Environmental Studies · General Awareness

Water Quality and Pollution

1,303 Questions

Water Quality and Pollution examines the sources, mechanisms, and impacts of contaminants in aquatic ecosystems. It covers crucial environmental concepts like eutrophication, biochemical oxygen demand, and thermal pollution. This subject frequently appears in general science and environmental studies sections of various examinations.

Eutrophication CausesThermal Pollution EffectsBiochemical Oxygen DemandSynthetic Fertilizer ImpactsWastewater SourcesAquatic Ecosystem Toxicity

Water Quality and Pollution Questions

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Measurement of the rate of oxygen utilization by a unit volume of water over a period of time is to measure

  1. Biochemical oxygen demand

  2. Biosynthetic pathway

  3. Biogas generation

  4. Fermentation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Biochemical Oxygen Demand (BOD)is defined as the amount of dissolved oxygen needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
  • BOD is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have on the receiving environment. The higher the BOD value, the greater the amount of organic matter or “food” available for oxygen-consuming bacteria.
  • Hence Measurement of the rate of oxygen utilization by a unit volume of water over a period of time is to measure Biochemical oxygen demand.
  • So, the correct answer is 'Biochemical oxygen demand'.
Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Water pollution can be decreased by proper collection and disposal of domestic sewage.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Proper disposal of the domestic waste before it goes in to the lakes and oceans is useful in preventing water pollution. Domestic sewage which is the waste water that goes out into the environment through several routes should be treated before being released. It contains soaps, detergents, toilet paper, household refuse all of which causes water pollution. All this sewage should be properly collected and treated in which contaminants are removed from sewage to produce sludge suitable for discharge into the environment. 

Thus, the correct answer is option A. 

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Sewage water can be purified by 

  1. Aquatic plant

  2. Microorganism

  3. Penicillin

  4. Fishes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Domestic sewage primarily contains biodegradable organic matter, which readily decomposes by bacteria and other micro-organisms, which can multiply using these organic substances as substrates and hence utilise some of the components of sewage. It is possible to estimate the amount of biodegradable organic matter in sewage water by measuring biochemical oxygen demand (BOD). It can be purified treating with with micro-organisms.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Sewage water can be purified for recycling with the action of

  1. Microorganisms

  2. Aquatic plants

  3. Fishes

  4. Penicillin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The sewage water can be treated in the treatment plants with the use of microbes. The bacterial cells, fungal cells and algae are the common microbes which are used for the cleaning of the waste. The microbes have the ability to feed and decompose on the organic matter and convert it to simpler non-toxic forms. The organic matter of the wastewater can be reduced and the water can be purified. 

Thus, the correct answer is option A. 

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Polluted water can be purified by using

  1. Microorganisms

  2. Algae

  3. Pesticides

  4. Fishes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The polluted water can be purified using the treatment plants. Activated sludge method refers to floc of microorganisms like bacteria and fungi which are used in the process to break down organic matter into carbon dioxide, water, and other inorganic compounds. There are microbes which grow in the water forming mass or flocs and help in the clearing of the water. These flocs are used in the next round of treatment plants for efficient removal of wastes.

Thus, the correct answer is option A. 

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

When harmful substances get mixed with water it becomes

  1. polluted

  2. muddy

  3. pure

  4. unclean
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Water pollution is defined as the contamination of water bodies by harmful substances, which makes the water unsafe or unsuitable for its intended use.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Sewage water carry ______ that spread diseases.

  1. plants

  2. animals

  3. micro organisms

  4. dirt
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sewage contains organic waste and various pathogens, including bacteria, viruses, and protozoa, which are microorganisms responsible for spreading water-borne diseases.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Waste water from industries contain

  1. microbes

  2. poisonous substances

  3. oil

  4. minerals
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Industrial wastewater often contains heavy metals, toxic chemicals, and other hazardous substances that are harmful to the environment and human health.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Which parameter is very important in sewage treatment?

  1. Temperature

  2. Chemical

  3. Decomposition

  4. All of them
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Temperature is a critical parameter in sewage treatment because it significantly affects the rate of biological decomposition and the solubility of oxygen. While chemicals and decomposition are important, temperature regulates these biological and chemical processes.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Sewage consist of 99.9% of

  1. Oxygen

  2. Nutrients

  3. Waste

  4. Water
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Domestic sewage is composed primarily of water, typically accounting for about 99.9 percent of the total volume. The remaining small fraction consists of dissolved and suspended solids, organic matter, and other contaminants.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

In a waste water treatment, plants are examples of

  1. Natural Ecosystem

  2. Artificial Ecosystem

  3. Lotic

  4. lentic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the context of wastewater treatment, constructed wetlands or specific plant-based treatment systems are considered artificial ecosystems. They are engineered by humans to perform specific ecological functions like purification.

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Which of the following are correctly matched ? 
1. Arsenic poisoning - Black-foot disease
2. Secondary effluent treatment - Biological process 
3. Pyrolysis - Waste disposal
4. Tubifex - Water pollution indicator 
5. Biomagnification - Degradable pollutants 

  1. 1, 2, 3 and 5

  2. 1, 3, 4 and 5

  3. 2, 3, 4 and 5

  4. 1, 2, 4 and 5

  5. 1, 2, 3 and 4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Biomagnification refers to increase in concentration of the toxicant at successive trophic levels. This happens because a toxic substance accumulated by an organism cannot be metabolised or excreted, and is thus passed on to the next higher trophic level. This phenomenon is well known for mercury and DDT. 

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

The domestic sewage in large cities

  1. Has a high BOD level, as site containes both aerobic and anaerobic bacteria.

  2. Is processed by aerobic and then anaerobic bacteria in the secondary treatment in the Sewage Treatment Plants (STPs).

  3. When treated in STPs does not really require the aeration step as the sewage contains adequate oxygen.

  4. Has very high amounts of suspended solids and dissolved salts.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Secondary (biological) treatment is the method to remove the dissolved organic matter that escapes primary treatment. This is achieved by microbes consuming the organic matter as food, and converting it to carbon dioxide, water, and energy for their own growth and reproduction. The biological process is then followed by additional settling tanks to remove more of the suspended solids. In this method, waste water first treated with microbes aerobically and anaerobically in anaerobic digester tank.
Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Sewage water is purified for recycling by the action of 

  1. Light

  2. Micro-organisms

  3. Aquatic plants

  4. Fishes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Domestic sewage primarily contains biodegradable organic matter, which readily decomposes by bacteria and other micro-organisms, which can multiply using these organic substances as substrates and hence utilise some of the components of sewage. It is possible to estimate the amount of biodegradable organic matter in sewage water by measuring biochemical oxygen demand (BOD).  

Microorganisms involved in biodegradation of organic matter in the receiving water body consume a lot of oxygen, and as a result there is a sharp decline in dissolved oxygen downstream from the point of sewage discharge. This causes mortality of fish and other aquatic creatures. 

Multiple choice biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

Which is correctly matched?
1. Arsenic poisoning- Black foot disease.
2. Secondary Effluent treatment- Biological process.
3. Pyrolysis- Solid soil waste disposal
4. Tubifex- Water pollution indicator
5. Biomagnification- Degradable pollutants

  1. 1, 2, 3, 5

  2. 1, 3, 4, 5

  3. 2, 3, 4, 5

  4. 1, 2, 3, 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Biomagnification refers to increase in concentration of the toxicant at successive trophic levels. This happens because a toxic substance accumulated by an organism cannot be metabolised or excreted (non degradable), and is thus passed on to the next higher trophic level. This phenomenon is well known for mercury and DDT. Biological magnification often refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain.

Therefore, the correct answer is option D.