Effective Recycling Methods for Various Waste Materials
Recycling of Various Materials
Paper and Paperboard Recycling
Recycling paper and paperboard constitutes 20-25% of Municipal Solid Waste (MSW). A considerable portion ends up as waste or is incinerated, which is environmentally and economically undesirable.
Paper, due to its high cellulose content, should be considered a raw material for manufacturing new paper. The cost of recycled paper production is lower, requiring less water and energy than production from wood. Technically, obtaining paper from waste paper is very similar to paper production from wood.
Glass Recycling
Glass makes up approximately 7-10% of MSW. It is an inorganic product with a very long lifespan and does not naturally degrade. Discarding it leads to mere accumulation.
Due to the large amount of glass waste, reuse is necessary. The recycling process involves separating glass by color, grinding, and cleaning it to form a granulate called calcine. These granules are added directly to the new glass production process, which lowers the melting point of the mixture.
Agricultural Waste Recycling
Mainly composed of organic matter, agricultural waste was once used for combustion, soil enrichment, or animal feed if it had nutritional value. Currently, all organic matter originating from living material is encompassed under the generic term biomass and is considered a renewable energy source. Energy uses of biomass include: direct combustion, pyrolysis (decomposition of biomass at high temperatures without oxygen to produce fuel, charcoal, and oils), and anaerobic digestion (biomass is transformed into biogas that can be used as fuel).
Plastics Recycling
In general, plastics are very stable products, virtually non-degradable by atmospheric or biological agents, insoluble in almost all solvents, and resistant to heat and moisture. Many burn well but generate black smoke, odors, and toxic products, making open-air incineration unsuitable.
Their high stability necessitates large, often useless, landfill sites. Recovery is often more expensive than new procurement. Most plastics are incompatible, requiring careful selection and cleaning for recycling. Recycling plastics presents significant difficulties in recovery techniques and economic profitability.
Rubber Recycling
A third of manufactured rubber becomes waste and is not biodegradable. It possesses great elasticity, preventing compaction. The largest portion of vulcanized rubber is used in tire manufacturing, which is currently subject to recycling. Several possibilities exist: retreading, pyrolysis, reuse as protective elements, and obtaining molded rubber products.
Waste Electrical and Electronic Equipment (WEEE)
These wastes often contain toxic substances dangerous to human health and the environment. Some companies have started recycling electronic equipment components after their useful life. Legislation, valid from 01-01-06, prohibits electronic and electrical equipment from containing cadmium, lead, chromium, etc., and requires manufacturers to recycle equipment.
Radioactive Waste
These are materials containing radioisotopes in higher proportions than permitted by applicable law.
The bulk comes from nuclear plants but also originates in research and some clinical equipment. They can be solid, liquid, or gaseous.
Gaseous waste from nuclear plants, once processed to remove some of its radioactivity, is released directly into the atmosphere.
Solid waste with medium and low radioactivity is mixed with concrete and placed in drums, stored at the plant initially, and then transported to its final location.
Solid wastes with high radioactivity are stored first in concrete pools filled with water at the plant and then sent to reprocessing plants where combustible material is recovered. The remaining non-combustible material is transported to a specific, geologically stable area and buried in corrosion-resistant containers where there are no water streams.