In municipal solid waste management, which of the following techniques is generally regarded as the least preferred option for disposal of solid waste, to be used only when reuse, recycling, and composting are not feasible?

Introduction / Context:
Municipal solid waste management follows a waste hierarchy that prioritises certain methods over others based on environmental impact and resource efficiency. At the top are waste reduction, reuse and recycling, followed by energy recovery, and finally disposal options for what remains. Understanding which techniques are considered least desirable helps planners and citizens make better decisions about how to handle solid waste. This question asks you to identify which listed method is generally treated as the last resort in modern solid waste management strategies.

Given Data / Assumptions:

• We are dealing with municipal solid waste, which includes household, commercial and some institutional waste.
• Preferred approaches include material recovery, composting and energy recovery, which reduce the amount of waste that needs to be disposed of.
• Land filling involves burying waste in dedicated landfill sites.
• Incineration can be used with energy recovery under controlled conditions.
• Briquetting compacts combustible fractions of waste into fuel briquettes.

Concept / Approach:
The waste management hierarchy ranks options from most to least preferred as follows: reduce, reuse, recycle, recover energy and finally dispose. Land filling of mixed municipal solid waste is usually considered the least preferred option because it occupies large areas of land, can lead to long term pollution of soil and groundwater through leachate, and generates methane, a powerful greenhouse gas. While controlled incineration with energy recovery and briquetting both fall under energy recovery, and composting recycles organic matter into useful soil conditioner, land filling mainly buries the problem and uses land resources. Therefore, when choosing among the listed options, land filling stands out as the last resort that should be minimised as far as possible.

Step-by-Step Solution:
Step 1: Recall the general waste hierarchy: first reduce, then reuse, then recycle, then recover energy, and finally dispose of what remains in landfills. Step 2: Examine composting, which converts biodegradable waste into useful compost that can replenish soil nutrients and is therefore a preferred recycling method. Step 3: Consider incineration with proper pollution control and energy recovery, which reduces waste volume and generates electricity or heat, placing it above simple disposal in the hierarchy. Step 4: Recognise that briquetting converts combustible fractions of waste into fuel briquettes, another energy recovery strategy that reduces the volume of waste requiring final disposal. Step 5: Compare these with land filling of mixed solid waste, which simply stores waste in the ground and often creates long term environmental risks. This process is normally treated as the least preferred disposal method, so land filling of mixed solid waste is the correct answer.

Verification / Alternative check:
Municipal solid waste management guidelines and environmental policies from various countries emphasise the goal of reducing the amount of waste sent to landfills. They highlight the problems of limited land availability, long term monitoring needs, leachate control and greenhouse gas emissions from landfills. In contrast, composting and recycling are promoted actively, and energy recovery technologies are considered acceptable intermediate options when done with proper environmental controls. The repeated description of land filling as a last resort confirms that it is the least preferred technique among the options given in the question.

Why Other Options Are Wrong:
Option a, incineration, when properly controlled and combined with energy recovery, is considered somewhat more acceptable than simply burying waste, although it still has environmental challenges.

Option b, composting, is a very desirable method for biodegradable waste, as it returns nutrients to the soil and reduces landfill load.

Option d, briquetting, helps to recover energy from combustible waste and reduces the volume of waste requiring final disposal, making it more preferable than directly land filling mixed waste.

Common Pitfalls:
Some learners may assume that incineration is always the worst method because of the possibility of air pollution, but modern solid waste management considers both air and land impacts. Others may ignore the stated context of the waste hierarchy and choose composting or briquetting incorrectly. The key is to remember that landfills, although currently necessary in many cities, are seen as the least preferred option and are targeted for reduction by policies that encourage recycling, composting and energy recovery first.

Final Answer:
The least preferred technique for municipal solid waste disposal among the options given is Land filling of mixed solid waste.