Biological method of disposal of municipal solid waste refers to the process of using natural biological processes to break down and decompose organic waste materials. One such method is composting.

Composting is the process of decomposing organic waste materials, such as food scraps, yard waste, and paper products, under controlled conditions. This process is carried out by microorganisms, including bacteria, fungi, and other decomposers, which break down the organic matter into simpler compounds.

Below are the reasons why composting is considered a biological method of disposal of municipal solid waste:

1. Decomposition by microorganisms: Composting relies on the activity of microorganisms to break down organic waste. These microorganisms consume the organic matter and convert it into simpler compounds through metabolic processes. This natural biological process is essential in converting the waste into compost.

2. Aerobic conditions: Composting typically occurs under aerobic (oxygen-rich) conditions. Oxygen is necessary for the growth and activity of aerobic microorganisms, which are responsible for the breakdown of organic matter. These microorganisms require oxygen to carry out their metabolic processes, ensuring efficient decomposition of waste.

3. Temperature control: Composting involves maintaining the optimum temperature range for the growth and activity of microorganisms. The decomposition process generates heat as a byproduct, which helps raise the temperature within the compost pile. This elevated temperature promotes the activity of thermophilic microorganisms, which are more efficient in breaking down organic waste.

4. Nutrient recycling: Composting not only helps dispose of organic waste but also produces a nutrient-rich end product known as compost. Compost can be used as a natural fertilizer, returning essential nutrients to the soil and promoting plant growth. This nutrient recycling aspect of composting is beneficial for agricultural and horticultural purposes.

In summary, composting is a biological method of disposing of municipal solid waste as it relies on the natural activity of microorganisms to break down organic matter. Through controlled conditions, such as maintaining aerobic conditions and temperature, composting efficiently decomposes waste while producing a valuable end product in the form of compost.