Objective Question and Answer of Sanitation Engineering

  1. What is Split Chlorination?

Ans- Addition of chlorine to the sewage, both at the begining and at the end of treatment process , is known as split chlorination.

  1. Differentiate between pre chlorination and post chlorination.

Ans- When chlorine is added to the treated sewage as a final step in its treatments, is called post chlorination whereas pre-chlorination of the sewage is done before it enters the sedimentation tank.

  1. What is Clarigester?

Ans- It is an Imhoff type double storey tank without a bottom hopper and duly filled with mechanical sludge and screen breaking equipment, is called a clarigester.

  1. Define the percolation rate of soil?

Ans- The time in minutes required for the seepage of water through the soil by 1 cm is called the percolation rate of soil.

  1. What is the principle of the sludge digestion septic tank?

Ans- The septic tanks works on the principle of digestion of the settled sludge by anaerobic decomposition process.

  1. What is septic Tank?

Ans- A septic tank may be defined as a primary horizontal continuous flow type sedimentation tank with a longer detention period and with a provision for the settled sludge.

  1. What is algal photo synthesis?

Ans- The combined action of algae and other microorganisms, to produce oxygen, is known as algal photosynthesis or algal symbious.

  1. What is oxidation pond?

Ans- An open flow through earthen-basin designed and constructed to treat the sewage and biodegradable industrial waste water , is called oxidation pond.

  1. What is sludge volume index?

Ans- The degree of concentration of the sludge produced in the biological aeration in the activated sludge plant, is known as sludge volume index.

  1. Differentiate between the mixed liquor suspended solids and mixed liquor volatile suspended solids.

Ans- The suspended solids in the sewage is called the mixed liquor suspended solids whereas the mixed liquor volatile suspended solids contain only the mixed liquor volatile suspended solids.

  1. What is sludge age?

Ans- The average time for which particles of suspended solids remain under aeration, is known as the sludge age. It indicates the residence time of biological solids in the system.

  1. Why does the rising sludge phenomenon take place in secondary clarifers of an activated sludge plant?

Ans- Denitrification of nitrates into free nitrogen results in the formation of nitrogen bubbles which lift up the settled sludge and cause the phenomenon of rising sludge.

  1. What is bulking sludge?

Ans- The sludge that exhibits poor settling characteristics is called bulking sludge.It is caused by filamentous micro-organisms.

  1. What is sludge lagoon?

Ans- A large shallow open land is used to keep raw sludge at rest for a detention period of  1 to 2 months, is called sludge lagoon.

  1. What percentage of useful chemicals are found in sludge?

Ans- 1.% of nitrogen of phosphoric acid and 0.5% of potash are useful chemicals that are found in the dry sludge.

  1. How much time require to drying the sludge?

Ans- It takes about 2 weeks to 2 months for drying the sludge depending on the climatic conditions of the area.

  1. What are the factors that affect the capacity of digestion tank?

Ans- The following factors affect the capacity of a digestion tank,

  1. Sludge tank
  2. Digestion period
  3. Degree of digestion
  4. Loss of moisture
  5. Conversion of organic matter

18. What is activated sludge plant?

Ans- An activated sludge plant consists of aeration tank,witha feed of active sludge along with a secondary settling tank.

  1. What are anaerobic biological units?

Ans- The treatment reactors in which organic matter is decomposed and stabilised by anaerobic bacteria, are known as anaerobic biological units.

  1. What is lagoon?

Ans-  A large shallow open pond which is used to keep raw sludge at rest for a detention period of 1 to 2 month, is called lagoon.

  1. What are acid former?

Ans- Anaerobic and facultative bacteria which solubilise the organic solids through hydrolysis and thereafter the soluble products are fremented to volatile acids and organic alcohols of low molecular weight, are called acid former.

  1. What is detritus tank?

Ans- The grit chamber design to flow with a smaller flow velocity about 0.9 m/sec  and a longer detention period so that larger grit as well as very fine sand particles get seperated, is technically known as detritus tank.

  1. What is incineration?

Ans- The process of burning of the screening is called incineration.

  1. What is meant by primary treatment of sewage?

Ans- The treatment of the sewage by which large suspended organic solids are removed by sedimentation in a settling basin, is known as primary treatment of sewage.

  1. What is sewage sickness of land?

Ans- The land where soil pores or voids get filled and clogged with sewage matter and free circulation gets prevented and also anaerobic conditions develop, is said to be suffering from the sewage sickness.

  1. What is thermocline?

Ans- The intermediate zone between epilimnion zone that contains warmer, well mixed aerobic depth of water and the hypolimuion zone that contains cooler, poorly mixed and anaerobic water, is called thermocline.

  1. What is limnology?

Ans- The study of physical phenomena of lakes and other fresh water bodies, is called limnology.

  1. Name the nutrient largely contained industrial and domestic waste water.

Ans- Phosphorous.