Ans.

Treatment of Gaseous Waste: – The air is polluted by the effluents of gases coming out of various industries because dust particles, carbon particles, smoke, etc. are mixed in these gases.  The following two devices are used in industrial areas to free the air from these harmful wastes.

(i) Electrostatic Precipitator: – This is the best device for removing dust particles or other solid particles mixed in the smoke coming out of chimneys during the combustion process in industries.  It has negatively charged electrodes.  When the positively charged dust particles mix with the smoke being expelled from the chimney, the negative electrodes attract them, causing them to settle down, thus releasing the gas free of harmful dust particles from the chimney.  In thermal power plants, these devices are installed in the chimneys to release the ash from the smoke.

(ii) Wet Scrubber: – Wet brushes or wet scrubbers clean the air by wetting it with water.  The exhaust gases of the industries pass through a large chamber in which water is sprayed.  The solid particles mixed with gases get wet and become heavy and settle down and the clean air freed from them comes out.  In addition, water-soluble harmful gases such as sulfur dioxide, nitrogen dioxide, hydrogen sulfide, ammonia, etc. air pollutants are also released from the air by this process.

In this way, the environment can be kept clean by waste management, human health can be protected, biodiversity can be maintained and resources can be conserved through recycling and recycling.