Question

Study the diagram given below and answer the question that follow:

1. Sewage is defined as:
   1. Municipal solid waste. 
   2. Municipal waste water. 
   3. Non-biodegradable waste. 
   4. Biodegradable plastic waste.
2. The primary treatment of waste involves:
   1. mechanical removal of grit. 
   2. chlorination 
   3. addition of microbes. 
   4. removal of harmful colours.
3. As a part of secondary treatment floes are added. What are these floes?
   1. Masses of specific chemicals to treat the waste. 
   2. Pieces of spongy material to absorb the waste. 
   3. Masses of bacteria associated with fungal filaments.
   4. Biodegradable masses trapped in mesh-like structures.
4. What is the effect of the process of sewage treatment on the value of the BOD?
   1. Increases
   2. Decreases
   3. Remains unaffected
   4. becomes unstable
5. A major part of the studge is pumped into large sludge digester tanks where a mixture of gases is produced. The main component of this gaseous mixture is:
   1. Carbon dioxide 
   2. Hydrogen 
   3. Hydrogen sulphide 
   4. Methane

Answer 1

1. Municipal waste water.
2. Mechanical removal of grit.
3. Masses of bacteria associated with fungal filaments.
4. Decreases
5. Methane