INORGANIC WASTE: CHARACTERISTICS, CLASSIFICATION, TREATMENT - ENVIRONMENT - 2025

The inorganic wastes are non - biological waste from anthropogenic processes (generated by humans). By their nature, they are non-biodegradable or very long-term degradable waste. This category includes chemical waste, electrical and electronic waste, metal waste, plastics, paper and cardboard, glass, synthetic fabrics or tires, among others.

Inorganic waste can be classified according to various criteria, including its material state, source of origin or composition. Due to their material state they are solid, liquid or gaseous and, due to their source of origin, they are urban, industrial and mining, among others.

Inorganic waste. Source: Muntaka Chasant

Regarding its composition, inorganic waste can be classified into a wide variety of types. Some of these are plastics, paper and cardboard, glass, and radioactive waste.

As they are polluting waste, they must be treated properly and can be classified into those that can be recycled or reused and those that cannot.

Inorganic waste must be processed and disposed of in such a way that its negative impact on the environment is minimized. The treatment required for this depends on the nature of the particular inorganic waste. For example, glass is crushed and melted for recycling, while radioactive material is sealed in containers and stored in geological repositories.

The prior step to any treatment is the proper classification and disposal of inorganic waste. For this, suitable containers are available for each type of waste or special places for its deposit (for example, clean points).

Inorganic waste that is part of electronic waste is subjected to selection, disassembly, extraction and smelting processes. Subsequently, the components are reused, recycled or discarded.

characteristics

Non-biological nature

Their main characteristic is that they do not have organic origin, that is, they are not derived from living beings and they are not fermentable. This, in turn, implies that they cannot be integrated back into natural cycles or, if they do, require long periods of time.

Therefore, they must be subjected to special treatments to avoid their negative impact on the environment. Oil residues are considered inorganic and can be biodegraded by certain bacteria.

However, its derivatives such as plastics require hundreds of years or even millennia for their degradation.

Highly polluting

Being non-organic in nature, in most cases they are highly polluting when introduced into natural environments. On the other hand, the elements that are artificially separated from their natural cycles, upon being reintroduced to the environment, generate serious imbalances.

Classification

Hazardous inorganic waste. Source: Mampato

Inorganic waste can be classified according to its state, source of origin or according to its composition.

- According to its material state

Solid inorganic waste

It includes metal scraps, plastics, paper and cardboard, glass, rubble, electronic waste, batteries and batteries.

Liquid inorganic waste

It covers all inorganic waste disposed of through domestic, industrial, mining and agricultural and livestock effluents.

Gaseous inorganic waste

They are those gases that are emitted as a result of industrial processes, combustion engines or burning of inorganic waste.

- According to its source of origin

Urban waste

They are those inorganic wastes that are produced in homes, offices, restaurants and educational establishments. It includes paper and cardboard, as well as remains of glass, bottles, ceramic objects or lamps, among others.

In addition, electrical and electronic devices, which include a variety of plastic and metallic materials. Likewise, plastic objects of various kinds such as cutlery, plates, bottles and bags mainly.

Household effluents incorporate residues of various chemical elements. These include detergents, chlorine, thinners, paints, oils (including used motor oils), and pesticides.

Industrial waste

This category is extremely broad and can be subdivided according to the different industrial branches, each generating particular inorganic waste. In general, the industry produces solid inorganic wastes, effluents and gases, being in many cases highly polluting.

A particularly dangerous type of industrial waste is blast furnace smelting sludge, due to its high content of heavy metals and other toxic elements. Likewise, radioactive waste from thermonuclear plants represents a serious environmental problem.

Mining waste

The most problematic inorganic wastes from mining are heavy metals such as mercury, lead or arsenic, which are highly polluting.

Oil waste and petroleum derivatives

Oil operations generate so-called heavy metal-rich extraction sludge, as well as oil waste throughout the process.

The petrochemical industry also produces highly polluting waste and discarded plastic and tire waste is derived from petroleum.

Agricultural and livestock waste

Agricultural and livestock activities use a large amount of inorganic products such as pesticides and inorganic fertilizers. The waste derived from these is not recyclable and causes serious pollution problems.

Hospital waste

Hospitals and medical centers in general produce various organic and inorganic wastes, of special care given the nature of the activity they carry out.

Inorganic waste includes syringes, scalpels, and drug residues. Electronic waste is also generated with highly dangerous radioactive elements.

Construction waste

It includes construction debris, metal debris and others that generally represent a problem for disposal due to their volume.

- According to its composition

Plastics

Due to its versatility, plastic is the material par excellence of the contemporary era, which is why it is part of the majority of manufactured objects. Plastics occupy the first place in the composition of inorganic waste.

Inorganic plastic waste. Source: Venkat2336

Most of plastic waste is bottles, bags and cutlery, although it is also found in electronic waste, car scrap and a variety of utensils.

Plastics are highly polluting because their degradation time is measured in hundreds and thousands of years. On the other hand, even degrading itself to small particles, it continues to pollute natural environments.

For example, in the so-called garbage islands of the oceans, the main component is small plastic particles. It is estimated that around 275 million tons of plastic waste were generated in 192 coastal countries in 2010.

Paper and paperboard

They rank second in proportion in inorganic waste. For example, in the administrative and educational sectors waste paper is produced in large quantities.

For its part, cardboard is part of the waste mainly as packaging waste (boxes). The advantage of this type of inorganic waste is that it can be easily recycled.

Glasses, crystal, porcelains and related

Glass is made up of silica, sodium carbonate, and limestone, and glass includes potassium hydroxide and lead oxide. For its part, porcelain is composed of kaolin, feldspar, quartz and water.

Both glass, crystal and porcelain are produced at different melting temperatures, therefore they should not be mixed in the waste phase. Glass must have specific containers, while porcelain and glass are not normally recycled.

There are also glass containers and containers that can contain dangerous substances, making recycling difficult. Glass objects, like broken thermometers, contain mercury, just as flasks of laboratory chemicals can contain toxic substances.

Metals

This includes metal equipment components and general scrap, such as copper from wiring and tin from solder. Likewise, there are kitchen utensils, cans and cars that can be recycled.

Chemicals

Inorganic wastes of a chemical nature are very diverse and are generated in all areas of human activity. From household detergents to textile printing dyes to waste from the chemical industry.

Paints and oils

This includes paints, colorants, varnishes, lacquers, sealants, enamels, and inorganic oils (including used motor oil). Most of these products have components derived from petroleum.

Batteries and batteries

They incorporate a variety of materials, including copper, zinc, aluminum, lithium, manganese dioxide, mercury, and acids. They are highly polluting and it is enough to point out that an alkaline battery can pollute 175 thousand liters of water.

Tires

Discarded tires are one of the serious environmental problems, since a large amount of oil is used in their manufacture. For example, a truck tire consumes the equivalent of half a barrel of crude oil.

In addition, other materials such as natural rubber, carbon, steel, cloth, and chemical additives are included.

Electrical and electronic equipment (electronic waste)

These appliances have a complex structure and composition that includes a variety of materials and components. They include metals, plastics, gases, liquids, so once discarded they must have a special treatment.

Radioactive materials

They are waste materials or equipment that contain radioactive elements and originate in industry, research and medicine. Due to their high risk, they receive special treatment depending on their radioactive level.

Treatment

Inorganic waste, not being biodegradable or being biodegradable in very long periods, must be properly treated to avoid environmental contamination. These wastes require various treatments to dispose of them, depending on their composition.

- Selection

The first step for those inorganic waste that can be recycled or reused is to selectively dispose of it in the disposal process. For this, there must be containers specially designed for the reception of each type of waste.

Inorganic waste recycling. Source: Gelpgim22 (Sergio Panei Pitrau)

It is not always easy to decide in which container to deposit certain waste. For example, tetrabrik containers are externally made of cardboard, but they have an internal plastic lining and for this reason they are recycled together with plastic.

In the case of scrap metal and electronic waste, special areas must be provided for their reception and processing (clean points).

- Recyclable

Paper and paperboard

Paper and cardboard are made of cellulose of plant origin and their recycling helps to reduce deforestation. Some of the recycled paper comes from the original production process as scraps that are ground up and recycled. Another part is discarded paper due to low quality or consumed and discarded (newspapers, magazines, catalogs, documents).

The times in which a portion of paper can be recycled are limited, because the fibers are broken in the pulp production process. This is compensated by adding virgin pulp and the proportion is increased each time the paper is recycled.

On the other hand, the paper processing method is important, since if chlorine-free bleaching methods are not used, recycling can lead to contamination.

Glass

Glass can be recycled indefinitely without losing its properties, but it is necessary to make an adequate prior selection of the types of glass. For example, heat resistant glasses should not be mixed with ordinary glass, because they have different viscosity.

Another criterion to take into account is the color, since glasses of different colors should not be mixed.

Metals

Metals are largely recovered by processing the discarded devices that contain them and these can be reused depending on their nature. The most recovered metals are iron and steel, although gold, silver, rhodium, palladium and beryllium are also reused.

Each metal follows a different process for recycling, according to its characteristics. In most cases they are smelted to obtain pure bars that will be raw material for various industrial processes.

Plastics

As with glass, plastic requires proper selection for recycling. This is because the different types of plastics cannot be mixed in foundry due to differences in molecular weight.

Inorganic waste separation. Source: User: Nino Barbieri

Therefore, an initial classification of the type of plastic in PET, PVC, HDPE, LDPE, PP or PS must be made. In this sense, it is important to separate PET plastic bottles, which are the ones that can be recycled more easily.

Tires

Around 50% of discarded tires are recycled and can be largely reused. Another portion of the tires is used as fuel in cement kilns.

They can also be used as construction elements for fences and other structures.

Batteries and batteries

Due to their high contaminating potential, discarded cells and batteries must be deposited in specific containers and properly processed. These wastes contain heavy metals and corrosive chemicals, which can cause serious environmental pollution problems.

There are many types of batteries with various components, so each type has its own recycling process. Once separated by type, they undergo crushing processes, separation of metal, plastic and other components.

Subsequently, these wastes are treated in ovens to separate other elements such as zinc.

Electronic trash

It is normally stored in suitable warehouses where reusable or recyclable components are dismantled and recovered.

- Not recyclable

Porcelain and glass

Glass, due to its lead oxide content, and porcelain due to its clays, are not recycled. They are usually shredded together with other non-recoverable waste and sent to landfills.

Chemicals

Most of the chemical substances that act as inorganic waste are released into the environment as effluents or gases. Therefore, its recovery and recycling is not possible.

Effluents must be treated in order to purify the water of organic and inorganic contaminants before being returned to nature. As for gases, they must be filtered at their sources of origin to prevent their entry into the atmosphere.

Paints and oils

Paints and oils, once used, cannot be recycled due to their chemical composition. The paints are adhered to the surfaces where they were applied, and can be polluting agents due to their content of toxic elements such as lead.

In the process of applying paints, especially by compressors, suspended particles pollute the air. In this way they penetrate the respiratory system of humans, and can cause serious illnesses.

Heavy metals in foundry sludge

Treatment of heavy metal rich wastes in foundry sludge (metal industry waste) is quite difficult. This is due to the toxicity of these elements. The traditional option is by melting in blast furnaces, but the toxic elements accumulate in the furnace.

Microwave-based and plasma melting methods that are more effective are being tested today.

Complex materials

There are certain discarded materials whose complex composition and manner of use make recycling difficult. For example, disposable diapers, pads, wax paper, stickers and others.

Radioactive material

Due to the danger of radioactive materials, they must be stored in safe conditions. These conditions depend on the level of radioactivity in the waste and its half-life.

In the case of highly radioactive materials, whose half-life exceeds 30 years, they are stored in deep geological deposits (former salt mines, for example).

References

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