NCERT Solutions for Class 7 Science Chapter 18
Important NCERT Questions
7th Chapter 18 Wastewater Story
NCERT Books for Session 2022-2023
CBSE Board and State Board
Questions No: 2
What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
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Sewage is a liquid waste which has water as its largest component along with various types of impurities like waste water from houses, offices, factories, hospitals etc., is called sewage. It has a complex mixture containing suspended solids, organic and inorganic impurities, nutrients, saprotrophic and disease causing bacteria and other microbes.
Discharging untreated sewage into rivers or seas will pollute the water resources. Contaminated water is dangerous for aquatic plants and animals. It also spread many diseases like cholera, typhoid, polio, meningitis, malaria, dengue etc.
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Sewage is wastewater from homes, industries, and businesses. Discharging untreated sewage into rivers or seas is harmful because it contaminates water with disease-causing germs, chemicals, and pollutants. This pollution can make water unsafe for drinking and recreational activities, causing health issues like infections. It also leads to excessive plant growth, reducing oxygen in water, and harming aquatic life. Moreover, it disrupts ecosystems, threatening the environment and biodiversity. Proper treatment of sewage is crucial to prevent these harmful effects on water bodies and living organisms.