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Environmental pollution.ppt compatibility mode Document Transcript

  • 1. 8/21/2007 Lecture - 11ENVIRONMENTAL POLLUTION from PROCESS INDUSTRIES In this lecture Pollution - Introduction by man, waste matter or surplus Pollution and Pollutants energy into the environment, which directly or indirectly causes damage to man and his • • Types of Pollution environment • Effects of Pollution • Managing Pollution 1
  • 2. 8/21/2007 The IssuePollutant - A substance or effect whichadversely alters the environment by changingthe growth rate of species, interferes with the • We use Resources extensivelyfood chain, is toxic, or interferes with health,comfort amenities or property values of people and then are NOT responsible for • The Consequences !!! Aral Sea Man made environmental disaster 2
  • 3. 8/21/2007 EFFECTS ON BIOSPHERE 1. Damage to human health by specific chemical substances present in the air, food, Pollution and effects water and radioactive material 2. Damage to natural environment affecting vegetation, animals, crops, soil and water Minamata Disease 3. Damage to visual quality by smoke, fumes, dust, noise and waste (Jinzu river, Japan) 4. Damage by carcinogens, radioactive materials and excessive noise Learning from the Past … Japan Bioaccumulation• Fueling consumerism …. Doubling income …… three basic consumer items ….. e.g DDT zooplankton small fish large fish birds water 0.04 ppm 0.5 ppm 2 ppm 25 ppm 3
  • 4. 8/21/2007Storyof Bold eagleIn from Paracelsus .... Toxicity is Quantity related ..USA Anything and Everything is toxic if the dose is made so !! Paracelsus (1493-1541) Waste takes many forms Drinking water and death ! .. • Woman dies after water- drinking contest SACRAMENTO, Calif. – A woman who competed in a radio station’s contest to see how much water she could drink without going to the bathroom died of water intoxication, the coroner’s office said Saturday. 2007 ! 4
  • 5. 8/21/2007 TYPES OF POLLUTION Water Pollution • Water Pollution • Air Pollution • Land Pollution • Noise Pollution • Thermal Pollution • Electro Pollution • Visual Pollution Water Pollution – with what? Water Pollution• Water ( about 99%) Inorganic materials - alkalis, acids, inorganic salts, ammonia, Solids phosphates, etc. Heavy metals - chromium, mercury, nickel, copper,•• Carbohydrates cadmium etc. Proteins These are referred to as Disinfection byproducts - trihalomethanes Other harmful substances - organochlorides etc.•• Fats ‘organic material’ Physical factors - turbidity, colour, temperature etc.• Nutrients (Nitrogen and Phosphorus)• Microorganisms. (On average there are about 10 million per ml of wastewater. Many are pathogens) 5
  • 6. 8/21/2007 Industrial Sources Responsible for Organic PollutionOrganic Pollutants DistilleryInorganic Pollutants CanningHeavy metal Pollutants organic Depletion of DO Sugar matterPathogenic Pollutants Cheese Making 6
  • 7. 8/21/2007 Industrial Sources Responsible for Inorganic Pollution Dissolved Oxygen Sources Effluent Problems Fertilizer algal blooms reduced light Soap and detergent penetration ammonia and Rubber and latex re-aeration phosphates (eutrophication) Agricultural farms EutrophicationFertiliser Application 7
  • 8. 8/21/2007 Industrial Sources Responsible for Heavy Metal Pollution Sources Effluent Problems Paper and pulp Mercury - Minamata disease Chromium toxic to aquatic life Tanneries Iron and self purifying Nickel organisms Textile Lead Zinc Toxic to humans Coke-oven Arsenic Cadmium - Itai-itai disease Metal plating Copper Bio accumulate Silver Sources Discharging Pathogenic Organisms b) Air PollutionSources Organism Diseases Air is considered safe when it contains noSewage Cholera, typhoid, Bacteria dysentery, harmful dust and gases.Farm slurry gastroenteritis diarrhea, salmonellosis Polluted air affects:Hospital waste Viruses polio, hepatitis, Protozoa Diarrhea, dysentery, HumansMedical laboratory (Giardia, amebiasis Animals Cryptosporidium)Food processing Helminths Roundworm infestation, Vegetation pinworm, beef tapeworm, Materials pork tapeworm 8
  • 9. 8/21/2007 Effects from Air Pollution Air Pollution • Global warming has • Ozone depletion No (Ozone hole) Boundaries • Acid Rain • Various respiratory illnessesMetal foundry refining in early industrial Germany, 1870s Pollution of air Particulate Matter PM10 (<10ìm) - Dust (e.g. cement dust, bagasse, foundry dust and wind blown solid dust) - Mist - Smoke - Carbon black - Aerosols 9
  • 10. 8/21/2007 Air Pollution and Health The Problem of DUST SPM PM 10 PM 2.5 etc. Radioactive nucleidsSome Polluting Process Industries TRANSPORTATION Three modes of transport Sulfuric Acid Plants • Air ( airplanes etc.) Thermal Power Stations • Sea (ships, boats etc.) Nitric Acid Plants • Land (automotive & locomotive) Cement Plants Products of combustion of fuels are CO, CO2, Foundaries NOx, hydrocarbons, particulate matter and Plastic Industries traces of SO2, formaldehyde and Pb. 10
  • 11. 8/21/2007 c) Land PollutionUrbanization and Concentration of PopulationMunicipal Solid WasteIndustrial Waste and Hazardous WasteUncontrolled “Land Treatment” This is within ourBurning open dumps and forest fires universityDeforestationMining and Erosion d) Noise Pollution Exposure to prolong noise affects speech, hearing, general health and behaviour. Noise Levels – dB Intensity frequency periods of exposure and duration 11
  • 12. 8/21/2007 Human hearing and Frequency Intensity (Loudness) • Measure of acoustic energy of the sound vibrations • Expressed in terms of sound pressure • Decibels (dB) are the unit of measurement on the Loudness scale0 16 Hz 20 kHz 5 MHz Physical Characteristics of Sound How sound is measured • Measurement and human perception of •Pressure, P, usually Pascals Sound involves three basic physical P = 1/f •Frequency, f, usually Hertz characteristics: I = W/A •Intensity, I, usually W/m2 – Intensity L’ = log (Q/Qo) •Bels, L’, derived from logarithmic ratio – Frequency •Decibels, L, derived from bels L = 10*log (Q/Qo) – Duration E.g. Implications of the decibel scale: doubling sound level would mean that the sound will increase by 10*log2 = +3dB Ten times the sound level = 10*log10 = +10dB 12
  • 13. 8/21/2007 Comparative Noise Levels (dB) Adding decibels Walkman (1/2 volume) 94 Telephone Dial tone 80 Talking at Three Feet 65 Quiet Urban Daytime 50 Quiet Urban Nighttime 40 Quiet Rural Nighttime 25Industrial Noise Sources Electropollution !• Metal fabrication (pressing, grinding, chipping etc.)• High pressure burners in furnaces• Turbines - a growing• Compressors problem• Pumps• Welding machines• Cranes and other vehicles• Pipe lines carrying high velocity fluids and solids•Vibrating and grinding equipment 13
  • 14. 8/21/2007 Power Lines and Pollution Management Leukemia• “..children living in proximity to high voltage powerlines are at increased risk of childhood leukaemia, but in finding effects up to 600 metres away, they http://news.bbc.co.uk/1/hi/health/3967073.stm Pollution can be controlled by invoke electric field corona ion effects as a possible causal proper choice of preventive mechanism. and remedial measures Prof. Denis Henshaw, Professor of Human Radiation Effects at the University of Bristol http://www.electric-fields.bris.ac.uk/ Techniques are changing … Wastewater Treatment Cleaner Waste water treatment Production Sustainable Pollution Development Prevention Preventive Curative Recycling Pollution Control Complexity of Environmental Issue Volume reduction Strength reduction Physical Chemical Biological Dispersion 1960 1980 1990 14
  • 15. 8/21/2007 Typical Wastewater Processing Air emissionsWastewater Water Primary Secondary Tertiary Treatment Treatment Treatment Primary sludge Secondary Sludge Tertiary Sludge 15
  • 16. 8/21/2007 Physical Methods Biological waste water treatmentObjective Aerobic treatment Solvent extractionRemove solid or Anaerobic treatment •liquid pollutants • Evaporationbased on density Distillation The organic load is defined by the Biological Oxygen Demand (BOD). •difference or other Filtrationphysical property In aerobic systems the water is aerated with • Reverse Osmosis compressed air (in some cases oxygen).(eg. SS or floating • Electrodialysissolids) Anaerobic systems run under oxygen free • • Adsorption conditions – biogas is a useful product. Activated Sludge System• Metabolism: Bacterial decomposition and hydrolysis Organic Nitrogen NH3 NH3 + O2 NO2- + Energy NO2- + O2 NO3- + Energy Nitrification Anaerobic Zone Aerobic Zone 16
  • 17. 8/21/2007 Chemical Wastewater Treatment Ozonation …...• Neutralization - NaOH, Ca(OH)2, HCl, H2SO4• Coagulation and Flocculation - Alum, FeSO4,• Oxidation - Sodium hypochlorite• Disinfection - Cl2, O3, NaOCl Dye Solutions subjected to ozonation Air Pollution Control • Use tall stacks Air Pollution and Control • Source reduction by process and raw material changes (eg. Improved furnace design and low S fuel) • Recover valuable material (eg. Hg) • Bag filters, scrubbers, ESP, cyclone separators • Absorption, adsorption, combustion and catalytic reaction 17
  • 18. 8/21/2007 Blue Skies over Puttalam 80% of the air pollution load is contributed by the transport sector Land Pollution Control 3R Principle• Integrated Solid Waste Management Good agricultural practices • Reduce•• Remediation of polluted soils Prevention of erosion and silting • Reuse• Containment of hazardous waste and waste water treatment using land• treatment techniques • Recycle 18
  • 19. 8/21/2007 Paper Deaf and Blind School CompostProduction Abans Env Services / Paper collection Glass ( 3 types) Glass Factory Plastics (all types) Different plastic recyclersUniversity Colour Code – Solid Waste Noise Pollution ControlBlue – waste paperOrange – Plastics (milk cartons , cups)Green – Food waste • Control noise at source by proper choice of equipment, design modification, mounting and proper layout • Isolation or use of baffles • Use of ear protection devices 19
  • 20. 8/21/2007Desiccated Coconut Industry DC industry Sri Lanka 20
  • 21. 8/21/2007 Waste takes many forms Air EmissionsSome additional slides for information Materials, Energy, Water, Products, Labour, By-Products Capital Solid Waste Waste Energy, Wastewater fertilisers sewage (liquid domestic Harmful Substances and industrial waste) Sources Substances ProblemsEutrophication The process of minerals minerals Disinfection byproducts trihelomethanes carcinogenic esp. nitrates esp. phosphates Agricultural organochlorides persistent organic material Pesticides (DDT) bio accumulate eutrophication Acids and alkalis inorganic minerals affect biological algal bloom life, affect toxicity of CN-, S- competition consumers cant for light consume fast enough Plastic, lubricant, PCB persistent, lethal rubber, paper even at low level dead plants dead algae Pharmaceutical, Phenols toxic to fish,MO & Petrochemical aquatic life detritus 21
  • 22. 8/21/2007 Physical EffectsPhysical Parameter Causative ProblemSuspended Solids china clay, peroxide, settlement, turbidity metal salts reduce light, photosynthesis organic solids reduce DOTemperature Cooling water from lower DO, speed up organic power plants matter degradationOil and grease Refineries, terminals Prevents O2 exchange, storage tanks lethal to birdsColour pigments, dyes aesthetics, toxic, reduce light penetrationFoaming anionic detergents, aesthetics, carry SS & surfactants pathogens, affects aeration Occupational Health & Safety Occupational safety and health is the discipline concerned with protecting the safety, health and welfare of employees of the industry and the general public. Safety in process design can be considered under the following broad headings. 1. Identification and assessment of the hazard 2. Control of hazards 3. Control of the process 4. Limitation of the loss. 22