Test: Waste Water Story - Class 7 MCQ

The process of waste treatment is called as sewage treatment to remove harmful substance from water to make it portable.

Yes, it's true! Wastewater treatment involves different processes like physical, chemical, and biological methods. These processes help in cleaning the water by removing things like dirt, sand, and even tiny living things that can make the water dirty.

Biodegradable wastes are generally organic in nature obtained from plant and animals.

Bar screens are used to remove large objects like rags, sticks, cans, and plastic packets from wastewater as it passes through them.

Sewage is wastewater released by homes, industries, hospitals, offices and other users. It also includes rainwater that has run down the street during a storm or heavy rain. The water that washes off roads and rooftops carries harmful substances with it. Sewage is a liquid waste. Most of it is water, which has dissolved and suspended impurities.

Vegetable peels, cotton cloths and paper are plant products and organic wastes while DDT is manmade inorganic substance used as pesticides.

• In the process of water treatment at a filtration plant, they typically do not use filter paper. Instead, they use layers of sand, fine gravel, and medium gravel in the filtration process.
• Filter paper is often used in science experiments or smaller-scale filtration processes. But in large filtration plants, they use different materials like sand and gravel to filter the water.

Drains get blocked by a combination of substances, leading to clogs. The correct answer is C: All of these. Here's why:

- Hair: Accumulates in drains, combining with other substances.
- Soap: Residue can solidify, trapping debris.
- Cooking oil and fats: Harden over time, narrowing drain passages.

By choosing option C, you acknowledge that all these factors contribute to drain blockages, emphasizing the importance of regular maintenance to prevent clogs effectively.