through the process of biological oxidation by aerobicanaerobic microorganisms.

 

f. The tertiaryprimarysecondary treatment is also called the advanced treatment. It is the final step of sewage treatment. The treatment aims to raise water quality to the industrial and domestic standards or meet specific requirements.