Chapter 18 (Wastewater Story) of Class 7 Science NCERT Book (PDF) is available here for download in PDF format. Download now and prepare for CBSE Class 7th Science exam.

Created On: Jul 19, 2021 18:16 IST

NCERT

NCERT

Chapter 18 (Wastewater Story) of Class 7 Science NCERT Book (PDF) is available here for download in PDF format. Download now & prepare for CBSE Class 7 Science exam in academic session 2021-22. It is one of the most important chapters of the CBSE Class 7th Science NCERT textbook & many essential questions are framed from this chapter.

Download NCERT Book Class 7 Science (PDF) Chapter 18 – Wastewater Story

Snapshot from Chapter 18 of Class 7 Science NCERT Textbook:

Important topics of this chapter:

Aerobic bacteria

Anaerobic bacteria

Biogas

Contaminant

Sanitation

Sewage

Sewer

Sewerage

Sludge

Wastewater

Aeration

Important points of this chapter:

Used water is wastewater. Wastewater could be reused.

Wastewater is generated in homes, industries, agricultural fields and in other human activities. This is called sewerage.

Sewage is a liquid waste which causes water and soil pollution.

Wastewater is treated in a sewage treatment plant.

Treatment plants reduce pollutants in wastewater to a level where nature can take care of it.

Where underground sewerage systems and refuse disposal systems are not available, the low cost on-site sanitation system can be adopted.

By-products of wastewater treatment are sludge and biogas.

Open drain system is a breeding place for flies, mosquitoes and organisms which cause diseases.

We should not defecate in the open. It is possible to have safe disposal of excreta by low cost methods

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