What is Composting? Types and Benefits of a Compost

Table of Contents

What is Compost?

Compost of organic material
Compost of organic material

Compost can be defined as a bioremediated (repaired and renourished biologically) nutrient-rich biomass (plant and animal-based renewable organic matter) derived from decayed organic waste and is the final product of composting that is produced for use as a soil and groundwater fertilizer and conditioner.

It is made up of the broken-down mixed remains of different organic materials that have undergone decomposition and have been transformed by the removal of structural bonds, harmful pathogens (disease-causing organisms), and simplified its constituent compounds into absorbable nutrients that are beneficial to the ecosystem.

Compost is a nutrient and mineral-rich biomass sometimes called humus that contains beneficial organisms like worms, fungal mycelium (the vegetative parts of a fungus, or a similar bacterial colony with dense filamentous branching hyphae), and other microorganisms that can be used as a potent fertilizer.

What is a Composter?

There are two basic related definitions that can apply to the term composter.

  1. A composter is a vessel that is designed for or that can be used to contain and decompose organic material like garden and kitchen waste into usable compost for fertilization. A composting bin is a type of composter.
  2. A composter is a person who operates a composting vessel; i.e. one who uses a container to contain and decompose kitchen and garden waste to compost. Or a person who generally uses any composting method to dispose of waste and generate manure or compost in an eco-friendly way.



Composting can be defined as the biological decomposition process of heterogeneous solid and semi-solid organic materials under controlled aerobic, moist, and self-heating conditions to produce humic (the important components of humus) substances and stable biomass that is rich in soluble nutrients micronutrients, and minerals that will be a potent organic fertilizer for plants, groundwater, and soil.

The practice of composting by biodegradation has the beneficial results of the neutralization of several plants and soil pathogens as well as many other toxic contaminants. It also stabilizes the organic constituents, cuts methane generation from landfills, and accumulates nutrients, micronutrients, and some metals.

Decomposition is a natural process that all dead organic matter must undergo given suitable conditions with or without any human input and all living things will die and decompose eventually. Composting is based on this premise.

However, composting only speeds up the process by providing a suitable environment for decomposing organisms like nematodes, sowbugs, bacteria, fungi, and other decomposers to thrive and thereby optimally carry out decomposition on the material.

Composting is a mostly human-influenced natural biochemical (relating to microscopic chemical processes within living organisms) process that is considered a bioremediation (biologically repairing and replacing nourishment) technique.

Due to the fact that the process is based on biodegradation by the decomposition of organic materials, it is often erroneously equated as being the same process and interchangeable with biodegradation.

Biodegradation and composting are very similar because although there is a fundamental difference between them, the process of composting is based largely on controlled and contained biodegradation and both sequences involve the decomposition of organic material.

The difference is that although composting can occur naturally from the accumulation of plant debris (litter) from shedding, weathering, and death, the process in modern usage refers mostly to the artificially/human-initiated form.

Whereas biodegradation generally refers to the natural decomposition process of organic material. Composting can therefore be referred to in other words as controlled biodegradation. Or biodegradation in a controlled and contained environment.

Types of Composting

Compost grinder Processing bioremediated soil and compost material
Compost grinder processing bioremediated soil and compost material

There are three basic types of composting that can be carried out for the effective degradation of organic materials by their decomposition through the action of microorganisms and the enhanced environmental conditions.

  1. Aerobic composting
  2. Anaerobic composting
  3. Vermicomposting

Aerobic Composting

Aerobic composting is simply defined as the decomposition of complex organic matter using microorganisms that require oxygen to metabolize the material for the purpose of deriving simpler organic nutrients that can be used as an organic fertilizer.

Anaerobic Composting

Anaerobic composting can be defined as the use of putrefaction or the decomposition by digestion of complex organic matter using anaerobic microorganisms or microorganisms that do not require oxygen to digest organic material for the purpose of large-scale waste management, and the production of biogas (a mixture of organically derived gases constituted of mainly methane and carbon dioxide).

Additionally, for the generation of renewable energy, and deriving digestate (fibrous and sludgy biomass remaining after anaerobic digestion of a biodegradable feedstock) for use as a soil conditioner or a substrate (an organic substance on which an enzyme acts).


Vermicomposting is the process of using various suitable species of worms and microorganisms in a vermicomposter (a vessel used for vermicomposting) or a contained and controlled environment to decompose and convert organic material (usually food and vegetable waste) into humus-like biomass called vermicompost.

Vermicompost consists of a mixture of bedding material, organic waste, and vermicast or worm castings, humus, or manure (product of the decomposition of organic material by earthworms).

Other types of composting

Other types of composting whose categories fall under the main three include:

Mesophilic Composting

This process takes place at relatively low temperatures, not too hot or cold, that mesophiles (organisms that grow under low temperatures) can thrive and carry out decomposition in which is generally between twenty to forty-five degrees Celsius (20°C-45°C)

Thermophilic Composting

This process takes place at relatively high temperatures that thermophiles (microorganisms that thrive in heat) thrive and carry out decomposition in which is roughly from fifty degrees Celsius and above (50°C +)

Backyard Composting

Backyard compost bins
Backyard compost bins

Backyard composting simply identifies domestic and small-scale composting that can be carried out in the backyard of a personal home or within the confines of a private compound for subsistence purposes.

It distinguishes small-scale domestic-level composting from large-scale commercial-level composting. They both use the fundamental principle of the natural decomposition of organic matter to derive nutrient-rich biomass that can be used as a fertilizer but each has significant differences based on their overall individual scales.

Types of Backyard Composting

The three common types of backyard composting are cold composting (also called passive composting), hot composting (also called active composting), and hole composting (also called trench composting).

Cold Composting

Cold or passive composting as the name suggests refers to backyard mainly anaerobic composting (in instances where aeration is not carried out) that involves very little human input other than the addition of organic waste to the pile for the process of decomposition to run its natural course.

The vessel/composter or designated spot/area for the pile of organic waste to be decomposed is established and the material is accumulated at the site without any further measures to aid, optimize, enhance, or catalyze the process beyond its natural course.

The cold composting method typically takes a much longer time to decompose the material because of the lack of any optimizing input like aeration from turning or injection of air, water, and other enhancements that catalyze the process.

Due to the deficiency in oxygen availability, the decomposition process ultimately becomes anaerobic decomposition. The temperature produced is usually not hot enough to destroy certain pathogenic organisms and some types of seeds and spores.

Hot Composting

Hot or active composting is the process of recycling food and vegetative waste by their biological aerobic decomposition in a conditioned and controlled vessel or environment to produce a stable nutrient-rich humic substance while actively modifying the environment to catalyze the process and optimize the output.

Active composting takes a shorter time to obtain the product but requires a lot of attention to the process to ensure optimal conditions like the correct ratio of carbon/nitrogen, and of other compost constituents, adequate aeration, and hydration for the efficient decomposition of the feedstock.

When executed properly, hot composting has the potential to destroy most of the unwanted seeds, spores, weeds, and toxic pathogens contained in the organic material.

Hole Composting

Hole or trench composting is a method of recycling organic food and vegetative waste by putting them in holes or trenches in the ground where they will decay and eventually decompose anaerobically conditioning and fertilizing the soil in the surrounding area.

This is one of the easiest and perhaps most concealed and therefore least odorous types of composting through the decomposition of organic material that can be carried out domestically or otherwise.

It has been shown to help nearby plants develop root systems that conserve more water than average and has the benefit of not only being concealed but also eliminating the odor that typically accompanies decomposing organic waste.

Trench composting has the disadvantages of being a single-use option that cannot accommodate repeated deposits of organic material for subsurface decomposition. The produced material cannot be collected for fertilization elsewhere.

Composting Bin

Composting Bin
Composting Bin

A composting bin is a specially built or adapted container or vessel that is designed to catalyze the natural decomposition of organic material through effective aeration and moisture retention.

The correct design and operation of the compost or composting bin with adequate containment, a sufficient supply of oxygen, moisture, and periodic turning will ensure ideal conditions for the high temperatures necessary to decompose and transform the organic material into compost while neutralizing harmful pathogens present.

Compost Fertilizer

A fertilizer is any natural or synthetic material or substance that can be applied to plant tissues, soil, or groundwater to supply one or more essential nutrients that are beneficial to plant health, growth, and productivity.

Nutrients in soil and groundwater can be lost or severely depleted in several different ways although leaching and pollution are common causes of nutrient loss. Fertilizer helps to supply some, most, or all the essential minerals and other nutrients needed for healthy soil and plants.

These nutrients include major elements like the main and most important three Nitrogen (N), Phosphorus (P), Potassium (K), together known as the big three (NPK). Other major elements include Calcium (Ca), Magnesium (Mg), and Sulfur (S).

Other less crucial elements needed by plants are referred to as trace elements because they are only needed in trace amounts. They include; Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), Boron (B), and Molybdenum (Mo).

Synthetic fertilizers have inherent disadvantages that arise from their usage. Most of the problems associated with non-organic fertilizers are related to potentially harmful synthetic substances and compounds that may affect the health of the consumer. The residue from such compounds is also often harmful to wildlife and the environment at large.

For these reasons of damage to the health of people, wildlife, and the environment, there has been a general conscious effort to use organic fertilizers instead of the synthetically generated types to control mass pollution.

Properly constituted compost serves as a very effective organic fertilizer that can greatly improve the health and utility of soil, crops, and other beneficial plants. Organic fertilizer also has the benefit of not containing harmful synthetic material that can have long-term environmental damaging effects.

Well-made compost should contain five basic components that complement each other for the right balance of nutrients in the final product. The components include:

  • Green plant material which is rich in nitrogen
  • Brown plant and other organic material that is rich in carbon
  • Water or the appropriate volume of moisture is necessary for any biotic process
  • Soil is needed as the base medium for some of the microbial activity
  • Air is an important requirement for aerobic decomposition

Other important nutrients that are released in the end product are phosphorus, potassium, and trace quantities of calcium, magnesium, iron, and zinc.

The humus (amorphous and stable dark organic component of soil) rich biomass (residual organic material derived from plants or animals) that is produced will invite and cause the thriving of beneficial organisms like earthworms and other macro and microorganisms.

Composting Toilet

Composting toilet
Composting toilet

A composting toilet is a type of specially designed dry toilet (toilet that does not use water for flushing) that processes human waste through organic decomposition by microbiota (ecological communities of commensal, symbiotic, and pathogenic organisms) and sometimes with catalytic organic additives, into compost that can be used as a fertilizer or conditioner for plants and soil.