Question

The biological treatment of wastewater makes use of
A. Aerobic bacteria and fungi
B. Anaerobic bacteria and algae
C. Aerobic and anaerobic bacteria
D. Anaerobic bacteria and Eucalyptus leaves

Answer 1

Hint: Human excreta is the major component in wastewater. This municipal waste-water is also called sewage. And also organic matter and microbes are in large amounts. Many of which are pathogenic. Do you know how this huge quantity of sewage or urban wastewater is disposed of daily. This cannot be discharged into natural water bodies like rivers and streams directly. Before disposal, hence, sewage is treated in sewage treatment plants (STPs) to make it less polluting. Heterotrophic microbes naturally present in the sewage water will treat the sewage water itself.

Complete answer:
-Aerobic bacteria and fungi: Aerobic bacteria digest the waste from biological degradation and purification process. Aerobic digestion is the most widespread treatment used throughout the world, whereas, in fungal wastewater treatment they produce biomass, it has potentially much higher value than the bacterial sludge process.
-Anaerobic bacteria and algae: Anaerobic digestion is complex and it carries out many biochemical reactions involving several types of microorganisms. During this process carbon dioxide, methane gases are composed, referred to as biogas, is produced. In Wastewater treatment algae are the significant organism to purify biological wastewater.
-Anaerobic and anaerobic bacteria: The large aeration tanks get the primary effluent in. The air is pumped into it where it is constantly agitated mechanically. The vigorous growth of useful aerobic microbes into flocs will get allowed. While growing, these microbes consume the major part of the organic matter in the effluents. This significantly refuses the BOD (biological oxygen demand) of the effluent. Anaerobically growing other kinds of bacteria, digesting the bacteria and fungi in the sludge. Bacteria produce a mixture of gases such as methane, hydrogen sulfide, and carbon dioxide during this digestion. These gases form biogas and can be used as a source of energy as it is inflammable.
-Anaerobic bacteria and Eucalyptus leaves: Anaerobic digestion is complex and it carries out many biochemical reactions involving several types of microorganisms. During this process carbon dioxide, methane, hydrogen gases are produced referred to as biogas. Eucalyptus can remove the toxic metals which are present in the water.
So, the correct answer is “Option C”.

Note:
Bacteria are referred to as unicellular, prokaryotic help in decomposing organic matter and help in nitrogen fixation using atmospheric nitrogen. When it is in the liquid medium seen on the surface of the medium.
Based on the types of respiration they are classified into two types a) aerobic bacteria b) anaerobic bacteria.
-Bacteria that grow in the presence of oxygen called aerobic bacteria.
Aerobic bacteria can detoxify oxygen in the presence of enzymes. Example: Nocardia, Bacillus, etc.
-Bacteria that grow in the absence of oxygen called anaerobic bacteria.
Anaerobic bacteria cannot detoxify oxygen. When it is in the liquid medium seen in the bottom of the medium
Example: E.coli, Bacteroids, etc.