Consider the following statements regarding "Vermi-cakes": 1. They are a byproduct of vermi-processing toilets. 2. They are hazardous waste that must be incinerated. 3. They are a resource needed for soil. Which of the statements given above is/are correct?

The correct option is (c). Explanation Vermi-processing toilets are a form of sustainable sanitation where human excreta is treated using earthworms. This biological process decomposes organic waste into stable, nutrient-rich material. Statement-wise Analysis - Statement 1 is Correct: Vermi-cakes are the end product (byproduct) of the digestion of human excreta by earthworms in vermi-processing toilets. The worms consume the organic matter and convert it into compost. - Statement 2 is Incorrect: Vermi-cakes are not hazardous waste. The vermi-processing method stabilizes the waste and significantly reduces pathogens, making the end product safe to handle. Incineration is not required. - Statement 3 is Correct: Vermi-cakes are rich in nutrients and organic matter. They act as high-quality manure or fertilizer, making them a valuable resource for improving soil fertility. Key Takeaway: Vermi-processing toilets utilize earthworms to convert human waste into safe, nutrient-rich manure (vermi-cakes), thereby recycling waste into a resource for soil.

NCERT Class 7 Environment & Ecology — Chapter 2: Wastewater story

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Consider the following statements regarding "Vermi-cakes":

They are a byproduct of vermi-processing toilets.
They are hazardous waste that must be incinerated.
They are a resource needed for soil.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 and 2 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (c).

Explanation

Vermi-processing toilets are a form of sustainable sanitation where human excreta is treated using earthworms. This biological process decomposes organic waste into stable, nutrient-rich material.

Statement-wise Analysis

Statement 1 is Correct: Vermi-cakes are the end product (byproduct) of the digestion of human excreta by earthworms in vermi-processing toilets. The worms consume the organic matter and convert it into compost.
Statement 2 is Incorrect: Vermi-cakes are not hazardous waste. The vermi-processing method stabilizes the waste and significantly reduces pathogens, making the end product safe to handle. Incineration is not required.
Statement 3 is Correct: Vermi-cakes are rich in nutrients and organic matter. They act as high-quality manure or fertilizer, making them a valuable resource for improving soil fertility.

Key Takeaway:
Vermi-processing toilets utilize earthworms to convert human waste into safe, nutrient-rich manure (vermi-cakes), thereby recycling waste into a resource for soil.

Your note

More from Chapter 2: Wastewater story

With reference to the composition of sewage, consider the following statements: 1. It is a liquid waste consisting entirely of dissolved impurities. 2. It contains nutrients such as phosphorus and nitrogen. 3. It is devoid of any saprophytic or disease-causing bacteria. Which of the statements given above is/are correct?

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Consider the following statements regarding the impurities found in sewage: 1. Urea and pesticides are classified as organic impurities. 2. Nitrates and phosphates are classified as organic impurities. 3. Vegetable waste and animal waste are classified as organic impurities. Which of the statements given above is/are correct?

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Consider the following statements regarding the physical treatment of wastewater: 1. Bar screens are used to remove large objects like rags and sticks. 2. The speed of wastewater is increased in the grit and sand removal tank to facilitate filtration. 3. Sedimentation tanks are designed to increase the flow speed to prevent settling of solids. Which of the statements given above is/are correct?

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With reference to unit operations used in wastewater treatment, the role of a skimmer is to:

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Consider the following statements regarding "Activated Sludge": 1. It consists of suspended microbes that settle at the bottom of the tank after aeration. 2. It contains a very low percentage of water, being mostly solid. 3. A part of it is pumped back into the aeration tank to serve as an inoculum. Which of the statements given above is/are correct?

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The correct option is (c).

Explanation

Vermi-processing toilets are a form of sustainable sanitation where human excreta is treated using earthworms. This biological process decomposes organic waste into stable, nutrient-rich material.

Statement-wise Analysis

Statement 1 is Correct: Vermi-cakes are the end product (byproduct) of the digestion of human excreta by earthworms in vermi-processing toilets. The worms consume the organic matter and convert it into compost.
Statement 2 is Incorrect: Vermi-cakes are not hazardous waste. The vermi-processing method stabilizes the waste and significantly reduces pathogens, making the end product safe to handle. Incineration is not required.
Statement 3 is Correct: Vermi-cakes are rich in nutrients and organic matter. They act as high-quality manure or fertilizer, making them a valuable resource for improving soil fertility.

Key Takeaway:
Vermi-processing toilets utilize earthworms to convert human waste into safe, nutrient-rich manure (vermi-cakes), thereby recycling waste into a resource for soil.