A. Choose the correct option.
1. Waste is produced from various activities such as
a. industrial b. agriculture c. domestic activities
d. all of these
Answer. d. all of these
2. Which one of these is a biological process of treating wastewater?
a. Screening of wastes b. Digestion of wastes
C. Disinfecting water d. None of these
Answer. b. Digestion of wastes
3. Screens consisting of upright bars are found in
a. primary process b. secondary process
c. tertiary process d. manhole
Answer. a. primary process
4. Sludge can be converted into useful substances through
a. incinerating b. dewatering
c. composting and anaerobic digestion d. all of these
Answer. d. all of these
5. Improper management of sewage results in
a. waterborne epidemics b. eutrophication
c. water pollution d. all of these
Answer. d. all of these
6. Which of the following destroy bacteria and disinfects water?
a. primary process b. secondary process
c. tertiary process d. none of these
Answer. c. tertiary process
B. Fill in the blanks with the correct words.
1. Wastewater generated from industries contains harmful. paints/ pesticides).
Wastewater generated from industries contains harmful paints/pesticides.
2. Eutrophication is the bloom of._______
(algae/bacteria).
Eutrophication is the bloom of algae.
3. In primary treatment of sewage, the material that rises to the top is called.. (sludge/scum).
In primary treatment of sewage, the material that rises to the top is called scum.
4. The primary treatment process is a ._____(mechanical/biological)
The primary treatment process is mechanical.
5. (Earthworms/Bacteria)_____ are used to convert compost in vermicomposting toilets.
(Earthworms/Bacteria) earthworms are used to convert compost in vermicomposting toilets.
C. Name the following:
1. The discharge of liquid waste into water bodies
Answer. Sewage discharge
2. Wastewater containing dissolved and suspended impurities
Answer. Sewage
3. The material that rises to the top in sedimentation tanks during primary process
Answer. Scum
4. The water that comes out of the sedimentation tanks after the completion of primary process
Answer. Effluent
5. The biological process in which the organic matter in sewage is broken down with the help of bacteria
Answer. Biological decomposition
6. A process in which the sludge is burnt into ashes
Answer. Incineration
- Describe sources of wastewater.
Answer. Wastewater comes from different sources, including households (kitchens, bathrooms, and toilets), industries (factories releasing chemicals and pollutants), agriculture (runoff containing fertilizers and pesticides), and commercial establishments like hotels and hospitals.
- Explain the term eutrophication.
Answer. Eutrophication happens when excess nutrients, such as nitrogen and phosphorus, enter water bodies, causing excessive growth of algae. This leads to oxygen depletion in the water, harming aquatic life.
- What is a sewer system?
Answer. A sewer system is a network of underground pipes that transport wastewater from homes, industries, and businesses to treatment plants, where harmful substances are removed before the water is released into the environment.
- Describe the various processes used for treating wastewater.
Answer. Wastewater treatment includes:
Primary treatment: Removal of large particles and sediments through screening and sedimentation.
Secondary treatment: Biological treatment using bacteria to break down organic matter.
Tertiary treatment: Disinfection using chemicals or filtration to make water safe for reuse or disposal.
- Differentiate between primary and secondary processes used for wastewater treatment.
Answer. Primary process: A mechanical process that removes solid waste through sedimentation.
Secondary process: A biological process where bacteria break down organic matter.
- Briefly explain the tertiary process used for treating wastewater.
Answer. The tertiary process involves the final stage of treatment where wastewater is disinfected using chemicals like chlorine, ultraviolet light, or advanced filtration systems to remove any remaining contaminants before reuse or discharge.
- How can treated wastewater be used?
Answer. Treated wastewater can be used for irrigation, industrial cooling, recharging groundwater, and even for non-drinking purposes like flushing toilets and street cleaning.
- How can we convert sludge into useful substances?
Answer. Sludge can be converted into compost for agriculture, used to produce biogas for energy, or processed into fertilizers through anaerobic digestion.
- List out a few measures that can be adopted to control the generation of sewage at home.
Answer. Avoid wasting water while bathing, washing, or cooking.
Properly dispose of kitchen waste instead of flushing it down the sink.
Reduce the use of harmful chemicals in cleaning.
Fix leaking taps and pipes to minimize wastewater generation.
Discuss the problems faced due to improper management of wastes.
Answer. Improper waste management leads to water pollution, the spread of diseases, foul smells, and contamination of drinking water sources. It also results in environmental damage like eutrophication and harm to aquatic life.
How can sewage be disposed of through septic tanks?
Answer. Septic tanks are underground tanks that collect and treat sewage from homes. Solid waste settles at the bottom, while bacteria break down the waste. The treated water is absorbed into the soil through a soak pit.
What are vermicomposting toilets?
Answer. Vermicomposting toilets use earthworms to break down human waste into compost. This method is eco-friendly and helps convert waste into useful organic matter.
How can biogas plants be used for sewage disposal?
Answer. Biogas plants use bacteria to break down sewage and organic waste, producing methane gas that can be used for cooking or generating electricity. The leftover sludge can be used as fertilizer.
What should be kept in mind while providing sanitation facilities to the public at places with huge gatherings?
Answer. Ensure proper waste disposal and regular cleaning.
Provide adequate water supply and handwashing stations.
Install bio-toilets or composting toilets to manage waste effectively.
Have a proper drainage system to prevent contamination.
Why should garbage not be thrown on the roads?
Answer. Throwing garbage on roads leads to pollution, spreads diseases, clogs drainage systems, and creates an unhygienic environment. Proper waste disposal keeps surroundings clean and protects public health.