The domestic sewage in large cities:
The domestic sewage in large cities:
The correct option is B Is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)
The correct option is B:
Explanation of the correct option:
- Sewage treatment refers to the process in which contaminants are removed from wastewater and household sewage.
- It includes all three processes, which are physical, chemical, and biological.
- It ultimately produces fluid waste that is environmentally safe and the solid waste can be disposed of easily.
- It involves three stages:
- Primary treatment:
- This process involves removing the materials that can be collected physically.
- In this process, the tree limbs, leaves, trash, plastics, etc. are physically removed.
- The materials that are settled and also the floating ones are removed.
- Secondary treatment:
- In this process, the dissolved and suspended biological matter is removed.
- It entails removing microorganisms before sending them to tertiary treatment.
- Tertiary treatment:
- It is the final treatment stage. After this, the water is discharged into the receiving environment, which can be a river, lake, or sea.
- This is also called effluent polishing.
Explanation of the incorrect options:
Option A:
Domestic sewage never has very large particles; it only contains the cut slices of fruits, vegetables, and other biodegradable waste.
Option C:
Domestic sewage does not have a high biological oxygen demand (BOD) and it only depends upon the presence of aerobic bacteria.
Option D:
When treated in STPs it still requires the aeration step as the sewage does not contains adequate oxygen.
Final answer: The domestic sewage in large cities is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs).
Is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)
The correct option is B:
Explanation of the correct option:
- Sewage treatment refers to the process in which contaminants are removed from wastewater and household sewage.
- It includes all three processes, which are physical, chemical, and biological.
- It ultimately produces fluid waste that is environmentally safe and the solid waste can be disposed of easily.
- It involves three stages:
- Primary treatment:
- This process involves removing the materials that can be collected physically.
- In this process, the tree limbs, leaves, trash, plastics, etc. are physically removed.
- The materials that are settled and also the floating ones are removed.
- Secondary treatment:
- In this process, the dissolved and suspended biological matter is removed.
- It entails removing microorganisms before sending them to tertiary treatment.
- Tertiary treatment:
- It is the final treatment stage. After this, the water is discharged into the receiving environment, which can be a river, lake, or sea.
- This is also called effluent polishing.
- Primary treatment:
Explanation of the incorrect options:
Option A:
Domestic sewage never has very large particles; it only contains the cut slices of fruits, vegetables, and other biodegradable waste.
Option C:
Domestic sewage does not have a high biological oxygen demand (BOD) and it only depends upon the presence of aerobic bacteria.
Option D:
When treated in STPs it still requires the aeration step as the sewage does not contains adequate oxygen.
Final answer: The domestic sewage in large cities is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs).
