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Etp 2011 -slide share

  1. 1. Design of Water and Waste Water Management System<br />Er.j.n.sharma<br />
  2. 2. Water and waste water management<br /><ul><li>Introduction
  3. 3. Evolution of Wastewater system
  4. 4. Treatment Process fudamentals
  5. 5. Objectives (Regulatory requirement)
  6. 6. Treatment Process selections
  7. 7. Different Treatment Technologies
  8. 8. Design of Waste water Treatment System
  9. 9. Waste minimisation and pollution prevention</li></li></ul><li>WATER SCENARIO<br /><ul><li> From a satellite image, the planet earth looks like a blue pearl --- more than 70 percent of the planet is composed of water.
  10. 10. Ironically, only 2.5 % of the world’s water is fresh, with a mere 0.3 % available from rivers, lakes and reservoirs
  11. 11. Unfortunately, the number of people with access to clean water for drinking and sanitation is decreasing rapidly due to a number of factors
  12. 12. Each year, roughly 450 cubic kilometres of waste water is discharged into rivers, streams and lakes
  13. 13. According to a development report by the United Nations, every human being needs to consume 20-50 litres of freshwater, free of contaminants, each day.
  14. 14. By 2025, there will be 48 countries and by 2050 there will be at least 54 countries facing this phenomenon Water Stress. </li></li></ul><li>INTRODUCTION<br /><ul><li>Economic growth in most of the world has been so vigorous that nearly all new development activity creates stress on the “Pollution carrying capacity" of the environment.
  15. 15. Many hydrological systems in developing regions are, or are getting close to, being stressed beyond repair.
  16. 16. Industrial pollution, uncontrolled domestic discharges from urban areas, diffuse pollution from agriculture and livestock rearing, and various alterations in land use or hydro infrastructure may all contribute to non-sustainable use of water resources, eventually leading to negative impacts on the economic development of many countries or even continents.
  17. 17. Lowering of groundwater tables , irreversible pollution of surface water and associated changes in public and environmental health are typical manifestations of this kind of development.</li></li></ul><li><ul><li>Technology, particularly in terms of performance and available waste-water treatment options, has developed in parallel with economic growth.
  18. 18. However, technology cannot be expected to solve each pollution problem.
  19. 19. Typically, a Wastewater treatment plant transfers 1 m3 of wastewater into 1-2 litres of concentrated sludge.
  20. 20. Wastewater treatment systems are generally capital-intensive and require expensive, specialised operators</li></li></ul><li>Evolution of Wastewater system<br />
  21. 21.
  22. 22.
  23. 23.
  24. 24. Objective<br /><ul><li> To protect public health
  25. 25. To protect receiving environment f rom degradation or contamination
  26. 26. To meet the regulatory requirements and discharge standards---mainly </li></ul> Foul odour, Grit, Floating matter,<br /> Suspended Solids (TSS),Soluble organics (BOD),<br />Nitogen (TKN, Ammonia), Phosphorus (TP), Bacteria, Pathogens, Virus<br /><ul><li> To reduce costs of treatment by retaining water and solids near their point of origin through reuse or recycle</li></li></ul><li>Treatment Process Fudamentals<br /><ul><li>Physical process (sedimentation, screening, membrane etc)
  27. 27. PRIMARILY PRELIMINARY TREATMENT PROCESS
  28. 28. Chemical process (coagulation, neutralization etc)
  29. 29. MAINLY PRIMARY TREATMENT PROCESS
  30. 30. Biological process (activated sludge, biofilm)
  31. 31. MAINLY SECONDARY TREATMENT PROCESS
  32. 32. --- AEROBIC
  33. 33. ANERO BIC
  34. 34. FACULTATIVE
  35. 35. Hybrid (wetland, MBR etc)
  36. 36. AUXILIARY/TERTIARY TREATMENT PROCESS</li></li></ul><li>Aerobic Treatment Systems<br />Aerobic Lagoons<br />Aerated Lagoons<br />Oxidation Ditches<br />Activated Sludge<br />SBRs – Sequencing BatchReactors<br />Trickling Filters<br />Fixed Media Biofilters<br />Rotating BiologicalContactors<br />Reciprocating Wetlands<br />Constructed Wetlands<br />
  37. 37. MOST COMMONLY USED BIOLOGICAL PROCESSES  <br /><ul><li> ACTIVATED – SLUDGE PROCESS /extended aeration(for large installations)
  38. 38. AERATED LAGOON
  39. 39. TRICKLING FILTERS
  40. 40. ROTATING BIOLOGICAL CONTRACTORS
  41. 41. STABILISATION PONDS (for smaller installations)</li></ul>Advanced<br /><ul><li>SEQUENCING BATCH REACTOR (SBR)
  42. 42. MOVING BED BIOLOGICAL REACTOR (MBBR)
  43. 43. MEMBRANE BIO-REACTOR (MBR)</li></li></ul><li>Basic Biological reaction<br /><ul><li>Processes :
  44. 44. Oxidation
  45. 45. Respiration
  46. 46. Synthesis
  47. 47. Products :
  48. 48. Water
  49. 49. CO2
  50. 50. NH3
  51. 51. Additional microorganisms</li></ul>In any biological treatment system there will be an accumulation of<br /> microbial and non-biodegradable solids that need to be managed and disposed properly<br />
  52. 52. Typical Aerobic TreatmentSystem<br />
  53. 53. Performance<br /><ul><li>Odor:
  54. 54. 2 to 6 days: 50 – 90%
  55. 55. Organic matter:
  56. 56. 5 to 7 days: over 95%
  57. 57. Nitrogen:
  58. 58. Intermittent aeration, 7 days min: 80 – 95%
  59. 59. Phosphorus:
  60. 60. Intermittent aeration, 7 days min: 70 – 80%
  61. 61. Bacterial indicators:
  62. 62. 5 to 7 days: 1 to 3 log units</li></li></ul><li>Other benefits<br />No odor regeneration was discerned over the<br />first 28 days after storage of aerobically<br />treated manure (2.4 days).<br />Aerobic treatment can reduce odor<br />emissions from land spreading operations up<br />to 90%.<br />
  63. 63. Activated Sludge with Solids Prescreening<br /><ul><li>Proven technology for municipal and industrial wastewater
  64. 64. Requires proper design and trained Operators
  65. 65. Is energy intensive</li></li></ul><li> DESIGN CONSIDERATIONS :<br /><ul><li> INTERNAL FACTORS
  66. 66. Selection of Reactor types,
  67. 67. Process variations
  68. 68. Technology know-how
  69. 69. EXTERNAL FACTORS
  70. 70. Construction cost
  71. 71. Operation and maintenance difficulties & cost
  72. 72. Space limitations (sizing of units and treatment system)</li></ul>Activated sludge systems<br />
  73. 73. MAJOR DESIGN PARAMETERS<br /> SEDIMENTATION TANK (OFR V/S % REMOVAL) <br /><ul><li>Hydraulic loading, (WATER BUDGET , SHIFTS) Hydraulic retention time (HRT), 2—2.5hrs</li></ul>BIOREACTOR<br /><ul><li> Organic Loading,
  74. 74. Effluents characteristics,
  75. 75. Solid retention time (SRT),
  76. 76. Organic loading rate (ORT),
  77. 77. Food to microrganism ratio (F/M),
  78. 78. Mean Cell residence time ( 0c),
  79. 79. Aeration period,
  80. 80. Sludge production-----(rate of return sludge & excess sludge wasting ),
  81. 81. O2 Requirements & transfer,
  82. 82. Nutrient requirements, (12.4% by wt.of nitrogen & 20% of this value is for Phosphrous),
  83. 83. Control of filamentous organisms,
  84. 84. (Settleability test, Sludge volume index, SVI)
  85. 85. Parameters to be achieved</li></li></ul><li>HYDRAULIC RETENTION TIME (HRT)<br /> HRT = VOLUME/ FLOW RATE (V/Q)<br />THE RESIDENCE TIME FOR THE LIQUID FRACTION IN THE BIO – REACTOR<br />SOLID RETENTION TIME (SRT)<br />SRT=<br />THE RATIO OF AMOUNT OF BIOMASS WITHIN THE SYSTEM TO THE GROWTH RATE OF NEW MICROORGANISM<br /><ul><li>LONGER SRT RESULTS ( 20-30 days)
  86. 86. IN MORE EFFICENT BIODEGRATION,
  87. 87. SMALLER REACTOR SIZE ,
  88. 88. ECONOMICAL IN COST
  89. 89. HIGHER SRT CLARIFIER FAILURE</li></li></ul><li>Biological Kinetics Equations,<br /> 0C.QY(S0—S)<br /> V = _______________ , <br /> X(1+kd.0c)<br />where V = Volume of the reactor,<br />S0 = Influent Soluble BOD5,<br />S = Effluent Soluble BOD5,<br /> Q = Influent wastewater flow rate,m3/D0c<br />0c = Mean Cell residence time based on solids,(d),adopted for<br /> design controls quality, Settleability & drainability of Biomass,<br />O2 requirement & quantity of waste activated sludge.<br />kd = ENDOGENOUS DECAY COEFFICENT,d-1 (0.06/d) for Municipal waste wter<br /> Y =Yield Coefficent over finite period of log growth, g/g (0.5)<br /> X = MLSS, Conc., mg/l<br /> The volume of the aeration tank is calculated for the selected value of 0c<br /> by assuming a suitable value of MLSS Conc<br />
  90. 90. OR,<br /> ALTERNATIVELY, the tank capacity may be designed <br /> from the F/M & MLSS Conc.<br />F/M = Q S0 / XV<br />
  91. 91. SLUDGE RECYCLE :<br /><ul><li>THE MLSS CONC. IN THE AERATION TANK IS CONTROLLED </li></ul>BY THE SLUDGE RECIRCULATION RATE & THE SLUDGE SETTLEABILITY <br />AND THE THICKENING IN THE SECONDARY SEDIMENTATION TANK.<br /><ul><li>THE SLUDGE SETTLEABILITY IS DETERMINED BY THE SLUDGEVOLUME INDEX (SVI)</li></ul> IS DEFINED AS THE VOL. in mm OCCUPIED BY 1 gm OF A ACTIVATED SLUDGE MIXD LIQUER <br />SOLIDS ( dry wt.) AFTER SETTLING FOR 30m IN 1000 ml GRADUATED CYLINDER.<br />
  92. 92. TYPICAL SUSPNDED SOLIDS MASS BALANCE FOR RETURN SLUDGE CONTROL<br />S<br />AERATION TANK SECONDARY CLARIFIER<br />Q S0 X0 V Q+Qr<br /> X<br />____________________________________________________________________________ QeXe<br />Qr, Xr Q*w,Xr<br />Schematic Diagram of Activated-Sludge Process<br /> the Mass balance around the settling tank is as follows :--<br />Accumulation = Inflow -- Out flow<br /> = X ( Q + Qr) - Qr.Xr- Xr Q*w ,<br />Qr = XQ –XrQ*w<br />Xr - X<br />
  93. 93. LATEST BIOLOGICAL TREATMENTS<br />Fixed media attached growth Process<br />
  94. 94. Membrane Bioreactors<br />•Suspended growth – similar to activated sludge<br />•Two parts – biological unit and membrane filter<br />•High effluent quality BOD<5 mg/L, TSS<5 mg/L<br />•Greater potential for removal of endocrine disruptingchemicals, pharmaceuticals, <br />
  95. 95. Activated Sludge / Extended Aeration<br />EXTENDED AERATION <br /><ul><li>Long detention time and low F/M ratio in aerator to maintain culture in endogenous phase</li></ul>• Can accept intermittent loading without upsetting system<br />• Potential for filamentous<br /> bacteria – makes settling difficult<br />
  96. 96. Moving Bed Bioreactors (HYBRID) <br /> (Suspended + Fixed Biological Process)<br /><ul><li>Ring-type plastic media to support Bio-mass
  97. 97. Polythelene with density les than water but almost same as aerated water
  98. 98. Very High Surface Area (>300m2/m3)
  99. 99. 30% to 50% reactor filled with media
  100. 100. Coarse bubble aeration</li></ul>Attached growth aeration process with some suspended growth as well<br /><ul><li>ADVANTAGECompactness, Process Simplicity Biomass stability Best for Retrofit/ upgradtation of Existing plant Roughing or Polishing Trratment for Strong Industrial Plant</li></li></ul><li>Suspended Growth Process<br />- The Sequential Batch Reactor (SBR)<br />
  101. 101. Sequencing Batch Reactor (SBR)<br />Cyclic processes of fill, react, settle,<br />effluent removal, and idle are controlled<br />by time to achieve objectives.<br />Short aerating/non-aerating periods at a<br />HRT = 10 days resulted in removals of<br />COD (93%), SS (98%), and all NH3<br />converted to NO3.<br />
  102. 102. Sequencing Batch Reactor (SBR)<br />• Type of activated<br />sludge process<br />• Five steps<br />• Fill<br />• React (aeration)<br />• Settle<br />• Draw (decant)<br />• Idle<br />•Example – Duke<br />
  103. 103.
  104. 104. Rotating Biological Contactors<br />•Aerobic system<br />•Series of closely spaced circular disks rotate -submerged in wastewater<br />•Reliable - withstand hydraulic and organic surges<br />•Low energy costs<br />•Potential mechanical failure<br />
  105. 105. Factors<br /><ul><li>Residence time:
  106. 106. Hydraulic: 5 to 7 days
  107. 107. Solids: 15 to 30 days
  108. 108. Aeration type:
  109. 109. Continuous
  110. 110. Intermittent
  111. 111. Aeration level:
  112. 112. Low level: between 0 and 1 mg/L
  113. 113. High level: 2 to 4 mg/L</li></li></ul><li>Aerobic Lagoon <br />
  114. 114. Facultative lagoon<br />
  115. 115. Oxidation Ditch<br />
  116. 116. Amount of oxygen<br />Removal of odor<br />Oxygen demand = 1/2 to 1/3 BOD<br />Removal of organic matter<br />Oxygen demand = BOD<br />Removal of nutrients<br />Oxygen demand = BOD + NH3-N<br />
  117. 117. Complete Aeration<br /><ul><li>Complete aerobic treatment eliminates odors and undesirable gases.
  118. 118. Floating aerators provide continuous aeration.
  119. 119. Aeration requires large amounts of energy.</li></li></ul><li>Large Aerator Compressor<br /><ul><li>Large compressors</li></ul> are used to provide complete aeration.<br /><ul><li>Oxygen transfer</li></ul> rates of 3 lb O2/hphr are normally used.<br /><ul><li>A 1- hp aerator should serve approximately 144 finishing hogs.</li></li></ul><li>Partial Aeration<br /><ul><li>Partial aeration can</li></ul>reduce odors and<br />gases, although it may<br />actually increase odors<br />if under designed.<br /><ul><li>Floating aerators may</li></ul>be used for partial<br />aeration. The number<br />of units determines the<br />completeness of the<br />aeration.<br />
  120. 120. Types of aerators<br /><ul><li>Surface mechanical aerators
  121. 121. Diffusers</li></ul>Pay attention to:<br /><ul><li>Energy – 0.05 to 0.10</li></ul> (kWh/gal)<br /><ul><li>Oxygen transfer efficiency</li></ul> (lb O2/kWh)<br /><ul><li>Reliability (wear, corrosion,</li></ul> etc.)<br />
  122. 122. Diffusers<br />
  123. 123. Surface Aerators<br />
  124. 124. Aerator Design<br />
  125. 125. Aerator Design<br />
  126. 126. Calculating HP Requirement<br />
  127. 127. Types of Aerobic treatmentsystems<br />Types of aerobic treatment<br /> systems<br /><ul><li>Fed-batch or semi</li></ul>-- continuous<br /><ul><li> Continuous system</li></ul>Activated sludge<br /> Aerated lagoons<br /> Aerated filters<br /><ul><li>Composting</li></li></ul><li> thanks<br />

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