CG Board Class 9 Science Chapter 18 Solutions: Waste and its Management (कचरा और उसका प्रबंधन) – 2026-27

Imagine what would happen if the amount of waste generated daily accumulates at a place?

If daily generated waste accumulates at one place without proper disposal, it creates huge dumps. These piles emit foul odors, block drain pipes, pollute surrounding land and air, and become breeding grounds for disease-causing organisms like mosquitoes, flies, and rats.

What are the different problems that would arise out of this waste accumulation?

The main problems arising from waste accumulation are:

1. Disease Outbreaks: Unhygienic conditions lead to rapid multiplication of vectors like rats, flies, and mosquitoes, spreading epidemics like plague, malaria, and cholera.
2. Environmental Pollution: Rotting waste pollutes soil, releases foul gases into the air, and contaminates groundwater through leachate seepage.
3. Drainage Blockage: Plastic and floating waste choke urban drains, causing waterlogging during rains.

How would we resolve problems arising out of this waste or do away with the waste itself?

We can resolve waste problems by implementing proper segregation at source into wet (biodegradable) and dry (non-biodegradable) wastes. Biodegradable waste should be converted into organic manure or biogas, while dry recyclable items like plastics, glass, and metals should be sent to recycling units. Practicing the 4 R’s (Reduce, Refuse, Reuse, Recycle) reduces the overall waste burden.

Do kitchen wastes like vegetable/fruit peels or leftover food remain as such for a long period of time?

No, these organic materials do not remain as such for a long time. Microorganisms like bacteria and fungi act upon complex organic molecules and break them down into simple inorganic substances through the process of decomposition (rotting).

What happens to non-biodegradable wastes like plastic, metals, glass, and electronic devices?

Non-biodegradable wastes cannot be decomposed or broken down by microorganisms even if left in nature for hundreds of years. If dumped openly, they accumulate in landfills, pollute soil and groundwater, and choke drainage systems. Hence, they must be collected separately and sent to recycling industries.

What happens to wastes generated from commercial organizations (industries, hospitals, offices) and what do waste collectors do with collected household waste?

• Waste collectors sell sorted dry materials (paper, plastics, metals) to recycling dealers and dump the rest at municipal collection points.
• Hazardous waste from hospitals and factories is subjected to specialized medical incineration or industrial chemical treatment before safe disposal at designated municipal dumping grounds.

Can all wastes generated at home be converted to compost? Why or why not?

No, all household waste cannot be converted into compost. Only biodegradable wastes (vegetable peels, leftover food, fallen leaves, paper) can be converted into compost because microorganisms and earthworms can break them down. Non-biodegradable materials (plastic, glass, metals, polythene) cannot be decomposed by biological activity.

Among the mentioned efforts (Surat Municipal model, Domloor Town Women Campaign, Srinivas Vellore model), which one did you like most and why?

The model developed by Srinivas from Vellore district (Tamil Nadu) is the most inspiring. He categorized waste into 18 to 20 detailed sub-categories, fed edible waste to domestic animals, produced gobar gas fuel and rich vermicompost, utilized fish/ducks in ponds to keep water clean, ground eggshells/bones for fertilizer, and generated local rural employment.

What can you do to manage waste in your locality based on the given examples?

Based on these initiatives, we can take the following local steps:

1. Start a door-to-door awareness drive asking residents to segregate wet and dry waste at household level.
2. Setup a community composting or vermicomposting pit for biodegradable kitchen waste.
3. Send collected recyclable dry wastes (paper, plastic, metals) directly to recycling units.
4. Discourage single-use plastics and encourage cloth/jute bags.

Can we make an attempt to reduce the production of waste?

Yes, waste production can be significantly reduced at its source by adopting the 4 R’s:

• Reduce: Minimize unnecessary consumption (e.g., write on both sides of notebook pages).
• Refuse: Say no to single-use plastics and polythene bags.
• Reuse: Use durable containers, bottles, and cloth bags repeatedly.
• Recycle: Send materials like paper, glass, and metals to recycling processing plants.

(i) Which is the best level of sorting out wastes among the following?**

(ii) Which substances can be decomposed easily using microorganisms?

(iii) Organism helpful for composting is:

Any discarded, unused, unwanted, or rejected material produced from domestic, agricultural, commercial, or industrial human activities that is no longer useful to the owner at that time is defined as waste.

Decomposition** is a natural biological process in which decomposers like bacteria, fungi, and earthworms break down complex organic matter (vegetable peels, dead plant leaves, animal remains) into simple inorganic nutrients like carbon dioxide, water, nitrogen, phosphorus, and potassium. These simple nutrients enrich the soil, making it fertile for plant growth.

Sorting waste at source (at homes or shops) prevents biodegradable wet waste from getting mixed with dry recyclable items like paper, metals, and glass. Mixed waste gets contaminated, attracts pathogens, generates bad odor, and makes recycling extremely difficult and unhygienic. Sorting at source enables direct composting of wet waste and clean processing of dry materials.

1. Epidemics and Health Hazards: Accumulating waste breeds disease vectors like rats, flies, and mosquitoes, spreading epidemics like plague, malaria, and dengue.
2. Soil and Groundwater Contamination: Toxic chemical leachates from rotting waste seep into the ground, polluting groundwater reserves and reducing soil fertility.
3. Foul Odor and Air Pollution: Rotting organic waste emits highly toxic and foul-smelling gases, degrading ambient air quality.

The industrial or manual process of collecting discarded waste materials (like paper, plastic, glass, metal) and processing them to produce new raw materials or products is called recycling.

To prepare compost (or vermicompost), the following materials are required:

1. Biodegradable Kitchen/Farm Waste: Vegetable and fruit peels, leftover food, fallen dry leaves, chopped grass.
2. Animal Dung & Layering Material: Cow dung, topsoil layer.
3. Biological Agent: Earthworms (for vermicomposting).
4. Moisture & Cover: Water and wet gunny bags/sacks to maintain moisture.

From Srinivas’s innovative waste management model in Vellore, we learn:

1. Detailed Categorization: Waste can be sorted into 18 to 20 sub-categories for maximum recovery.
2. Resource Recovery: Recyclables (paper, plastic, glass, metal) should be sold directly to buyers.
3. Integrated Biological Utilization: Edible organic waste can feed domestic animals, dung produces gobar gas fuel and manure, and unabsorbed organic residue forms vermicompost.
4. Ecological Pest & Water Management: Using biological predators (hens, ducks, frogs) prevents pest breeding, while wastewater purified in fish ponds can be reused for irrigation.
5. Value Addition: Turning waste eggshells/bones into fertilizer, and dung ash with lemon peels into cleaning soap.