How is activated sludge formed from Class 7?

After the aerator tank, microbes and human waste settle down and form activated sludge. The activated sludge is about 97\% water. The water is removed by sand drying beds or machines. Dried sludge is used as manure, returning organic matter and nutrients to the soil.

How are sludge and activated sludge formed during?

(i) It is sludge formed during primary sewage treatment. It is sludge formed during secondary sewage treatment.

How does activated sludge formed during sewage treatment?

In activated sludge process wastewater containing organic matter is aerated in an aeration basin in which micro-organisms metabolize the suspended and soluble organic matter. Part of organic matter is synthesized into new cells and part is oxidized to CO2 and water to derive energy.

What are the steps of activated sludge process?

Treatment Steps

1. Step 1: Screening and Pumping.
2. Step 2: Grit Removal.
3. Step 3: Primary Settling.
4. Step 4: Aeration / Activated Sludge.
5. Step 5: Secondary Settling.
6. Step 8: Oxygen Uptake.
7. Sludge Treatment.

What is sludge very short answer?

Solution: Sludge is human waste (like faeces) in waste water left during sewage treatment. Since it is organic waste, it is used to produce biogas and manure. Sludge is collected by a scrapper. It is transferred to a separate tank where it is decomposed by the anaerobic bacteria.

What is activated sludge 12?

Activated sludge comprises a mixture of microbes and suspended particles. In the primary treatment, the bacterial culture is produced to break down organic to carbon dioxide, water as well as other inorganic ions. Many aspects of organic matter in the wastewater system act as a source of food for such microbes.

What is produced during sewage treatment?

Methane, Hydrogen sulfide, Carbon dioxide, and Hydrogen: These gases are all part of the biogas produced during the sewage treatment.

What is the use of activated sludge Class 12?

Powered sludge systems have the ability to treat black water, brown water, gray water, fecal sludge, and industrial effluent as long as the contaminants to be managed are environmentally friendly.

Why a small part of the activated sludge is pumped back into aeration tank during secondary treatment of sewage?

A small part of activated sludge is pumped into large tanks called anaerobic sludge digesters. A small part of activated sludge is pumped back Into the aeration tank to serve as inoculum.

Why is activated sludge called activated?

The activated sludge process was developed in England in 1914 and was so named because it involved the production of an activated mass of microorganisms capable of aerobically stabilizing the organic content of a waste.

What are the 4 stages of wastewater treatment?

Four common ways to treat wastewater include physical water treatment, biological water treatment, chemical treatment, and sludge treatment. Let us learn about these processes in detail.

What is grit removal?

Grit removal is the process used to remove sand, silt and grit from water. Grit removal can also be used to remove sand from river water intakes prior to processing for potable water, use in industrial applications to remove fine abrasives, as well as being used to remove grit entrained in sludge.

Why is the activated sludge process called so?

Activated sludge process was developed in England in 1914 and was so named because it involved the production of an activated mass of microorganisms capable of aerobically stabilizing the organic content of a waste water.

What does activated sludge mean?

Activated sludge. The activated sludge process is a type of wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa .

How does activated sludge work?

How Activated Sludge Works. The activated sludge is aerated to dissolve oxygen which allows the organic matter ( BOD ) to be utilised by the bugs. The organic matter, or food, sticks to the activated sludge. The oxygen dissolved in the water allows the bugs to use the food (BOD) and also to change the ammonia to nitrate.

How do you avoid sludge bulking in activated sludge process?

To avoid sludge bulking some of the flow that enters the reactor can be bypassed , recycle ratio can be increased , lime or soda can be added to the reactor or the re-aeration rate increased. How do you increase SVI in activated sludge?