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Waste disposal


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Solid waste disposal methods and excreta disposal methods.

Waste disposal

  1. 1. Just pay attention to the lecture. The slides can be downloaded from<br /><br />
  2. 2. SOLID WASTE<br /><br />
  3. 3. Some terms we need to know<br />REFUSE:<br />Solid or semisolid waste matter produced in the normal course of human activities. Generated from street sweepings, markets, stable litter, industrial refuse, commercial refuse, etc.<br />RUBBISH:<br />Solid wastes originating in houses, commercial establishments, industries, excluding garbage and ash.<br />GARBAGE:<br />Animal & vegetable wastes resulting from the handling, storage, sale, preparation, cooking and serving of food.<br />ASH:<br />Residue from burning of wood, coal, charcoal and other combustible materials used for cooking and heating purposes in houses, industries etc.<br /><br />
  4. 4. Sources of solid wastes<br />Street refuse<br />Market refuse<br />Stable litter<br />Industrial refuse<br />Domestic refuse<br />In most of the countries the per capita daily solid waste produced is between 0.25 to 2.5 Kg<br /><br />
  5. 5. Galvanized steel dust bin with cover (for households) – 0.05 to 0.1 cubic feet per capita per day.<br />A bin with capacity of 1.5 cubic feet for a family of 5 members if collection is done every 3 days.<br />Public bins.<br />Storage of solid wastes<br /><br />
  6. 6. House-to-house collection<br />Mechanical transport<br />Dustless refuse collector<br />Collection of solid wastes<br /><br />
  7. 7. Methods of solid waste disposal<br />INSANITARY METHODS<br />Hog feeding<br />Dumping<br />SANITARY METHODS<br /><br />
  8. 8. Methods of solid waste disposal<br />SANITARY METHODS<br />Sanitary landfill/ Controlled tipping<br />Composting<br />Incineration<br />Manure pits<br />Burial<br />Biogas plant<br /><br />
  9. 9. INSANITARY METHODS<br />Hog feeding<br />Dumping<br />Refuse dumped in low lying areas<br />Bacterial action over time, decreases volume of refuse which is gradually converted into humus<br />Disadvantages<br />Smell<br />Unsightly appearance<br />Free access to flies, rodents, hogs, dogs etc.<br />Dispersal by wind<br />Pollution of surface and ground water<br /><br />
  10. 10. Dumping<br /><br />
  11. 11. SANITARY METHODS<br />1. Sanitary landfill / Controlled tipping<br />Laying of dry and condensed refuse in a trench or other prepared area with intervening earth coverings.<br />Anaerobic digestion of the refuse takes place. The process takes 4-6 months to complete.<br /><br />
  12. 12.<br />
  13. 13. 4-12 meter<br />2-3 meter<br /><br />
  14. 14. Trench method<br />Level ground<br />Trenches 4-12 m wide, 2-3 m deep<br />Refuse is compacted and then covered with excavated earth<br />Ramp method<br />Sloping terrain<br />Area method<br />Land depressions, disused quarries, pits<br />May need soil from outside sources to cover the compacted refuse<br /><br />
  15. 15. SANITARY METHODS<br />2. Composting<br />Method of combined disposal of refuse and nightsoil or sludge.<br />Organic matter breaks down under bacterial action, producing “compost” – used as manure.<br /><br />
  16. 16. Three methods of composting<br />BANGALORE METHOD<br />MECHANICAL COMPOSTING<br />VERMI-COMPOSTING<br /><br />
  17. 17. Bangalore method<br /><ul><li>Anaerobic composting; also called “Hot fermentation process”
  18. 18. IISc, Bangalore – Indian Council of Agriculture Research</li></ul><br />
  19. 19. 800 metre<br /><br />
  20. 20. 4.5 – 10 m<br />1.5 – 2.5 m<br />90 cm<br />A Trench excavated for composting<br /><br />
  21. 21. Earth<br />25 cm<br />REFUSE<br />5 cm<br />NIGHTSOIL<br />15 cm<br />REFUSE<br />NIGHTSOIL<br />5 cm<br />NIGHTSOIL<br />15 cm<br />REFUSE<br />4-6 months<br />Humus<br />Anaerobic decomposition<br /><br />
  22. 22. Mechanical composting<br />Refuse<br />Screening<br />Pulverizing equipment<br />Pulverized refuse + Sewage/Sludge/Nightsoil<br />Incubation<br />(Temperature, pH, Aeration, Moisture controlled)<br />4-6 weeks<br />Complete composting<br /><br />
  23. 23. Vermicomposting<br /><ul><li>A method of garbage disposal</li></ul>Garbage<br />Earthworms<br />2-3 months<br />Compost<br /><br />
  24. 24. SANITARY METHODS<br />3. Incineration<br />Suitable for areas where land is not available for sanitary landfill<br />Example: Hospitals<br />Disadvantages:<br />Expensive<br />No useful by-product<br />Air pollution <br /><br />
  25. 25. SANITARY METHODS<br />4. Manure pits<br />Used in rural households<br />Covered with earth after each days dumping<br />Two pits<br />Within 5-6 months decomposed refuse which is used as fertilizer<br /><br />
  26. 26. SANITARY METHODS<br />5. Burial<br />Suitable for small settlements/camps<br />Decomposed matter may be ready for use as manure within 4-6 months<br />1.5 m<br />40 cm<br />1 m<br />200 persons<br />1 week<br />2 m<br />20-30 cm<br /><br />
  27. 27. SANITARY METHODS<br />6. Biogas plant<br />Biogas is produced by the anaerobic breakdown of solid waste /excreta.<br />Biogas (Methane, CO2, Hydrogen) can be used as a fuel for any heating purpose, such as cooking.<br /><br />
  28. 28. EXCRETA<br /><br />
  29. 29. Spread of disease from excreta<br /><br />
  30. 30. Sanitation barrier<br /><br />
  31. 31. Methods of excreta disposal<br />INSANITARY METHODS<br />Open defecation<br />Conservancy system/Cartage<br />SANITARY METHODS<br />WATER CARRIAGE SYSTEM<br /><br />
  32. 32. Methods of excreta disposal<br />SANITARY METHODS<br />1. Pit latrine<br />2. Pour flush/Water seal latrine<br />a. Simple pit latrine<br />b. VIP latrine<br />c. ROEC<br />3. Composting latrine<br />Direct (Shelter over pit) & Indirect (Offset pit)<br />Single pit & Double pit<br />PRAI & RCA latrine<br />4. Aquaprivy<br />5. Septic Tank<br />6. SulabhShauchalya<br />7. Chemical closet<br />8. Biogas plant<br />Trench latrine<br />Shallow trench latrines<br />Deep trench latrine<br />Bore hole latrine<br />9. Latrines suitable for camps and temporary use<br /><br />
  34. 34. 1. Open defecation<br />2. Cartage (Conservancy system)<br /><ul><li>Example: Bucket latrine
  35. 35. Disadvantages:
  36. 36. Smell
  37. 37. Flies
  38. 38. Health risk to people handling the excreta
  39. 39. Health risk from food crops fertilized with raw excreta</li></ul>Bucket latrine<br /><br />
  41. 41. 1a. Simple pit latrine<br /><br />
  42. 42. Location of a pit latrine<br /><br />
  43. 43. Advantages:<br />Easy and cheap to construct<br />Slab and shelter can be reused<br />Excreta are isolated<br />Disadvantages:<br />Unpleasant odors<br />Flies<br />Advantages & Disadvantages<br /><br />
  44. 44. 1b. VIP latrine & 1c. ROEC<br />Ventilated Improved pit latrine<br />Reed Odorless Earth Closet<br /><br />
  45. 45. 0.5 m<br />Semi dark<br />Shelter<br />Ventilated Improved Pit Latrine<br /><br />
  46. 46. Windshear effect drawing air up the vent pipe<br /><br />
  47. 47. 2. Pour Flush/Water-seal Latrine<br />Pour flush latrines use a pit for excreta disposal and have a special pan provided with a “water-seal” of 20-30 mm.<br />They need 1-3 liters of water for flushing each time they are used.<br />Advantages:<br />No fly or smell problems<br />Easy maintenance<br />Disadvantages:<br />Water is needed for their operation<br />More expensive than pit latrines<br /><br />
  48. 48. Water seal latrine<br /><br />
  49. 49. The Water Seal<br /><br />
  50. 50. 2a. Direct & Indirect WS Latrine<br />Direct<br />Indirect<br /><br />
  51. 51. Double pit WS Latrine<br />2b. Single & Double pit WSL<br /><br />
  52. 52. 2c. PRAI & RCA Latrine<br />PRAI Latrine was developed by the Planning, Research & Action Institute, Lucknow<br />RCA latrine was developed by the Research Cum Action project of the Ministry of Health<br /><br />
  53. 53. The RCA Latrine<br />Location<br />Squatting plate<br />Pan<br />Trap<br />Connecting pipe<br />The pit<br />Superstructure<br />Maintenance<br />Modifications<br /><br />
  54. 54. Location<br /><ul><li>Depends on porosity of soil and ground water level
  55. 55. Usually, at least 15 m away from water source</li></ul>Squatting plate<br /><ul><li>Made of impervious material (cement concrete)
  56. 56. 3’x3’x2”
  57. 57. Raised footsteps</li></ul>Pan<br /><ul><li>Receives nightsoil, urine and water</li></ul>Trap<br /><ul><li>A bent pipe connected to the pan
  58. 58. Holds water and serves as a water seal (2 cm depth)</li></ul><br />
  59. 59. Connecting pipe<br />The pit<br />Maintenance<br /><ul><li>Needed when pit is sited away from squatting plate
  60. 60. Not needed in Direct type RCA Latrine
  61. 61. 3.5” diameter with a bend at the end
  62. 62. Covered, rectangular/circular
  63. 63. 75 cm diameter, 3-3.5 m deep
  64. 64. Underneath squatting plate(Direct) or offset (Indirect)
  65. 65. Regular cleaning of the squatting plate
  66. 66. Flushing with 1-2 lts of water after every use</li></ul>Superstructure<br /><br />
  67. 67. Modifications<br /><ul><li>Using prefabricated squatting plate/pan made of china clay
  68. 68. Using a septic tank instead of the pit</li></ul><br />
  69. 69. 3. Composting Latrine<br />Composting latrines are shallow vaults, into which excreta, kitchen waste and similar wastes are added.<br />The waste & excreta breakdown together to produce compost – fertilizer.<br />Two shallow vaults are usually provided - when one is full it is covered with soil and left for at least two years – compost.<br />The vaults must not receive water<br /><br />
  70. 70. Advantages:<br />Does not need to be moved and new vaults do not have to be dug.<br />Produces compost used as a fertilizer<br />Disposes kitchen waste as well<br />Disadvantages:<br />More expensive and more difficult to build than VIP or WS latrine<br />Advantages & Disadvantages<br /><br />
  71. 71. 4. Aquaprivy<br />The aquaprivy is a water tight tank filled with water into which excreta fall via a drop pipe, connected to a seepage pit (soakaway) to dispose of sullage and effluent.<br />Drop pipe must reach below surface of the water.<br /><br />
  72. 72. The AQUAPRIVY<br /><br />
  73. 73. Advantages:<br />Cannot be blocked with bulky anal cleaning material<br />Nil problem with odor or flies<br />Can be connected to a sewerage system at a later date<br />Disadvantages:<br />Expensive to build<br />Need large volumes of water to work<br />Water seal may be hard to maintain<br />Tanks must be emptied about every 3 years<br />Advantages & Disadvantages<br /><br />
  74. 74. 5. Septic Tank<br />Septic tanks are watertight chambers (single, double or multi chambered) which receive excreta and wastewater.<br />They are connected to a soakaway which receives liquid overflowing from the tank.<br /><br />
  75. 75.<br />
  76. 76.<br />
  77. 77. Solids (“sludge”) settle down and are purified by anaerobic digestion.<br />The liquids (“effluent”) undergoes aerobic oxidation in the upper layers of the soil, outside the septic tank proper.<br />Working of Septic Tank<br /><br />
  78. 78. Advantages:<br />Isolation and treatment of excreta<br />No odor or fly problems<br />May be connected to sewerage system at a later date<br />Disadvantages:<br />High cost of construction<br />Need for periodic mechanical emptying<br />Need for large volumes of flushing water<br />Only suitable where flush toilets are used<br />Advantages & Disadvantages<br /><br />
  79. 79. 6. SulabhShauchalaya<br />A low cost, water seal type of latrine connected to a 3’x3’x3’ pit. It is a modified handflush latrine with a specially designed pan and trap – needs very little water for flushing.<br />Sulabh International, an NGO, maintains Sulabh Community Latrines – ‘pay-and-use system – in many parts of India.<br /><br />
  80. 80. 7. Chemical closet<br />It consists of a metal tank containing a disinfectant fluid (Formaldehyde). A seat with cover is placed directly over the tank.<br />Water should not be thrown into the tank.<br /><br />
  81. 81. 8. Biogas Plant<br /><br />
  82. 82. 9ai. Shallow Trench latrine<br />Poles to attach screening<br />Security screening<br />Trench depth approx. 1.5 m<br />Access path<br />Handwashing facility<br />Dug soil (for back filling)<br />Superstructure<br /><br />
  83. 83. 5 m<br />4 m<br />Approx. 300mm<br />1.5 m<br />Plan View<br /><br />
  84. 84. 9aii. Deep Trench latrine<br />Superstructure<br /><br />
  85. 85.<br />
  86. 86. 9b. Bore Hole Latrine<br />Introduced in India by Rockefeller Foundation in 1930’s as a component of hookworm control programme.<br />Consists of a circular hole dug by an equipment called “auger”.<br /><br />
  87. 87. 20 feet<br />16 inches<br /><br />
  88. 88.<br />
  89. 89. Just pay attention to the lecture. The slides can be downloaded from<br /><br />
  90. 90. WATER CARRIAGE SYSTEM<br /><br />
  91. 91. The Water Carriage System or Sewerage System implies collecting and transporting of human excreta and wastewater from residential, commercial and industrial areas, by a network of underground pipes called “SEWERS” to the place of ultimate disposal.<br /><br />
  92. 92. Elements of a Water Carriage System<br /><ul><li>Household sanitary Fittings</li></ul>House drain<br />Public Sewer<br />Sewer Appurtenances<br />Manholes<br />For inspection, repairs and cleaning<br />Traps<br />To prevent foul gases entering the houses.<br />Water Closet<br /><ul><li>Indian Squatting type
  93. 93. Western Commode type</li></ul><br />
  94. 94. SEWAGE<br /><br />
  95. 95. “SEWAGE” is wastewater from a community containing solid and liquid excreta<br />“SULLAGE” is wastewater which does not contain human excreta<br />“DRY WEATHER FLOW” is the average amount of sewage that flows through the sewerage system in 24 hours<br /><br />
  96. 96. Strength of Sewage<br />BOD (Biochemical Oxygen Demand)<br />COD (Chemical Oxygen Demand)<br />Suspended Solids<br /><br />
  97. 97. BOD<br />Amount of oxygen absorbed by a sample of sewage during a period of 5 days at 20°C.<br />BOD≥ 300 mg/L – Strong Sewage<br />BOD< 100 mg/L – Weak Sewage<br /><br />
  98. 98. COD<br />The amount of oxygen (in mg) required for the complete chemical oxidation of organic and inorganic material in 1 litre of an effluent<br />The result of a chemical oxygen demand test indicates the amount of water-dissolved oxygen consumed by the contaminants, during two hours of decomposition from a solution of boiling potassium dichromate.<br /><br />
  99. 99. SUSPENDED SOLIDS<br /><100 mg/L – Weak Sewage<br />>500 mg/L – Strong Sewage<br /><br />
  100. 100. MODERN SEWAGE TREATMENT<br /><br />
  101. 101. SLUDGE DIGESTER<br />Or<br />Compost etc.<br />SLUDGE<br />GRIT REMOVAL<br />SCREENING<br />PRIMARY SEDIMENTATION<br />REMOVAL OF BULKY SOLIDS<br />REMOVAL OF DENSE SOLIDS<br />SEDIMENTATION OF SUSPENDED MATTER<br />Basic Treatment … Primary stage<br /><br />
  104. 104. SLUDGE DIGESTER<br />Or<br />Compost etc.<br />EFFLUENT <br />To Disposal by:<br /><ul><li>Dilution
  105. 105. To Land for Irrigation</li></ul>SLUDGE<br /><br />
  106. 106.<br />
  107. 107. OTHER METHODS OF SEWAGE DISPOSAL<br /><br />
  108. 108. Sea outfall<br />River outfall<br />Sewage Farming/Broad Irrigation<br />Waste Stabilization Pond/Oxidation Pond<br />Oxidation ditches<br />Aerated Lagoons<br /><br />
  109. 109. Sewage farming/Broad Irrigation<br />Sewage is applied to land after screening, grit removal and a short period of settlement.<br /><br />
  110. 110. Waste Stabilization Pond / Oxidation Pond<br />Other names: Redox pond, Sewage lagoon<br />Open shallow pond, 1-1.5m deep, with an inlet and an outlet<br /><br />
  111. 111. Oxygen<br />Algae<br />CO2<br />O2<br />Aerobic<br />Bacteria<br />Bacteria<br />Solids Settled<br />Anaerobic<br /><br />
  112. 112. Thank You<br /><br />