Difference Between Decomposition and Combustion

Decomposition vs Combustion
 

Both decomposition and combustion are chemical processes of converting complex material into much simpler compounds.

Decomposition

Decomposition is a natural process. When animals and plants die and excrete, their bodies and other waste material are broken down into smaller pieces and ultimately to simpler forms of matter. This process is known as decomposition. If not for this process, all the dead bodies will be stocked up on the earth surface, and there won’t be space for new organisms. Therefore, decomposition is important to recycle the matter to clear space in the biome. In an ecosystem, invertebrates like earthworm, bacteria and fungi are responsible for decomposing material. They perform an important role in a food chain, by providing nutrients for plants by decomposing. Meanwhile, decomposers take food for them by extracting chemicals from the dead bodies and use these to produce energy. When decomposers die and excrete, these materials also decompose. Therefore, this is a cycle of nutrient flow within the ecosystems. Decomposition of an organism begins soon after death, and it undergoes a sequence of stages, which is common to any organisms. This process has five stages as fresh, bloat, active decay, advanced decay, and dry/remains stage. Fresh stage is the stage just after the death of the organism. The normal activities have stopped, and the body gradually becomes cold. Since the oxygen presented in the body is quickly depleting, the anaerobic organisms are starting to grow rapidly in the body. In bloat stage, the anaerobic organism activity is very high. Therefore, the gases produced by their processes tend to accumulate in the dead body and gives a bloated appearance. In the active decay stage, the body mass is lost rapidly. By the advanced decay stage, the decaying activity has largely inhibited. And in the final stage only bones, cartilages and skin is remaining. High levels of nutrients will be present in the surrounding soil at the dry/ remains stage.

There are many factors, which contribute to the rate of decomposition. For example, material exposed to water and air will decompose faster than a material without water and air. Temperature, oxygen level, water, access by scavengers, and body sizes are some of the factors that determine the rate of decomposition.

Combustion

Combustion is an exothermic chemical reaction, which produces heat by the reaction between a fuel and an oxidant. In this process, the starting material will be converted to other forms of compounds, while producing heat. Fuels can be hydrocarbons in the solid, liquid or gaseous form. Most commonly the oxidant is oxygen gas. In the hydrocarbon combustion, carbon dioxide and water are produced as main products. Often when the oxidant is oxygen, the products are oxides of different elements present in the fuel. Combustion reactions are used to generate energy in vehicle engines and machines, for cooking purposes, etc. Combustion can be of two types as complete and incomplete combustion. Incomplete combustion occurs when there isn’t enough oxygen. This will produce various types of by-products and particulate matter, which cause environmental pollution. Incomplete combustion, only a limited number of products will be produced.