Olympiad Test: Waste Water Story - Class 7 MCQ

Cardboard, cotton cloth and leather shoes are biodegradable while glass bottle is non-biodegradable item.

Backward composting is an example of source reduction of waste as waste is composted in field to make manure.

Water from a sewage system: This is considered wastewater. Wastewater is used water that has been affected by domestic, industrial, commercial, or agricultural activities. It contains waste products such as human waste, food scraps, oils, soaps, and chemicals. This water needs to be treated before it can be safely released back into the environment or reused.

Those substance that are easily broken into simpler substances by action of bacteria are called biodegradable. Orange peels is biodegradable.

Addition of harmful substance in water leads to water pollution as it contains biological, chemical and physical pollutants.

Water chlorination is the process of adding chlorine or chlorine compounds such as sodium hypochlorite to water. This method is used to kill bacteria, viruses and other microbes in water. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid.

Passing chlorine gas through drinking water to disinfect it is called chlorination. Chlorination kills the microbes present in water.

Household garbage includes crockery pieces, dal packets and vegetable peels. Cow dung is a farm garbage.

Sewage is mainly a liquid waste.Sewage is a type of wastewater that is produced from a community of people. It is characterized by volume or rate of flow, physical condition, chemical and toxic constituents, and its bacteriologic status . It consists mostly of grey water.

The network of drainage pipe to carry waste water is called sewer system to remove waste water from houses.

Water obtained from water work is chlorinated to kills the germ present in it.

After the treatment of water by sewage treatment, water is released to water bodies.

Sewage treatment involves many stages like primary treatment, secondary treatment and tertiary treatment. The last stage in treatment os sewage is chlorination.

Open drain because unhygienic condition as it provides breeding ground for malaria and other insect carrying pathogen.

jaundice is caused by using contaminated water. Jaundice affects the liver of person.

During sewage treatment, solid wastes are also generated. This waste can be used as manure.

A pathogen or infectious agent is a biological agent that causes disease or illness to its host.

To remove floating waste in sewage bar screen is used during primary treatment.

Stone, girt and other solid parts present in sewage forms the sludge. It is separated by sedimentation.

Adding air to treated water is called aeration. Aeration increases the aerobic bacteria in water to consume the organic wastes.