Biology Microbes in Human Welfare part 10 (Secondary Sewage Treatment) class 12 XII

TL;DR

In the secondary treatment of sewage, aerobic microbes consume organic matter to reduce its polluting potential.

Transcript

Hello friends this video on microbes in human welfare part 10 is brought to you by exam.com no more fear from exam so now we will talk about the secondary treatment of sewage now what happens is the influent from primary treatment is passed on for secondary treatment as I mentioned so influent is now free of all the solid particles and all visible ... Read More

Key Insights

• 🦠 Secondary treatment involves constant agitation and aeration in aeration tanks to promote the growth of aerobic microbes, which consume organic matter.
• ❓ Biochemical oxygen demand (BOD) is used to measure the organic content in wastewater and determine the extent of sewage treatment.
• 🥺 The reduction of organic matter in wastewater leads to a decrease in polluting potential and safer disposal into water bodies.
• 💁 The sludge formed during secondary treatment is separated, with a portion recycled as a starter and the remaining sludge sent to anaerobic sludge digesters.
• 🦠 Anaerobic sludge digesters break down microbes in the sludge and produce biogas, a renewable energy source.
• 💦 The overall goal of sewage treatment is to reduce the polluting potential of wastewater and ensure safe disposal into water bodies.
• 🖐️ Microbes, particularly aerobic organisms, play a crucial role in the secondary treatment of sewage.

Questions & Answers

Q: What is the purpose of secondary treatment in sewage treatment?

The secondary treatment aims to further reduce the organic matter in wastewater by promoting the growth of aerobic microbes, which consume organic matter and improve water quality.

Q: How does the constant agitation and aeration in aeration tanks contribute to sewage treatment?

The constant agitation and aeration in aeration tanks provide oxygen to support the growth of aerobic microbes, which are responsible for the breakdown of organic matter in the wastewater.

Q: What is biochemical oxygen demand (BOD), and why is it important in sewage treatment?

BOD measures the amount of oxygen needed by aerobic organisms to break down organic material in water. It assesses the level of organic content in the wastewater and indicates the extent of sewage treatment. Lower BOD values indicate reduced polluting potential.

Q: What happens to the sludge formed during the secondary treatment of sewage?

The sludge formed during secondary treatment is separated from the effluent in a settling tank. A portion of the sludge is reused as a starter in the aeration tanks, while the remaining sludge is sent to anaerobic sludge digesters, where anaerobic bacteria break down the microbes present and produce biogas.

Summary & Key Takeaways

• In secondary treatment, the influent from primary treatment, free of solid particles, undergoes constant agitation and aeration in aeration tanks.

• Vigorous growth of aerobic microbes occurs due to the availability of oxygen, and these microbes consume organic matter in the wastewater.

• The reduction of organic matter is measured using biochemical oxygen demand (BOD), and the secondary effluent is disposed of while the activated sludge is further treated.