Waste water Story - CBSE Notes
1. Waste water and Sewage
➥Wastewater: It is the water that has been used in homes, industries, or other activities and contains harmful substances. Examples include water from kitchens, bathrooms, and industries.
➥ Sewage: A type of wastewater that includes domestic and industrial waste carried away by sewers. It consists of both liquid and solid waste.
2. Components of Sewage
- Contaminants: These are unwanted substances that make water impure and harmful for use.
- Organic Impurities: These include food waste, human and animal excreta, and plant debris. They decompose naturally but cause pollution if untreated.
- Inorganic Impurities: Chemicals, salts, and metals like nitrates, phosphates, and heavy metals present in wastewater.
- Suspended Particles: Solid particles such as paper, plastic, and silt that do not dissolve in water.
3. Effects of Sewage Discharged in Water Bodies
➥ The direct release of untreated sewage into water bodies leads to several adverse effects:
- Decreases oxygen levels in water, affecting aquatic life.
- Promotes the growth of harmful microorganisms, leading to diseases like cholera and typhoid.
- Causes foul odor and degradation of the ecosystem.
4. Wastewater Treatment Plant (WWTP)
➥ A wastewater treatment plant (WWTP) processes sewage to remove contaminants before releasing it into the environment. It involves several stages:
- Sewage System: A network of pipes, called Sewers, collects sewage and directs it to treatment plants. Access points like Manholes allow maintenance.
- Primary Treatment: Large particles and grit are removed through sedimentation and screening.
- Secondary Treatment: Biological treatment uses bacteria to break down organic matter in an Aeration Tank. The resulting sludge is called Activated Sludge.
- Sludge Digester: Sludge is treated in digesters to produce biogas, which can be used as a fuel.
- Tertiary Treatment: Advanced processes remove remaining pollutants, making water safe for release or reuse.
5. Sanitation and Hygiene
➥ Sanitation: It refers to measures taken to ensure cleanliness and proper disposal of human and other waste to prevent diseases.
➥ Hygiene: Practices like washing hands, maintaining clean surroundings, and using clean water for daily activities to promote health.
6. Reusing Wastewater
➥ Treated wastewater can be reused in various ways:
- Agriculture: Irrigation of fields.
- Industry: Cooling and processing water.
- Groundwater Recharge: Injecting treated water into aquifers.
7. Sanitation in Rural Areas
➥ In rural areas, sanitation involves:
- Constructing toilets to reduce open defecation.
- Proper waste disposal systems.
- Awareness programs about hygiene and disease prevention.
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