Problem 47 - A Complete Resource Book in Chemistry for JEE Main

Question

Proper management for disposal of household and industrial wastes can be done by (a) sewage treatment (b) recycling the waste material to give useful products again (c) burning and incineration of combustible waste (d) all of these

Step-by-Step Solution

Answer

(d) all of these

Step 1: Understanding the Question

The question is asking about proper management methods for the disposal of both household and industrial wastes. It provides some possible answers and asks which of them is a correct method or if all are applicable.

Step 2: Analyzing Option (a)

Option (a) states 'sewage treatment,' which is a process used to treat wastewater from households and industries to remove contaminants and make it safe for disposal or use. This is a valid waste management strategy.

Step 3: Examining Option (b)

Option (b) involves 'recycling the waste material to give useful products again.' Recycling reduces waste, conserves natural resources, and is a widely recognized method for managing waste effectively.

Step 4: Checking Option (c)

Option (c) discusses 'burning and incineration of combustible waste.' This method reduces the volume of waste by converting it to ash, heat, and steam through incineration. While it has environmental concerns, it is still considered a waste management method.

Step 5: Evaluating Option (d)

Option (d) suggests 'all of these,' indicating that all the methods listed (sewage treatment, recycling, and incineration) are considered proper management practices. Since each of the previous options are viable individually, it's logical that all together provide a comprehensive approach.

Key Concepts

Sewage Treatment

Sewage treatment is a vital process in waste management. It involves the removal of harmful substances from wastewater, making it safe for release back into the environment or reuse. The process typically starts with the collection of wastewater from households and industrial sources. This water contains contaminants like organic matter, bacteria, and toxic substances.

Once collected, the sewage passes through several treatment stages. These include:

• Preliminary Treatment: This is the initial stage where screens and grates remove large debris and solids.
• Primary Treatment: Here, the water is held in large settling tanks where solids can settle to the bottom. Any oils and grease float to the top for removal.
• Secondary Treatment: This process involves using bacteria to break down organic matter. This stage significantly reduces the amount of bacteria and organic waste.
• Tertiary Treatment (if necessary): This advanced treatment stage might involve further filtration or chemical treatment to remove any remaining contaminants.

Sewage treatment is essential for protecting water resources and public health. It ensures that the water released into the environment is clean and minimizes the risk of waterborne diseases.

Recycling

Recycling is an effective and sustainable method for waste management. It involves collecting and processing materials to create new products instead of using new raw materials. Recycling helps reduce the amount of waste sent to landfills and conserves natural resources like timber, water, and minerals.

The recycling process typically involves three main steps:

• Collection and Sorting: Recyclables are gathered from homes, businesses, and recycling centers. These materials are then sorted into categories such as paper, plastics, glass, and metals.
• Processing and Manufacturing: Once sorted, materials are processed into raw forms. For example, plastic is melted down into pellets or paper is pulped to be reformed into new sheets.
• Creating New Products: Recycled raw materials are used in manufacturing to create new consumer goods, packaging, and other products.

Recycling not only decreases pollution and energy consumption but also promotes a circular economy where resources are continually reused. This helps sustain the environment for future generations.

Incineration

Incineration is another method of waste management involving the burning of waste materials at high temperatures. This process reduces the volume of waste by converting it into ash, flue gas, and heat, which can be used for energy generation.

There are several types of incineration practices:

• Mass Burn: This is the most common method, where mixed waste is burned without prior sorting.
• Refuse-Derived Fuel (RDF): Waste is treated, and non-combustible items are removed before incineration. This produces a fuel that can generate energy.
• Fluidized Bed: This advanced method involves suspending waste on gas for more efficient combustion, often improving energy recovery.

While incineration significantly reduces waste volume, it does have drawbacks, such as air pollution and greenhouse gas emissions. Therefore, incineration plants often incorporate pollution control technologies to mitigate environmental impact. Used responsibly, incineration can be a valuable component in a comprehensive waste management strategy.