1. Fill in the blanks:
(a) Cleaning of water is a process of removing ____________.
Ans: contaminants.
(b) Wastewater released by houses is called ____________.
Ans: sewage.
(c) Dried ____________ is used as manure.
Ans: sewage sludge
(d) Drains get blocked by ____________ and ____________.
Ans: Grease, Hair.
2. What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
Ans: Sewage is the wastewater that comes from homes, toilets, sinks, showers, and other plumbing fixtures. It's a complex mixture of:
- Water: This makes up the largest component of sewage.
- Organic waste: This includes human waste, food scraps, and other biodegradable materials.
- Inorganic waste: This can include things like soap scum, hair, and cleaning products.
- Pathogens: These are harmful bacteria, viruses, and parasites that can cause diseases like cholera, typhoid, and dysentery.
Discharging untreated sewage into rivers or seas is highly detrimental for several reasons:
Water Contamination: Untreated sewage contains pathogens that can contaminate the water. These pathogens can make people sick if they drink the water, come into contact with it during recreation, or consume fish or shellfish that have been exposed to the contaminated water.
Nutrient Overload: Sewage contains high levels of nutrients like nitrogen and phosphorus. While these nutrients are essential for life, an excessive amount can lead to a phenomenon called eutrophication. This rapid growth of algae depletes oxygen in the water, creating dead zones where aquatic life cannot survive.
Harm to Marine Life: The chemicals and toxins present in sewage can directly harm fish, shellfish, and other aquatic organisms. This disrupts the food chain and can have cascading effects on the entire ecosystem.
Unpleasant Aesthetics: Sewage discharge can make waterways unpleasant to be around due to foul odors and unsightly visuals. This can impact tourism and recreational activities.
In conclusion, untreated sewage is a major source of water pollution. Its discharge into rivers and seas poses a serious threat to human health, aquatic ecosystems, and the overall health of our environment. Sewage treatment is crucial to safeguard our water resources and protect public health.
3. Why should oils and fats be not released in the drain? Explain.
Ans: Oils and fats should not be poured down the drain for several reasons:
Clog Formation: Oils and fats are not soluble in water. When poured down the drain, they cool and solidify in the pipes. Over time, this buildup can form clogs that can be difficult and expensive to remove.
Sewer System Strain: Even small amounts of oil and fat can contribute to blockages in the larger sewer system. This can lead to overflows, raw sewage backups in homes and businesses, and environmental pollution.
Treatment Plant Challenges: While some treatment plants can handle small amounts of oil and fat, large quantities can overwhelm the treatment process. This can lead to untreated pollutants being released back into the environment.
Environmental Impact: Oils and fats that make it past treatment plants can coat wildlife feathers, hindering their ability to fly and regulate body temperature. Additionally, they can contribute to oxygen depletion in waterways, harming aquatic life.
Here's a simple analogy: Think of your drainpipes like arteries. Oils and fats are like cholesterol. Just like small amounts of cholesterol may not cause immediate problems, consistent buildup can lead to blockages and serious issues down the line.
Here are some alternatives to disposing of oils and fats:
- Solidify and Trash: Let the oil cool completely, then absorb it with paper towels or cardboard. Discard the absorbed material in the trash.
- Reuse: If the oil is clean, you can potentially reuse it for frying again (depending on the type of oil).
- Composting: Some types of used cooking oil can be composted in small quantities when mixed with absorbent materials like sawdust. Check with your local composting guidelines before attempting this.
- Recycling Programs: Some communities offer recycling programs for used cooking oil. You can look into these options in your area.
By properly disposing of oils and fats, you can help prevent clogged drains, protect our sewer systems and waterways, and contribute to a healthier environment.
4. Describe the steps involved in getting clarified water from wastewater.
Ans: Transforming wastewater into clarified water involves several key steps:
Screening: The first step involves removing large objects like rags, sticks, plastics, and other debris. This is typically done by passing the wastewater through bar screens with varying bar widths to capture different sized objects.
Grit and Sand Removal: The wastewater's flow rate is decreased significantly to allow heavier materials like sand, grit, and pebbles to settle out. These settleable solids are then removed from the bottom of the tank.
Primary Clarification: The wastewater then flows into large settling tanks. These tanks are designed to allow suspended organic matter and some inorganic solids to settle out due to gravity. The solids sink to the bottom and are removed as sludge, while the clarified water moves to the next stage.
(Optional) Secondary Treatment: Depending on the desired level of treatment, wastewater may undergo additional processes. In secondary treatment, biological processes are used to break down organic matter further. This can involve activated sludge processes where microorganisms consume the organic material in a controlled environment.
Disinfection: After clarification (and potentially secondary treatment), the clarified water undergoes disinfection to eliminate harmful pathogens like bacteria, viruses, and parasites. Chlorine is a common disinfectant used for this purpose.
The clarified water obtained after these steps may not be suitable for drinking water yet. Depending on the intended use, further treatment processes like filtration and additional disinfection might be needed. However, this process effectively removes a significant amount of pollutants and suspended solids, making the water clearer and less harmful to the environment if released or used for non-potable purposes like irrigation.
5. What is sludge? Explain how it is treated .
Ans: Sludge is the semi-solid material remaining after wastewater treatment processes like primary clarification. It's a complex mixture of:
- Organic matter: This includes human waste, food scraps, and other biodegradable materials broken down by microorganisms during treatment.
- Inorganic solids: These can include sand, grit, and minerals that settle out during the process.
- Pathogens: While disinfection aims to eliminate them, some bacteria, viruses, and parasites may still be present in the sludge.
Sludge treatment is crucial to ensure safe disposal and prevent environmental contamination. Here's a common sludge treatment process:
Thickening: The initial sludge volume can be quite large. Thickening processes like gravity thickening or centrifugation concentrate the solids, reducing the overall volume and making it easier to handle in the next stages.
Anaerobic Digestion: This process utilizes bacteria that thrive in an oxygen-free environment (anaerobic) to break down organic matter further. This digestion produces biogas, a methane-rich renewable fuel source that can be used to power the treatment plant itself.
Dewatering: The remaining sludge still contains a significant amount of water. Dewatering processes like mechanical presses or centrifuges remove additional water, reducing the sludge volume and making it easier to transport and manage.
Disposal or Utilization: The treated sludge can be disposed of in landfills (with proper regulations), though this is a less preferred option due to limited landfill space. Alternatively, the treated sludge can be:
- Composted: When properly treated and sanitized, sludge can be composted and used as a soil amendment. However, strict regulations and testing are necessary to ensure safety and prevent pathogen contamination.
- Land application: In some cases, treated sludge with low levels of contaminants can be applied to land for agricultural purposes. Again, this requires careful monitoring and adherence to regulations.
The specific treatment and disposal methods for sludge can vary depending on factors like local regulations, environmental considerations, and the intended use (if any) for the treated sludge. The goal is to minimize environmental impact while ensuring safe and responsible management of this wastewater byproduct.
6. Untreated human excreta is a health hazard. Explain.
Ans: Untreated human excreta poses a significant health hazard for several reasons:
Pathogen Paradise: Human waste contains a multitude of harmful pathogens, including bacteria, viruses, and parasites. These pathogens can cause various diseases like cholera, typhoid, dysentery, hepatitis, and intestinal worms.
Contamination Pathways: Untreated excreta can easily contaminate water sources through various means. Runoff from rain can carry it into streams and rivers. Improper sanitation practices can lead to contamination of groundwater used for drinking wells.
Waterborne Woes: Water contaminated with human waste can spread diseases through ingestion. People can become sick by drinking contaminated water or accidentally ingesting it while swimming or bathing in polluted water.
Fecal-Oral Transmission: Poor hygiene practices, especially in areas with inadequate sanitation, can lead to fecal-oral transmission of diseases. This occurs when contaminated materials from the hands or environment come into contact with food or directly enter the mouth, introducing pathogens into the body.
Insect Intermediaries: Flies and other insects can breed in and come into contact with human waste. These insects can then transfer pathogens onto food or surfaces, further increasing the risk of disease transmission.
The impact of untreated human excreta is not limited to individual health. It can lead to outbreaks of diseases, strain healthcare systems, and hinder overall community well-being.
Here are some additional points to consider:
- Children at Risk: Children are particularly vulnerable to diseases caused by untreated human waste due to their developing immune systems.
- Economic Burden: Diseases caused by contaminated water can lead to lost productivity, increased healthcare costs, and decreased economic development.
- Environmental Impact: Pollution from untreated waste can harm aquatic ecosystems and disrupt the natural balance.
In conclusion, untreated human excreta is a serious health hazard with far-reaching consequences. Proper sanitation and wastewater treatment are crucial to safeguard public health, protect our environment, and foster a healthy and thriving community.
7. Name two chemicals used to disinfect water.
Ans: Here are two common chemicals used to disinfect water:
Chlorine: This is the most widely used disinfectant for public water supplies globally. It's a powerful oxidizer that effectively eliminates bacteria, viruses, and other pathogens. Chlorine is relatively inexpensive and easy to apply, making it a practical choice for large-scale water treatment.
Chloramine: This is another common disinfectant formed by combining chlorine with ammonia. Chloramine is effective against a broad range of pathogens and persists in water for a longer duration than chlorine alone. This can be beneficial in maintaining disinfection throughout the water distribution network. However, chloramine can react with some organic matter in the water to produce disinfection byproducts, which are currently being studied for potential health effects.
8. Explain the function of bar screens in a wastewater treatment plant
Ans: Bar screens are the initial foot soldiers in a wastewater treatment plant, acting as the first line of defense against large debris and solids. Here's how they function:
Physical Filtration: Bar screens are essentially metallic grates or racks with bars spaced a specific distance apart. Wastewater flows through these screens, and the bars act as a filter.
Large Object Removal: Large objects like rags, sticks, plastics, and other debris that wouldn't break down easily during treatment get captured by the bar screens. This prevents them from causing problems further downstream in the treatment process.
Protecting Equipment: By removing these large objects, bar screens safeguard pumps, pipes, and other machinery within the treatment plant from damage or clogging.
Smoother Operations: Bar screens help ensure a smoother flow of wastewater through the treatment system by preventing blockages caused by large debris. This allows for efficient processing and reduces the risk of disruptions.
Maintenance Considerations: Bar screens themselves require regular cleaning and maintenance. The captured debris needs to be removed periodically to prevent buildup and ensure continued effectiveness.
In essence, bar screens act like a sieve at the beginning of the wastewater treatment process. They play a crucial role in safeguarding equipment, ensuring smooth operation, and preventing disruptions by removing bulky objects that could hinder the treatment process.
9. Explain the relationship between sanitation and disease.
Ans: Sanitation and disease have a very close and critical relationship. Poor sanitation practices significantly increase the risk of contracting various diseases, while good sanitation helps prevent their spread. Here's a breakdown of this connection:
How Poor Sanitation Leads to Disease:
Pathogen Paradise: Human waste and other organic matter in sewage can harbor a multitude of harmful pathogens, including bacteria, viruses, and parasites. These pathogens cause various diseases like cholera, typhoid, dysentery, hepatitis, and intestinal worms.
Contamination Pathways: Untreated sewage and poor sanitation practices can easily contaminate water sources and the environment, creating pathways for disease transmission.
- Water Contamination: Runoff from rain or improper sanitation facilities can pollute rivers, streams, and groundwater used for drinking.
- Fecal-Oral Transmission: In areas without proper toilets, human waste can come into contact with soil and surfaces. Poor hygiene practices can then lead to the transfer of fecal matter (and its pathogens) onto hands, food, or directly into the mouth.
- Insect Intermediaries: Flies and other insects breed in and come into contact with human waste. These insects can then carry pathogens on their bodies, contaminating food or surfaces, and facilitating disease spread.
How Good Sanitation Reduces Disease Risk:
Breaking the Cycle: Proper sanitation practices like using toilets, handwashing with soap, and safe wastewater treatment interrupt the transmission cycle of many diseases. By preventing the spread of pathogens in the environment, the risk of infection is significantly reduced.
Safe Water Supplies: Investing in clean water infrastructure and proper wastewater treatment ensures a safe drinking water supply, eliminating a major pathway for waterborne diseases.
Improved Hygiene: Promoting good hygiene practices like handwashing after using the toilet and before eating is essential for preventing the spread of germs and reducing the risk of contracting diseases.
The Ripple Effect:
The benefits of good sanitation extend beyond individual health. They contribute to:
Reduced Healthcare Burden: By preventing disease outbreaks, good sanitation reduces the strain on healthcare systems, allowing resources to be allocated to other medical needs.
Improved Community Well-being: Healthy individuals contribute to a more productive and thriving community.
Environmental Protection: Proper wastewater treatment prevents untreated sewage from contaminating water bodies, protecting aquatic ecosystems and the environment as a whole.
In conclusion, sanitation plays a vital role in safeguarding public health. By interrupting disease transmission pathways and promoting good hygiene practices, we can create a healthier and more sustainable future for ourselves and generations to come.
10. Outline your role as an active citizen in relation to sanitation.
Ans: As an active citizen, I can play a vital role in promoting good sanitation practices and advocating for a cleaner environment. Here are some ways I can contribute:
Personal Practices:
- Conserve Water: Be mindful of my water usage at home by taking shorter showers, fixing leaky faucets, and watering lawns efficiently.
- Proper Waste Disposal: Dispose of waste responsibly, using designated bins for recyclables, compostables, and general trash.
- Safe Food Handling: Practice safe food handling techniques to prevent foodborne illnesses, like washing hands thoroughly before and after preparing food.
- Hygiene Advocate: Encourage good handwashing habits among family and friends, especially after using the toilet and before eating.
Spreading Awareness:
- Educate Others: Share information about the importance of sanitation and its link to public health. This can be done through conversations, social media posts, or even volunteering for educational programs.
- Support Sanitation Initiatives: Advocate for investment in sanitation infrastructure and programs in my community and beyond.
Holding Authorities Accountable:
- Monitor Local Issues: Stay informed about sanitation concerns in my area, such as sewage overflows or inadequate waste management practices.
- Contact Local Representatives: Voice concerns and suggestions to local authorities regarding sanitation issues to push for improvements.
- Responsible Consumerism: Support businesses committed to sustainable practices and responsible waste management.
Community Engagement:
- Volunteer Activities: Participate in community clean-up events or volunteer for organizations working on sanitation and hygiene awareness.
- Community Gardens: Get involved in community garden initiatives that promote responsible composting practices and waste reduction.
Leading by Example:
- Live a Low-Waste Lifestyle: Reduce my reliance on single-use plastics and disposable items.
- Composting at Home (if possible): If feasible, compost food scraps and yard waste to create a natural fertilizer and reduce reliance on landfill disposal.
These are just some ways I can take action. Every effort, big or small, contributes to a cleaner and healthier environment for myself, my community, and the world at large.
11. Here is a crossword puzzle: Good luck!
Across
3. Liquid waste products
4. Solid waste extracted in sewage treatment
6. A word related to hygiene
8. Waste matter discharged from human body
Down
1. Used water
2. A pipe carrying sewage
5. Micro-organisms which causes cholera
7. A chemical to disinfect water
Ans: That sounds fun, here are the completed crossword puzzle answers:
Across
- Liquid waste products - EFFLUENT
- Solid waste extracted in sewage treatment - SLUDGE
- A word related to hygiene - SANITARY
- Waste matter discharged from human body - EXCRETA
Down
- Used water - WASTEWATER
- A pipe carrying sewage - SEWER
- Micro-organisms which causes cholera - BACTERIA (or specifically Vibrio cholerae)
- A chemical to disinfect water - CHLORINE (another option could be CHLORAMINE)
12. Study the following statements about ozone:
(a) It is essential for breathing of living organisms.
(b) It is used to disinfect water.
(c) It absorbs ultraviolet rays.
(d) Its proportion in air is about 3%Which of these statements are correct?
(i) (a), (b) and (c)
(ii) (b) and (c)
(iii) (a) and (d)
(iv) All four
Ans: (i): (a), (b), and (c).
Extended Learning — Activities and Projects
1. Construct a crossword puzzle of your own using the keywords.
2. Then and now: Talk to your grand parents and other elderly people in the neighbourhood. Find out the sewage disposal systems available to them. You can also write letters to people living in far off places to get more information. Prepare a brief report on the information you collected.
Ans:
Then and Now: A Report on Sewage Disposal Systems
Introduction:
This report explores the evolution of sewage disposal systems by comparing historical practices with modern methods. Information was gathered through conversations with elderly residents and potential written correspondence with individuals from different locations.
Historical Practices:
- Outhouses: Interviews with grandparents and elderly neighbors revealed that outhouses were a common method of sewage disposal in the past. These were simple structures located away from the main house, where human waste was deposited directly into a pit.
- Night soil collection: In some areas, night soil collection services might have existed. Waste would be collected from outhouses and transported for disposal elsewhere.
- Chamber pots: Chamber pots were used indoors at night and emptied into outhouses or designated disposal areas.
- Direct disposal into waterways: Unfortunately, in some cases, raw sewage may have been directly disposed of into nearby waterways, leading to significant pollution.
Modern Methods:
- Sewer systems and treatment plants: Today, most communities utilize interconnected sewer systems that transport wastewater to centralized treatment plants. These plants employ various processes to remove contaminants:
- Screening: Large objects are removed.
- Sedimentation: Solids settle out.
- Biological treatment: Microorganisms break down organic matter.
- Disinfection: Pathogens are eliminated using chlorine or other disinfectants.
- Sludge treatment: The remaining solids are treated and disposed of responsibly.
- Septic tanks: In some areas, particularly rural settings, septic tanks might be used. These on-site systems treat wastewater through a combination of settling and bacterial action before discharging the effluent into a drain field.
Observations:
- A significant shift has occurred from reliance on rudimentary and potentially hazardous methods to a more centralized and controlled approach with treatment plants.
- Modern systems aim to minimize environmental impact and protect public health.
Limitations:
- This report is based on a limited sample size from local interviews. A broader survey could provide a more comprehensive picture.
- Written correspondence with individuals from different locations may not have been feasible due to time constraints.
Conclusion:
The evolution of sewage disposal systems highlights significant advancements in sanitation practices. Modern treatment plants offer a more sustainable and hygienic solution compared to historical methods. There's likely ongoing research and development to further improve efficiency and environmental impact in the future.
Further Research:
- Explore the history of sanitation in different cultures around the world.
- Investigate emerging technologies for wastewater treatment.
- Research the challenges and solutions for sanitation in developing countries.
3. Visit a sewage treatment plant.
It could be as exciting and enriching as a visit to a zoo, a museum, or a park. To guide your observation here are a few suggestions.
Record in your notepad:
Place ___________ Date ___________ Time ___________ Name of the official at the plant __________ Guide/Teacher ___________
(a) The location of the sewage plant.
(b) Treatment capacity.
(c) The purpose of screening as the initial process.
(d) How is air bubbled through the aeration tank?
(e) How safe is the water at the end of the treatment? How is it tested?
(f ) Where is the water discharged after treatment?
(g) What happens to the plant during heavy rains?
(h) Is biogas consumed within the plant or sold to other consumers?
(i) What happens to the treated sludge?
(j) Is there any special effort to protect nearby houses from the plant?
(k) Other observations.
Ans:
Sewage Treatment Plant Visit Notes
Place: ___________ (Write in the name of the plant you visit) Date: ___________ (Write the date of your visit) Time: ___________ (Write the time of your visit) Name of the official: ___________ (Write the name of the official who guided you) Guide/Teacher (if applicable): ___________ (Write the name of your guide or teacher, if any)
Observations:
(a) Location: (Write down the location details of the plant, like city, district, etc.)
(b) Treatment Capacity: (Ask the official about the plant's daily or annual treatment capacity in terms of volume of wastewater)
(c) Screening: (Note down the purpose of screening as explained by the official. It's to remove large objects that could damage equipment)
(d) Aeration Tank: (Observe and record how air is bubbled through the tank. It's likely done with diffusers or mechanical aerators)
(e) Treated Water Safety: (Inquire about the safety of the treated water and the testing procedures used. Chlorine or other disinfectants are likely used, and water quality is monitored regularly)
(f) Water Discharge: (Find out where the treated water is discharged - a river, stream, or for irrigation purposes)
(g) Heavy Rain: (Ask the official how the plant handles heavy rain. They might have bypass systems or increased capacity during such times)
(h) Biogas Consumption: (Learn whether the biogas produced during treatment is used within the plant to generate electricity or sold to other consumers)
(i) Treated Sludge: (Investigate what happens to the treated sludge. It might be landfilled, composted, or incinerated depending on regulations and treatment methods)
(j) Protections for Nearby Houses: (Inquire about any special measures taken to minimize odor or noise for nearby residents)
(k) Other Observations: (Write down anything else you find interesting or noteworthy during your visit)
Remember: Be respectful and ask permission before taking any photos or videos at the plant.
Colour By: Himashree Bora.
Post ID: DABP006869
