Wastewater Story - Chapter 18: Class 7 Science NCERT Book (PDF)

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 sewage.

⇒ 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

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