Electronic waste

Fast technology development and implementation of new models of electronic apparatus, resulted in permanent buying of new equipment, since repair of the old one is not profitable any more. For that reason many old pieces of the equipment become waste material, although even 90% of such electronic waste might be repaired and fit for use.

There are three main groups of consumers that produce electronic waste:

  1. small companies and households

  2. big companies, institutions and government

  3. producers of original equipment

Electronic waste contains precious metals as well (such as gold). On the other side such a waste contaminates the environment, because various toxic materials are released.

Electronic waste may be hazardous and non-hazardous.

Electronic waste contains very often poisoned and carcinogenic substances, therefore it is harmful for human beings and for the whole planet as well. Dangerous substances contained in the electronic waste are:

Mercury – becomes the most dangerous when water is polluted with mercury. Mercury is settled in living organisms through the nutrition chain. It may damage vital organs like brain, kidneys, as well as fetus. It is contained in sensors, relays, thermostats, mobile apparatus, batteries and LCD screens. Around 22% of the world production of mercury rely on the electronic equipment.

Phosphor – contains high level of poison, upon coming in contact with phosphor, urgent medical assistance is required. It is used for coating of CRT monitors to obtain better resolution.

Lead – can damage central and periphery nerve system, cardio-vascular system, kidneys and reproductive organs. It is contained in monitors and main boards components.

Toners – are classified as carcinogenic and its particles come in contact with humans by inhalation, which causes irritation of respiratory tract. Main component of the black toner is a pigment.

Cadmium – can cause durable damage of kidneys and of total human organism. It is used to stabilize plastics and it is present in various types of chips.

Plastics – the most applied form of the plastics is PVC, which by burning releases CO2 that causes pollution of atmosphere.

Hexavalent chromium – easy absorbed and can damage DNA. It is used as protection of corrosion, for making ornament and computer case fixture.

BFR (Bromine Flame Retardants) - is used in plastic cases to prevent from burning.

Barium – even very short disposure to barium can cause muscle weakness, can damage heart, liver and spleen. It is applied in CRT monitors to protect of radiance.

Beryllium – carcinogenic and causes lung cancer. It is applied as a component of in main boards due to its characteristics - it is light and hard metal.


Computer equipment contains various components like PCB, switches, monitors and cathode tubes (CRT monitors), or panel of liquid crystals (LCD and TFT monitors), batteries, hard discs, light generators (lamps), condensers, resistant boxes, relays sensors, connectors etc.

These components contain substances which may pollute environment. They are mostly hard metal components like mercury, cadmium, chromium, halogenous materials (PCB), PVC material, bromine flame retardants, arsenic, asbestos, nickel etc.

Computer equipment which can not be repaired for re-use is transferred to the recycling department to be dismantled on components, which is performed on working tables especially designed for that purpose. The process of dismantling is followed simultaneously by the process of separation. Skilled workers separate and classify the computer components on recyclable (secondary raw material) non-recyclable.

Generally from one computer unit (computer, CRT monitor and printer) the following materials are obtained calculated the total weight of the unit:

  • plastics and plastic elements 22,5 mass%

  • metals and metal elements 35,0 mass%

  • PCB (Printed Circuit Boards) 7,5 mass%

  • Other 35 mass%

Recyclable components are deposited into special containers with designations for:

  • Plastics and plastic parts

  • Cables

  • Bail units

  • Power

  • Metal and metal parts

  • Toner cartridges

  • Other material

Non-recyclable components are packed in specially designed containers with tag designations:

  • PCB (Printed Circuit Boards)

  • Memory units

  • Hard discs

  • Floppy discs and other optical units (CD ROM)

  • Processors

  • Batteries

  • Connectors

  • CRT screens

  • Condensers

  • Other material


One of the most important computer components and small household appliances is monitor or TV screen, i.e. cathode tube of CRT screen.

The cathode tube of the CRT screen consists of two parts: conical glass and screen glass. Screen glass contains lead which protects from radiance. It is of large thickness and there is a photo-sensitive layer from inside, which produces the image. Another part is supporting glass which is coated with barium-oxide from inside and has the similar composition as the screen glass, but it contains greater percentage of lead.

CRT screens contain substances that are harmful to human health. For that reason it is recommendable that skilled people from an authorized company who handle the screens in a safety way, pick up the waste in closed containers.