Tag: basics of water pollution

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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

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'.

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

One of the method for purification of water is sedimentation.

  1. True

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

The sedimentation process involves the settling down of particles suspended in water under the effect of gravity. The particles that settle down are known as sediment. In purification of water sedimentation process helps in reducing the concentration of particles in suspension. It is the first step used in the primary treatment of sewage water. 

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

Biological treatment in sewage treatment plant is also known as

  1. Primary treatment

  2. Secondary treatment

  3. Tertiary treatment

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

Secondary treatment in a sewage plant relies on the activity of aerobic and anaerobic microorganisms to break down organic matter, hence it is called biological 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

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.