Industries have caused severe pollution of our natural resources. Industries cause environmental degradation through four main types of pollution i.e. air pollution, water pollution, land pollution or soil degradation, and noise pollution.
Smoke contains undesirable gases like carbon dioxide, sulphur dioxide and carbon monoxide, besides solid and liquid particulate matter, in the form of dust and spray mist, which cause air pollution. Air pollution affects the health of humans, animals and plants alike and also causes damage to buildings.
Water pollution is caused by the discharge of untreated chemical waste like dyes, detergents, acids, heavy metals like lead and mercury, pesticides, fertilisers, and plastics from industries, into fresh water bodies like rivers and lakes. Solid wastes like fly ash, phospo gypsum, and iron and steel slag also cause water pollution.
The industries that cause major amount of water pollution are paper and pulp industries, oil refineries, tanneries and electroplating industries. The discharge of hot water from thermal power plants into rivers before cooling is called thermal pollution of water. Radioactive waste, hazardous chemicals, glass, plastic, industrial effluents and non-biodegradable garbage are the main agents of land pollution. Rain water falling on polluted land dissolves and carries many of the pollutants further into the ground and pollutes groundwater.
Loud noise can lead to irritation, loss of hearing, and an increase in blood pressure and heart rate. Industrial machinery, construction activities, generators, and equipment like saws and pneumatic drills are mainly responsible for noise pollution. One of the most important steps for the control of environmental degradation is treating hot and polluted wastewater from industries before releasing it into our rivers and lakes.
Wastewater treatment involves:
- Primary treatment through screening, grinding, flocculation and sedimentation.
- Secondary treatment through bacterial action to digest harmful chemicals.
- Tertiary stage of stirring with chemicals to neutralise remaining harmful waste.
Treated wastewater can be recycled for reuse in industrial processes. Rainwater harvesting can be used to meet the requirements of water for industrial processes.
Legal provisions must be made to regulate the use of groundwater for industrial use. Smoke stacks, filters, scrubbers, and electrostatic and inertial separators remove a large amount of harmful particles from industrial smoke. The emission of smoke itself from industries can be reduced by using more efficient fuels like oil and natural gas in place of coal.
Industrial and generator silencers, and sound-absorbing material are available to reduce the noise level in industries. Industrial workers can use earphones and earplugs for individual protection of health and hearing.
National Thermal Power Corporation or NTPC is a major electricity generation and distribution company in India. NTPC has demonstrated how conservation of environment and natural resources can happen simultaneously with industrial growth by:
- Adopting latest technical knowhow
- Minimising waste
- Providing green cover
- Reducing environmental pollution
- Continuous monitoring