Question

Describe the processes carried out at a wastewater treatment plant

Answer 1

There are three stages of treating the wastewater:
Primary Treatment: sewage is carried sewers to a sewage treatment plant. Here ,the large solids ,like leaves,rags and plastic , are first separated by strainers or screens. After this,the sewage is passed through a grit and sand removal tank called grit chamber. then the sewage is passed through settlement tanks,where most of the suspended solids sink to the bottom. The solids that settle at the bottom of settlement tanks are referred to as primary sludge . This sludge can be used to produce compost and biogas . floating solids are removed with the skimmer . The water that comes out of the settlement tanks is called clarified water.




Secondary Treatment: This involves the breaking down of organic matter by the action of bacteria. This can be done in open tanks called aeration tanks. Aerobic bacteria that need oxygen , act on the clarified water in these tanks. Often air is blown into these tanks. Sometimes , anaerobic bacteria are used to break down the organic matter dissolve in sewage . The process takes place in closed tanks. In either case , the action of bacteria makes solids settle down at the bottom. This is called biological or secondary sludge.


Tertiary treatment: Sometimes the wastewater is treated further before being discharged into water bodies . It may be passed through sand filters,or man-made pond containing reeds and certain organisms that clean out some dissolved chemicals. Water hyacinth , for example , is considered as an excellent natural cleanser . Water can also be chemically treated by addition of chlorine or exposure to ultraviolet rays to kill remaining bacteria.

Hope this helps.

Answer 2

Explanation:

describe the process carried out at a waste water treatment plants