This PSEB 7th Class Science Notes Chapter 18 Wastewater Story will help you in revision during exams.
PSEB 7th Class Science Notes Chapter 18 Wastewater Story
→ Sewage is liquid waste, most of it is water that has dissolved and suspended impurities. These impurities are called contaminants.
→ An underground network of pipes that carry wastewater from a home to a point of disposal is called Sewerage.
→ Sewage is transported through the closed pipes to the wastewater treatment plants where pollutants are separated and reformed and then flow into rivers and oceans.
→ During wastewater treatment pollutants are separated by physical, chemical, and biological methods.
→ Sludge is a solid that settles to the bottom during water purification.
→ Wastewater treatment co-products are sludge and biogas.
→ A manhole is a lid-covered open space through which a person can enter and can check the sewerage system.
→ Open defecation is a breeding ground for flies, mosquitoes, and other insects that cause many diseases.
→ Do not throw oil, ghee, grease, etc. in a drain or in the open. Doing so will make drain chock.
→ Throw trash only in the bin (dustbin).
→ Pollutants: Dissolved and suspended impurities in dirty water are called pollutants.
→ Sewerage: A network of small and large pipes that carry wastewater to the drainage area.
→ Manhole: Large open mouth holes are made at every 50-60 meters of the sewerage system.
→ Individual who enters the sewage can check and remove sewage problem if any.
→ Water Treatment Plant: A place where impurities are separated from wastewater.
→ Water Treatment: The process of separating impurities from wastewater is called water treatment.
→ Sludge is the solid that settles in the sewage water purification tank.
→ Septic tank: This is a small system of sewage treatment containing monoaerobic bacteria that remove waste products. It has connections with main sewage pipes.