Wastes that are capable of being broken down or decomposed rapidly by the actions of microorganisms are called as biodegradable wastes. Fruit-peels, cake, lime juice, wood and grass can be easily decomposed by the microbes. 

DDT, plastics, broken glasses are example of non-biodegradable wastes

The methods of disposal of kitchen waste include Composting as well as landfilling. Composting is a process in which organic matter like compost is decomposed. It is done with the help of certain micro-organisms which can utilize these organic substances and convert it into simpler substances. And landfilling is a process in which the compost is buried inside the land so that the gases produced by the rotten food and other organic material is disposed of. This also increases the nutritional value of the soil.

Milk tin would take years to decompose as it is made up of metals. Decomposition of metals takes longer time as compared to pizza box- cardboard, apple peel and tissue paper.

Landfill is a highly engineered facility to ensure the safe removal of waste from the society. The modern landfills not only can serve as reclaimed land which can be converted into parks and playgrounds, they also serve in other purposes like methane production (landfill gas) etc.