Tag: biology

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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

Which of the following is correct for sewage discharge in river?

  1. At the discharge point B.O.D is high and fishes die

  2. At the discharge point D.O. is high

  3. B.O.D increase downstream ion river

  4. From the discharge 50 KM away, Fishes ,die
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When sewage is discharged into a river, the high organic load increases the biological oxygen demand (BOD) as microorganisms decompose the waste, leading to a drop in dissolved oxygen (DO) and the death of aquatic organisms like fish.

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

Select the correct statement from the following.

  1. Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria

  2. Biogas is produced by the activity of aerobic bacteria on animal waste

  3. Methano bacterium is an aerobic bacterium found in rumen of cattle

  4. Biogas, commonly called as global gas, is pure methane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

1. The effluent from aeration tank is passed into a settling tank where the aerobic bacterial ‘flocs’ are allowed to sediment and the sediment is called activated sludge.

2. Biogas is produced by the activity of anaerobic bacteria on activated sludge.
3. Methano bacterium is an anaerobic bacteria found in rumen of cattle.
4. Biogas is a mixture of gases such as methane, hydrogen sulphide and carbon dioxide.
So, the correct option is 'Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria'.

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

Tertiary treatment of sewage is also known as

  1. Advance Treatment

  2. Preliminary Treatment

  3. Secondary Treatment

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

Tertiary treatment is the final stage of sewage treatment, involving advanced processes to remove remaining nutrients, chemicals, or pathogens, often referred to as advanced treatment.

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

Secondary treatment reduces bacterial load, ranges from

  1. 90-100%

  2. 80-98%

  3. 40-60%

  4. 10-30%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Secondary biological treatment is highly effective at reducing the organic load and bacterial content of sewage, typically achieving a reduction in the range of 80 to 98 percent.

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

Hard water does not easily produce lather with soap because it contains:

  1. Only $Mg^{2+}$ ions
  2. Only $Ca^{2+}$ ions
  3. Both $Mg^{2+}$ and $Ca^{2+}$ ions
  4. Both $Na^+$ and $K^+$ ions
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hard water contains dissolved calcium and magnesium salts. These ions react with soap to form insoluble precipitates (scum), preventing the formation of lather.

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 biological treatment of waste water makes use of

  1. Aerobic bacteria and fungi

  2. Anaerobic bacteria and algea

  3. Aerobic and anaerobic bacteia

  4. Anaerobic bacteria and Eucalyptus leaves
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Aerobic digestion of waste is the natural biological degradation and purification process in which bacteria that thrive in oxygen-rich environments break down and digest the waste. During oxidation process, pollutants are broken down into carbon dioxide ( CO$ _{2}$ ), water (H$ _{2}$O), nitrates, sulphates and biomass (microorganisms). By operating the oxygen supply with aerators, the process can be significantly accelerated. Of all the biological treatment methods, aerobic digestion is the most widespread process that is used throughout the world. Anaerobic digestion is a complex biochemical reaction carried out in a number of steps by several types of microorganisms that require little or no oxygen to live. During this process, a gas that is mainly composed of methane and carbon dioxide, also referred to as biogas, is produced. The amount of gas produced varies with the amount of organic waste fed to the digester and temperature influences the rate of decomposition and gas production. Wastewater pollutants are transformed into methane, carbon dioxide and smaller amount of bio-solids. The biomass growth is much lower compared to those in the aerobic processes. They are also much more compact than the aerobic bio-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

Physical treatment for the industrial wastes include sedimentation and filtration.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids (liquids or gases) by interposing a medium through which only the fluid can pass. The fluid that passes through is called the filtrate.  Oversize solids in the fluid are retained, but the separation is not complete; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size and filter thickness).
Sedimentation is a physical water treatment process using gravity to remove suspended solids from water. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans.
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 purification is performed by 

  1. Microbes

  2. Fertilisers

  3. Antibiotics

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

Sewage treatment is done in three stages: primary, secondary and tertiary treatment. Secondary treatment removes dissolved and suspended biological matter, using microorganisms in a controlled environment. Most secondary treatment systems use aerobic bacteria, which consume the organic components of the sewage (sugar, fat, and so on). Some systems use fixed film systems, where the bacteria grow on filters, and the water passes through them. Suspended growth systems use activated sludge, where decomposing bacteria are mixed directly into the sewage. Because oxygen is critical to bacterial growth, the sewage is often mixed with air to facilitate decomposition.

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

Select the correct statement from the following.

  1. Methanobacterium is aerobic bacterium found in rumen of cattle.

  2. Biogas, commonly called gobar gas, is pure methane.

  3. Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

  4. Biogas is produced by the activity of aerobic bacteria on animal waste.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Methanobacterium  are anaerobic organisms.
Biogas refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen.
Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.
Biogas can be produced by anaerobic digestion with anaerobic bacteria.
Thus, the correct answer is option (C), 'Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria'.