Tag: sewage treatment

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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

Primary treatment reduces solids, ranges from

  1. 20-60%

  2. 10-50%

  3. 20-70%

  4. 40-60%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Primary treatment is a physical process that involves sedimentation to remove suspended solids. Standard engineering references typically cite that primary treatment removes approximately 40 to 60 percent of suspended solids.

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

What involved in wastewater final treatment?

  1. BOD

  2. Chlorination

  3. Sedimentation

  4. All of above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorination is a common final treatment process used to disinfect wastewater by killing pathogens and bacteria before the water is discharged or reused. While BOD and sedimentation are part of the treatment, they occur in earlier stages.

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 contains algae, fungi, bacteria and

  1. Crocodiles

  2. Snakes

  3. Rotifers

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

Wastewater contains a diverse microbial community, including bacteria, fungi, algae, and protozoa like rotifers. Rotifers are microscopic multicellular organisms commonly found in wastewater treatment systems.

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

During sewage treatment the microorganisms participate under which step?

  1. Primary

  2. Secondary

  3. Teritiary

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sewage treatment generally involves three stages, called primary, secondary and tertiary treatment. 

Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. 
Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment. 
Tertiary treatment allows rejection into a highly sensitive or fragile ecosystem like estuaries, low-flow rivers, coral reefs etc. 

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.

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

A sewage treatment process in which a portion of the decomposer bacteria present in the waste is recycled into the beginning of the process, is called as

  1. Primary treatment

  2. Tertiary treatment

  3. Activated sludge treatment

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

The activated sludge process is a process for treating sewage and industrial wastewaters using air and a biological floc composed of bacteria and protozoa. Activated sludge refers to a mass of microorganisms cultivated in the treatment process to break down organic matter into carbon dioxide, water, and other inorganic compounds. 

The activated sludge process has three basic components: 
1) A reactor in which the microorganisms are kept in suspension, aerated, and in contact with the waste they are treating,
2) Liquid-solid separation and 
3) A sludge recycling system for returning activated sludge back to the beginning of the process. 
Therefore, the correct answer is option C.

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

A natural disaster caused due to insufficient water for agriculture is called

  1. flood

  2. draught

  3. famine

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

A famine is a widespread scarcity of food, often caused by crop failure due to factors like insufficient water for agriculture. While drought is the lack of water, famine is the resulting disaster involving food shortage.