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Etp 2011 -slide share

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