What makes something decompose

See the full definition for decompose in the English Language Learners Dictionary. Nglish: Translation of decompose for Spanish Speakers. Britannica English: Translation of decompose for Arabic Speakers.

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Log in Sign Up. Save Word. Definition of decompose. Synonyms for decompose Synonyms break down , corrupt , decay , disintegrate , fester , foul , mold , molder , perish [ chiefly British ], putrefy , rot , spoil Visit the Thesaurus for More.

Choose the Right Synonym for decompose decay , decompose , rot , putrefy , spoil mean to undergo destructive dissolution. Examples of decompose in a Sentence Bacteria and fungi help decompose organic matter.

Recent Examples on the Web Over time, some will decompose , crumble and fall away, leaving small voids. First Known Use of decompose , in the meaning defined at transitive sense 1. It may also refer to a state in which a particular substance is being reduced into its original elements. However, in biology, decomposition refers to a biological process of breaking down an organic material into smaller constituent parts. The decomposition of organic substances is ecologically significant.

It plays a part in the nutrient cycle. It is an essential process of recycling matter in the biosphere. Dead bodies of organisms are decomposed through the action of various decomposers. A decomposer is an organism whose ecological function involves the recycling of nutrient s by performing the natural process of decomposition as it feeds on decaying organisms.

Anaerobic decomposition takes place in nature, as in the decomposition of the organic muds at the bottom of marshes and in buried organic materials to which oxygen does not have access.

Intensive reduction of organic matter by putrefaction is usually accompanied by disagreeable odors of hydrogen sulfide and reduced organic compounds which contain sulfur, such as mercaptans any sulfur-containing organic compound.

Putrefactive breakdown of organic material takes place anaerobically. Organic compounds break down by the action of living organisms that do not require air in the normal sense.

These organisms use nitrogen, phosphorus, and other nutrients to live and to develop cell protoplasm, but they reduce the organic nitrogen to organic acids and ammonia. The carbon from the organic compounds which is not utilized in the cell protein is liberated mainly in the reduced form of methane CH 4. A small portion of carbon may be respired as carbon dioxide C0 2. Since anaerobic destruction of organic matter is a reduction process, the final product, humus, is subject to some aerobic oxidation when put on the soil, that is, it may appear to decompose further after being exposed to air.

This oxidation is minor, takes place rapidly, and is of no consequence in the utilization of the material on the soil. In other words, much less heat is generated in anaerobic decomposition than in aerobic decomposition. The lack of heat generated in the anaerobic destruction of organic matter is a definite disadvantage if contaminated materials areused for composting.

High temperatures are needed for the destruction of pathogens and parasites. In anaerobic decomposition the pathogenic organisms do eventually disappear in the organic mass, as a result of the unfavorable environment and biological antagonisms.

The disappearance is slow, and the material must be held for periods of six months to a year to ensure relatively complete destruction of pathogens, such as the eggs of Ascaris, nematodes which are among the most resistant of the fecal-borne disease parasites in wastes. Therefore, make compost this year and use it next year. However, organic material can be decomposed anaerobically to produce compost. For instance, a heavy plastic bag can be used to decompose grass clippings or other high nitrogen materials, shredded leaves, kitchen trimmings, a small amount of stable manure or other compostable materials.

However, as anaerobic compost can have a strong odor and may need to be aired prior to using , it is not usually the first choice for home owners. For more details see Structures. For example, it takes place on ground surfaces such as the forest floor, where droppings from trees and animals are converted into a relatively stable humus. There is no accompanying bad smell when there is adequate oxygen present.

In aerobic decomposition, living organisms, which use oxygen, feed upon the organic matter. They use the nitrogen, phosphorus, some of the carbon, and other required nutrients.

Much of the carbon serves as a source of energy for the organisms and is burned up and respired as carbon dioxide C0 2. Since carbon serves both as a source of energy and as an element in the cell protoplasm, much more carbon than nitrogen is needed. Generally about two-thirds of carbon is respired as C0 2 , while the other third is combined with nitrogen in the living cells.

However, if the excess of carbon over nitrogen C:N ratio in organic materials being decomposed is too great, biological activity diminishes. Several cycles of organisms are then required to burn most of the carbon. When some of the organisms die, their stored nitrogen and carbon becomes available to other organisms.

As other organisms use the nitrogen from the dead cells to form new cell material, once more excess carbon is converted to C0 2. Thus, the amount of carbon is reduced and the limited amount of nitrogen is recycled.

Finally, when the ratio of available carbon to available nitrogen is in sufficient balance, nitrogen is released as ammonia. Under favorable conditions, some ammonia may oxidize to nitrate. Phosphorus, potash, and various micro-nutrients are also essential for biological growth. These are normally present in more than adequate amounts in compostable materials and present no problem.

During composting a great deal of energy is released in the form of heat in the oxidation of the carbon to C0 2. For example, if a gram-molecule of glucose is dissimilated under aerobic conditions, to kilogram calories kcal of heat may be released.

Oxidation at thermophilic temperatures takesplace more rapidly than at mesophilic temperatures and, hence, a shorter time is required for decomposition stabilization. The high temperatures will destroy pathogenic bacteria, protozoa microscopic one-celled animals , and weed seeds, which are detrimental to health or agriculture when the final compost is used. Aerobic oxidation of organic matter produces no objectionable odor.

If odors are noticeable, either the process is not entirely aerobic or there are some special conditions or materials present which are creating an odor. Aerobic decomposition or composting can be accomplished in pits, bins, stacks, or piles, if adequate oxygen is provided. Turning the material at intervals or other techniques for adding oxygen is useful in maintaining aerobic conditions.

This temperature can also be maintained for several days before further aeration. The heat necessary to produce and maintain this temperature must come from aerobic decomposition which requires oxygen.

After a period of time, the material will become anaerobic unless it is aerated. It requires a considerable amount of oxygen and produces none of the characteristic features of anaerobic putrefaction. In its modern sense, aerobic composting can be defined as a process in which, under suitable environmental conditions, aerobic organisms, principally thermophilic, utilize considerable amounts of oxygen in decomposing organic matter to a fairly stable humus.

Decomposition of organic material in the compost pile depends on maintaining microbial activity. Any factor which slows or halts microbial growth also impedes the composting process. Efficient decomposition occurs if aeration, moisture, particle size, and a sufficient source of carbon and nitrogen are in evidence. Oxygen is required for microbes to decompose organic wastes efficiently. Some decomposition occurs in the absence of oxygen anaerobic conditions ; however, the process is slow, and foul odors may develop.

Because of the odor problem, composting without oxygen is not recommended in a residential setting unless the process is conducted in a fully closed system see plastic bag method under Composting Structures.

Mixing the pile once or twice a month provides the necessary oxygen and significantly hastens the composting process. A pile that is not mixed may take three to four times longer to decompose.

Raising the pile off the ground allows air to be drawn through the mass as the material decomposes. Coarse materials should be placed on the bottom as the pile is built or placed in the pile and removed after the decomposition starts. The more oxygen, up to at least percent, the more quickly the biodegradation will take place.

Adequate moisture is essential for microbial activity. A dry compost will not decompose efficiently. Proper moisture encourages the growth of microorganisms that break down the organic matter into humus. If rainfall is limited, water the pile periodically to maintain a steady decomposition rate. Add enoughwater so the pile is damp but not soggy. Avoid over watering.

Excess water can lead to anaerobic conditions which slow down the degradation process and cause foul odors. If the pile should become too wet, turn it to dry it out and restart the process. Grinding the organic material before composting greatly reduces decomposition time. The smaller the size of the organic refuse particle, the more quickly it can be consumed by the microbes.

A shredder is useful for chipping or shredding most landscape refuse and is essential if brush or sticks are to be composted. A low-cost method of reducing the size of fallen tree leaves is to mow the lawn before raking. Wind-rowing the leaves into long narrow piles one foot high will make the shredding process more efficient.

If the mower has an appropriate bag attachment, the shredded leaves can be collected directly. However, grinding is entirely optional. Temperature of the compost pile is very important to the biological activity taking place.

Low outside temperatures slow the activity down, while warmer temperatures speed up decomposition. These high temperatures will help destroy weed seeds and disease organisms within the pile.

There are many organisms that breakdown organic materials. Most are not seen by the human eye, but they are there throughout the process. Others that are large enough to see, are usually associated with the later breakdown stages. The most important organisms in the breakdown process are the bacteria. The bacteria present in any given pile are dependent upon the raw material present, amount of air in the pile, moisture conditions of the pile, pile temperature and numerous other factors.

Compostable organic materials normally contain a large number and many different types of bacteria, fungi, molds, and other living organisms.

Only very limited data are available regarding the variety of different organisms and their specific functions. It appears that more species of bacteria are involved in aerobic decomposition than in anaerobic putrefaction. Although many types of organisms are required for decomposition of the different materials, the necessary variety is usually present in the materials to be composted, and the organisms thrive when environmental conditions are satisfactory.

During decomposition, marked changes take place in the nature and abundance of the biological population. Some of the many species will multiply rapidly at first but will dwindle as the environment changes and other organisms are able to thrive under more varied conditions.

Temperature and changes in the available food supply probably exert the greatest influence in determining the species of organisms comprising the population at any one time. Aerobic composting is a dynamic process in which the work is done by the combined activities of a wide succession of mixed bacteria, actinomycetes, fungi, and other biological populations.