Disposal of waste - class-VIII

In solid waste management, the two primary methods of collection are typically categorized as house-to-house collection and community bin collection.

Solid waste management encompasses the entire process of collecting, treating, and disposing of waste. Among the choices, disposal is the most comprehensive term for the final management stage.

Incineration has a relatively high initial cost because it requires specialized high-temperature furnaces, pollution control systems, and ongoing maintenance. Landfilling and composting are generally less capital-intensive options.

Combustible materials, including rubbish and animal remains, are typically incinerated (burnt) to reduce volume and eliminate pathogens. While they can be landfilled, burning is the standard management practice for combustible waste.

Composting is most suitable for Indian conditions because it's low-cost, environmentally friendly, and produces useful fertilizer. India's climate supports rapid aerobic composting, and it handles the high organic content in Indian waste.

Polyblend is a fine powder of recycled modified plastic. The binding property of plastic makes the road last longer besides giving strength to withstand more loads when mixed with bitumen. Polyblend lowers moisture absorption capacity due to the coating of plastics at the surface.

The burning of a substance at high temperature to form ash is called incineration. It is used to destroy biological waste. All the organic matter present in the waste is removed as carbon dioxide and water vapour.

Composting is considered the most hygienic solid waste disposal method because it converts organic waste into stable, pathogen-free compost through controlled microbial decomposition. It's environmentally friendly and produces useful fertilizer.

Scientific estimates of the total solid matter transported by rivers into the oceans are generally cited around 300 million tonnes annually. This is a specific factual figure often found in environmental science textbooks.

Scrubbers are air pollution control devices used to remove harmful gases and particulate matter (dust) from industrial exhaust streams. They work by spraying a liquid to capture the pollutants.

Organic waste, sewage, and manure are rich in nutrients and organic matter, which improve soil structure and fertility. Therefore, their application increases, rather than decreases, the fertility of degraded lands.

Sanitary landfilling is cheaper and simpler than incineration or specialized recycling. It involves compacting waste in lined pits and covering with soil daily, requiring minimal infrastructure compared to other methods.

All listed practices, including using cloth bags, conserving electricity, and utilizing public transport, reduce resource consumption and environmental impact. They are all recognized as environmentally friendly.

When land is scarce or dumping areas are unavailable, incineration is the preferred method because it significantly reduces the volume of waste. This makes it ideal for urban areas with limited space.

The scientific method of solid waste management where the waste is heated to high temperature. This process is beneficial for obtaining gas and electricity. The method is suitable for municipal solid waste management.

Approximately 3300 million tonnes of solid matter from land is washed annually into oceans. Apart from the soil, glasses, metals and plastics are also washed into oceans. This matter spreads over the sea floor.

Modern materials science has led to the substitution of traditional metals like steel and copper with plastics, ceramics, and high-strength glass fibers in various industrial applications due to their specific properties.

Landfilling is often unsuccessful in India due to the lack of properly engineered sanitary landfills, leading to open dumping, leachate issues, and environmental contamination. Other methods like composting have seen more localized success.

Landfilling is generally the most simple and economical method for solid waste disposal, especially when land is available. It requires minimal processing compared to incineration or pyrolysis.

Over time, the organic components in landfilled solid waste undergo biological decomposition by microorganisms, which leads to the stabilization of the waste mass.