MECHANICAL RECYCLING: CONCEPTS AND TECHNIQUES

The idea of ​​using waste is not new; however, it has been established in an expressive way, not only for economic reasons, but also as a way to minimize impacts on the environment 5 .

The American Environmental Protection Agency (EPA / USA) defines mechanical recycling as “the collection, processing, marketing and use of materials considered to be garbage” 5 . The definition found in the dictionary, in turn, refers to recycling as “the process through which the same material goes through , already used to make the same product or an equivalent product”. Thus, according to these definitions, recycling consists of a process of transformation of materials, previously separated, in order to enable their recovery. These materials can have two origins: industrial process waste or post-consumer products.

The factors that encourage the recycling of materials stem from the need to save and preserve natural resources and the possibility of minimizing waste, which reduces the volume to be transported, treated and disposed of. Recycling reduces environmental and public health problems, as well as economic and social problems resulting from the inadequate disposal of solid waste. When waste is disposed of in landfills (sanitary or industrial, depending on their characteristics), recycling helps to minimize the amount of landfilled waste, which increases the useful life of these disposal sites 6 .

Recycling, from an economic point of view, provides a reduction in the cost of waste management, with less investment in treatment facilities and final disposal, and promotes job creation. Socially, it allows the population to participate in the separation process, making them aware of their responsibility in the face of environmental problems 6 .

2.2 – Recycling of Industrial Waste

In the case of industries that carry out the reprocessing of the polymer and return it to the production line, recycling brings gains in competitiveness and productivity. Currently, the recycling of industrial waste, in the production process that generated it, is carried out in a large number of companies. This practice is established as new technologies and equipment for environmental control are developed and causes a parallel reduction in energy costs by reducing the generation of this waste, making the product more competitive.

“Industrial waste management” has a significant cost and includes the stages of packaging, collection, storage, transport, treatment and final disposal. Therefore, the reduction of waste represents a preventive strategy in the company’s management and is carried out under three aspects: reduction in the source of generation, recycling and treatment of the portion that cannot be reused, aiming at reducing the volume of waste generated.

Recycling is one of the important activities in reducing waste (reducing the volume disposed of in landfills) and must be carried out after the possibilities of reducing waste in the generating source have been exhausted.

2.3 – Post-consumer recycling

The products discarded by society or urban waste, have been reused in a volume above what is imagined, either through formal or informal recycling, carried out by individual collectors or grouped in cooperatives. The most popular materials for recycling are: paper and cardboard, plastics, glass, ferrous and non-ferrous metals and, to a lesser extent, wood, rubber and even rags 6 . However, when recycling is not possible, the waste undergoes treatment prior to its final disposal or, in extreme cases, is disposed of directly on the soil.

The term reuse or reuse is used in recycling processes to designate the waste that is used without having undergone a transformation, that is, it refers to the reuse of the material or packaging for the same purpose, for example, soda bottles, glasses of tomato jam and extract, reused to serve liquids; pots of mayonnaise and ice cream, to store groceries, and printer or copier paper, for draft.

The recovered term, on the other hand, indicates that the material has been reprocessed in order to obtain a useful product again, or has undergone a treatment to make it possible to regenerate.
Currently, plastic has become a widely accepted waste for the recycling process because, both in the form of films (plastic bags, etc.), as well as in the rigid form (tubes and connections), it finds technology available for its reuse .

In Brazil, in 2005, there was a 3% increase in the amount of recycled plastics in relation to 2004, reaching approximately 768,000 tons of material, according to data from the Plastivida Socio-Environmental Institute of Plastics 33 . This number means approximately 18% of the apparent consumption of resins, which was about 4,272,000 tonnes in 2005, according to ABIQUIM, boosting various segments involved with polymers, such as equipment manufacturers, transformers, academic and commercial institutions, among others .

Figure 2-1 shows the evolution of the PVC recycling index and table 2-1 shows data on the installed capacity and production of post-consumer plastic recyclers in Brazil.