Biodegradability

Biodegradability

Biodegradability is the ability of substances and organic materials to decompose into simpler substances due to the enzymatic activity of microorganisms. When the biological process is completed, the total transformation of the initial organic substances into simple inorganic molecules such as water, carbon dioxide and methane is obtained.

The phenomenon of biodegradation is part of the natural cycle of life on earth, based on carbon. Thanks to the activity of photosynthesis of plants and algae, and the inexhaustible solar energy, the carbon dioxide in the atmosphere is absorbed to synthesize the sugars and other substances used by vegetables to grow and develop. Through the food chain, the flow of matter and energy passes from the plants to the herbivores and from these to the carnivores. When plant and animal organisms die, microorganisms - always present in the environment - are nourished by organic material through biodegradation processes that release water and carbon dioxide into the atmosphere, thus closing the cycle.

By imitating and valuing these natural processes, organic waste from human activities can also be eliminated through biodegradation.

For this operation to be effective it is necessary to identify the ideal environment in which this phenomenon can be maximized and it is necessary to define a process duration that is "industrializable" and compatible with the production rhythms of this organic waste.

In nature, each organic waste has its degradation times, straw and wood use more time than starch and cellulose. In the same way, in cold and dry environments the biodegradation processes are slower than in hot and humid environments.

This means that biodegradation depends very much on the chemical nature of the substance or matter to be biodegraded and on the environment of biodegradation. The environments in which biodegradation occurs at a good pace and which allow industrial management are those of composting and anaerobic digestion.

In these systems, therefore, organic solid waste can be treated, including processed organic waste (for example biodegradable plastic) that has a rate of biodegradation compatible with these treatments. In the case of composting, a mature compost (which is a fertilizer) will be obtained and in the case of anaerobic digestion (followed by stabilization in composting), biogas (and therefore energy) and compost will be obtained.

Another biologically active environment is the soil: some materials can be completely biodegraded in the soil and this property can be used in specific applications such as mulching (covering the soil).

Compostabilidad

Compostability is the ability of an organic material composted by the composting process. This process takes advantage of the biodegradability of the initial organic materials to transform them into a final product that takes the name of compost. Compost is therefore the result of the disintegration and aerobic biodegradation (ie in the presence of oxygen) of material (usually residues) organic: mature compost is similar to a fertile substrate and rich in organic substances used as fertilizer.

Composting can be practiced at the household level on a very small scale or industrial scale. The latter is fed with organic waste from households and residues from agricultural production and other sectors and is carried out in specific plants to ensure proper management of the process.

What happens in the composting plant is not very different from what sometimes can be seen in the field: piles of organic material (waste, dung, sawdust, wood shavings, etc.) produce heat and steam exhaling as if they were burning but no flame. Actually in those piles it is being carried out biodegradation by microorganisms that consume nutrients and transform the initial residue in a set of organic substances called precisely compost.

In industrial plants the product is sterilized and stabilized for lacking pathogenic microbes and putrescible material. In addition, prior to marketing, quality is controlled, since it must meet certain requirements established by law.

Defining oxo-degradable

The oxo-degradable technology is based on the introduction of a pro-degrading agent in the manufacturing process conventional plastic. The decomposition is carried out through a multistep process using chemical additives to initiate the degradation.

Oxo additives are the mixture of these four compounds:

Polyolefin PE or PP depending on the plastic support to be added.
Metal salt, which can be manganese, cobalt, nickel, iron, copper, etcetera.
An antioxidant to protect the metal salt during the extrusion phase.
An antioxidant that stabilizes the plastic guaranteeing life within the finished product

Oxo-degradable products degrade in any environment, internal or external, in which there is oxygen without water. The (plastic controlled lifetime) is a technology used in the manufacturing stage of ordinary plastic. It is intended that this plastic instead of staying 500 years on earth, is oxo degrade in less time. The degradation which occurs is the result of an oxidant and cellular phenomenon. Plastic decomposes in millionths particles not visible to the human eye.