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Water, Our Lifeline
Dirty Water
- We all use water at home, making it dirty.
- This dirty water is called wastewater.
- Wastewater includes water from sinks, showers, toilets, and laundries.
Water, Our Lifeline
- Clean water is essential for humans.
- Many people lack access to safe drinking water.
- Over one billion people can’t get clean water, causing diseases and deaths.
- Some people walk long distances to get clean water.
Causes of Water Scarcity
- Population growth
- Pollution
- Industrial development
- Mismanagement
Global Efforts
- The United Nations declared 2005-2015 as “Water for Life” decade.
- Aim: Reduce the number of people without access to clean water by half.
What is Sewage?
- Sewage is wastewater from homes, industries, hospitals, and offices.
- It includes rainwater runoff, which carries harmful substances.
- Sewage is mostly water with impurities.
Components of Sewage
- Organic Impurities: Human waste, animal waste, oil, urine, pesticides, and vegetable waste.
- Inorganic Impurities: Nitrates, phosphates, metals.
- Nutrients: Phosphorus and nitrogen.
- Bacteria: Causes diseases like cholera and typhoid.
- Other Microbes: Protozoans causing dysentery.
Water Freshens Up – An Eventful Journey
- Clean water comes into homes through pipes; wastewater leaves through other pipes.
- Sewers carry sewage to treatment plants.
- Manholes are placed every 50-60 meters in the sewer system.
Activities
Activity 13.1:
Make a mind map of clean water uses.
Activity 13.2:
Inspect an open drain near you and note the color, odor, and other observations.
Activity 13.3:
Study and draw the sewage route in your home/school. Count the manholes and observe organisms near open drains if possible.
Treatment of Polluted Water
Activity 13.4: Understanding Wastewater Treatment
- Materials Needed: Large glass jar, water, dirty organic matter (grass pieces, orange peels), detergent, ink or color, aerator, filter paper, funnel, sand, gravel, chlorine tablet.
Steps:
- Preparation:
- Fill a jar 3/4 with water.
- Add dirty organic matter, detergent, and a few drops of ink.
- Shake well and leave in the sun for two days.
- Before Treatment:
- Shake the jar and take a small sample in a test tube labeled “Before treatment; Sample 1”.
- Observe and smell the sample.
- Aeration:
- Use an aerator to bubble air through the jar overnight.
- Take another sample labeled “After aeration; Sample 2”.
- Filtration:
- Set up a filter with layers of sand and gravel.
- Pour aerated water through the filter.
- Collect the filtered water in a test tube labeled “Filtered; Sample 3”.
- Chlorination:
- Add a piece of chlorine tablet to the filtered water.
- Mix well and label as “Chlorinated; Sample 4”.
- Observations:
- Compare the samples by appearance and smell.
Questions:
- Changes after aeration?
- Did aeration change the odor?
- What did the sand filter remove?
- Did chlorine remove the color?
- Did chlorine have an odor? Was it worse than the wastewater odor?
Wastewater Treatment Plant (WWTP)
- Processes Involved: Physical, chemical, and biological processes to remove contaminants.
Stages:
- Bar Screens:
- Remove large objects like rags, sticks, cans, plastic packets, and napkins.
- Grit and Sand Removal:
- Slow down wastewater to settle sand, grit, and pebbles.
- Sedimentation Tank:
- Solids like faeces settle at the bottom (sludge).
- Skimmer removes floatable solids like oil and grease.
- Resulting water is called clarified water.
- Sludge Treatment:
- Sludge decomposed by anaerobic bacteria.
- Produces biogas for fuel or electricity.
- Aeration:
- Air pumped into clarified water to grow aerobic bacteria.
- Bacteria consume remaining waste.
- Activated Sludge:
- Suspended microbes settle as activated sludge.
- Water removed and sludge dried to be used as manure.
- Final Treatment:
- Treated water discharged into natural bodies or ground.
- Sometimes disinfected with chlorine or ozone.
Fun Fact
- Planting eucalyptus trees around sewage ponds can help absorb surplus wastewater and release pure water vapor.
Be an Active Citizen
- Limit the type and quantity of waste produced.
- Ensure open drains are covered to prevent unhygienic conditions.
- Approach local authorities if sewage makes the neighborhood dirty.
Better Housekeeping Practices
Minimize Waste at Home
- Do Not Throw Down the Drain:
- Cooking oil and fats: Can harden and block pipes; clog soil pores in open drains.
- Chemicals: Paints, solvents, insecticides, motor oil, medicines can kill helpful microbes.
- Solid waste: Used tea leaves, food remains, soft toys, cotton, sanitary towels choke drains.
Swachh Bharat Mission
- Launched in 2016: Aimed at proper sewage disposal and providing toilets for everyone.
Vermi-processing Toilet
- Earthworm-based Toilets: Human waste treated by earthworms, converting it to vermi cakes for soil.
Sanitation and Disease
Poor Sanitation and Health Risks
- Lack of Sewerage Facilities:
- Many people defecate in the open, on riverbeds, railway tracks, and fields.
- Untreated excreta can pollute water and soil, leading to diseases like cholera, typhoid, and dysentery.
Alternative Sewage Disposal
Low-Cost Onsite Systems
- Examples: Septic tanks, chemical toilets, composting pits.
- Use: Suitable for places without sewerage systems, hospitals, isolated buildings, or small clusters of houses.
- Hygienic On-site Disposal: Toilets connected to biogas plants for energy production.
Sanitation at Public Places
Importance of Clean Public Spaces
- Busy Places: Fairs, railway stations, bus depots, airports, hospitals.
- Waste Management: Proper disposal needed to prevent epidemics.
- Government Standards: Sanitation standards exist but are not always enforced.
Your Role
- Maintain Cleanliness: Do not litter; if no dustbin is available, carry litter home.
- Collective Action: Work together to keep the environment clean and healthy.
Conclusion
- Responsibility: Keep water sources healthy, adopt good sanitation practices.
- Be an Agent of Change: Influence others with your actions and optimism.
- Collective Power: Great things can be achieved when people work together.
Mahatma Gandhi’s Words
- Inspiration: “No one need to wait for anyone else to adopt a humane and enlightened course of action.”
Chapter Summary:
- Used water is wastewater.
- Wastewater could be reused.
- Wastewater is generated in homes, industries, agricultural fields, and 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 systems are breeding places 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.
Keywords
| Serial No. | Keywords | Serial No. | Keywords |
|---|---|---|---|
| 1 | Aeration | 7 | Sewage |
| 2 | Aerobic bacteria | 8 | Sewer |
| 3 | Anaerobic bacteria | 9 | Sewerage |
| 4 | Biogas | 10 | Sludge |
| 5 | Contaminant | 11 | Wastewater |
| 6 | Sanitation |
