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Dr. Rajarshi MitraAssistant Professor and Head
Department of Environmental Science
Vivekananda College, Thakurpukur, Kolkata – 700 063
POLLUTION CONTROLStrategies and Practices
Control Strategies
Control at Source
Recycle and Reuse
End of Pipe
Treatment
Raw materials /
Fuel alteration
Process alternatives
Byproduct Recovery
Primary, Secondary and
Tertiary treatment
Control at Source
Alternative Fuel / Raw materials
Process alteration
Pollution means the wastage. A fuel with high ash content
or sulphur concentration is expected to cause higher level of air pollution than a cleaner option.
Liquid or gaseous fuels with less non-combustible impurities are always cleaner than the solid fuels.
Similarly a raw material having high amount of impurity leads to higher pollution problem. Impure raw materials in turn also put economic burdens to the company.
Process modification leads to efficiency enhancement by:
Making the existing process more efficient, i.e. reduced wastage. For example if a car engine drive it 12kms in litre of petrol it is using more resource and causing more pollution than a car with 15 kms mileage.
Switching over to a new technology which reduce pollution.
Recycling and Reuse
Recycling and Reuse technology is defined as the process of using the same resource again and again after value addition to it following a single use.
In industrial set up and with chemical waste materials it may not be possible to recycle or reuse any material in most of the cases, but in that case a few other strategies may be adopted. 1. Byproduct recovery 2. Value addition of waste material to make
wealth from the waste.
End of Pipe system
This is the treatment strategy, where the treatment of the exhaust or effluent is done once the pollutants have been generated. Although this strategy is being used in most of the cases due to its easy implementation procedure, but is considered less effective in view of development, because:
It treats the waste material and thus incur additional money flow.
No value addition and byproduct recovery having potential economic benefit is possible in this system.
It releases the final or treated effluent to the environment directly.
End of pipe treatment for Wastewater
Tertiary Treatment:This is the last phase of water treatment, where the treated effluent are kept or treated again mostly on the basis of retention time and natural degradation process in Effluent pit or Oxidation pond.
A comprehensive Effluent Treatment Plant
Activated Sludge Process
Trickling Filter
End of Pipe treatment for Air pollution control:
Major pollutants to control:
Particulate mattersFlue gasesAcid Vapours
Cyclone Precipitator.Electrostatic Precipitator.Fabric filter/ Bag filter / Baghouse.Scrubber – Wet, Dry and Venturi.
Cyclone or cyclone precipitator
Electrostatic Precipitator (ESP)
Fabric Filter / Bag House
Scrubbers
Solid Waste disposal
Segregation At source Reuse of inert materials like glass, metal goods. Reuse of inert materials like construction debris etc. in
road construction, earth work. Recycling of Metals, glass, plastics. Organic composting or vermi-composting of market
biodegradable waste. Immobilization of toxic waste through solidification and
vitrification. Dumping on ground. Sanitary Landfill technology.8
THANK YOU