Tag: not for breathing not for drinking

• An electrostatic precipitator is a device that removes suspended dust particles from a gas or exhaust by applying a high-voltage electrostatic charge and collecting the particles on charged plates. It can remove 99% of particulate matter from thermal power plant exhaust.
• BOD(Biochemical oxygen demand) is a measure of, the amount of oxygen that require for the bacteria to degrade the organic components present in water/wastewater. Hence based on the BOD it is possible to estimate the amount of organic matter in sewage water.
  
• Hence b and c are correct statements.
• So, the correct answer is 'b and c correct'.

• Compressed natural gas (CNG) (methane stored at high pressure) is a fuel which can be used in place of gasoline, diesel fuel, and propane/LPG. 
• CNG combustion produces fewer undesirable gases than the aforementioned fuels.
• The main difficulty of was laying down pipelines for delivering CNG through distribution points up to the CNG pumps and to ensure uninterrupted supply.
• Hence it is difficult to lay down pipelines for delivery of CNG.
• So, the correct answer is 'Option E'.

Catalytic converter is a device in automobiles that controls the exhaust emission. It has some expensive metals which acts as a catalyst on pollutants such as platinum, palladium and rhodium. These catalysts converts harmful nitrogen oxides into nitrogen gas and carbon monoxide into carbon dioxide. Thus, the correct answer is 'Platinum, Palladium and Rhodium'.

An electrostatic precipitator is widely used to eliminate particulate and gaseous pollutants from the air with the help of a high-voltage electrostatic charge. Thermal power plants release various harmful gases and particulate matter in the environment such as sulfur dioxide, carbon dioxide, nitrogen oxides, and other harmful emissions. Electrostatic precipitators are known to be very effective in removing the harmful chemicals present in the emissions. They are the best device for controlling air pollution.

MTBE is a gasoline additive, used as an oxygenate to raise the octane number. It is one of a group of chemicals commonly known as oxygenates because they raise the oxygen content of gasoline. It has been used in gasoline at low levels to replace tetraethyl lead and to increase its octane rating to help prevent engine knocking. Oxygenates help gasoline burn more completely, which causes emission of CO$ _2$ instead of CO.

• Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials.
•  Incineration and other high temperature waste treatment systems are described as "thermal treatment".
•  Incineration of waste materials converts the waste into ash, flue gas and heat.
• Hence, Incinerator is not a device used to control a particulate matter.

• Coal burning results in the generation of large quantities of coal residues, which contains very fine particles that tend to become airborne and which contribute to the formation of suspended particulate matter (SPM). 
  
  
• An electrostatic precipitator (ESP) is a filtration method that removes fine particles, like dust and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding the flow of gases through the unit.
  
  Hence, option D is correct.

The Cyclone Collector is the device that is used for minimizing air pollution by trapping the suspended particles like coarse dust generated due to activities like mining, cement and wood factories. These are the dry scrubbers that work on the principle of inertia. Cyclone collector work similar to a centrifuge, but with a continuous feed of dirty air.

The prevention of addition of undesirable and toxic substances will result in prevention of pollution. Banning atomic blasts would prevent soil and water pollution from the harmful release of radiations. Use of electrically operated automobiles would prevent the release of oxides of sulphur, nitrogen and carbon and so, air pollution would be prevented. Sewage treatment would remove the toxic components and would prevent water pollution.