NPTEL Introduction to Environmental Engineering and Science-ASS5

Which one is the correct formula for BOD5 of wastewater?

• 𝐵𝑂𝐷5 = (𝐷𝑂𝑖 − 𝐷𝑂𝑓)/p

• 𝐵𝑂𝐷5 = (𝐷𝑂𝑓 − 𝐷𝑂𝑖)/p

• 𝐵𝑂𝐷5 = (𝐷𝑂𝑖 − 𝐷𝑂𝑓)p

• 𝐵𝑂𝐷5 = (𝐷𝑂𝑓 − 𝐷𝑂𝑖)p

Match the followings:

1.Use of biogas i) Reduction in atmospheric release of landfill gas

2. Benefit of anaerobic digestion ii) Amino acid

3. Conversion of CO2, H2 to CH4 iii) Transport fuel

4. Building block of protein iv) Methanogenesis

• 1(i), 2(iii), 3(ii), 4(iv)

• 1(iii), 2(i), 3(iv), 4(ii)

• 1(iv), 2(ii), 3(iii), 4(i)

• 1(ii), 2(i), 3(iv), 4(iii)

Which of the following options is/are correct related to the microbial fuel cell (MFC)?

• MFC stands for methanogenic fuel cell

• MFC involves low sludge yield

• MFC has a low carbon footprint

• MFC needs a continuous air supply

Which of the following statements is/are correct related to the Nitrogen cycle?

• Nitrification is the process of converting ammonium to nitrate

• Nitrifying bacteria helps in converting Nitrogen into ammonium

• Nitrogen assimilation is the process of formation of organic nitrogen compounds from inorganic nitrogen compounds in the environment

• Denitrifying bacteria convert nitrite into nitrate

Eutrophication can be avoided by which of the following process?

• reducing the use of phosphates as builders in detergents

• adding phosphate-rich plant materials from affected lakes

• aerating lakes by external sources

• removing phosphate-rich sediments by dredging

Which of the following statements is/are correct concerning the BOD?

• BOD of water depends on temperature

• BOD applies to any material

• BOD of a sample varies with time

• High BOD in water leads to high oxygen availability to aquatic animals

Which of the following statements is/are correct corresponding to the composting process?

• Composting is an anaerobic process

• Composting is the adsorption of organic matter onto microorganisms

• Composting depends on temperature

• Compost contains nutrients for plant growth

What is the correct abbreviation of BOD?

• Biological oxygen demand

• Biochemical oxygen demand

• Bio-geochemical oxygen demand

• None

Which of the following is the correct sequence of waste degradation mechanisms in anaerobic digestion?

• Hydrolysis – acidogenesis – acetogenesis – methanogenesis

• Acidogenesis – acetogenesis – hydrolysis - methanogenesis

• Hydrolysis – acetogenesis – acidogenesis - methanogenesis

• Hydrolysis – methanogenesis – acetogenesis – acidogenesis

What pathways facilitate the transfer of pollutants from the environment to the human body?

• Inhalation

• Ingestion

• Absorption

• All of the above