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Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
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Final Comprehensive Examination
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Final Comprehensive Examination
Final Comprehensive Examination
Final Comprehensive Examination
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Final Comprehensive Examination

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complete layout of course design in Masters program :)

complete layout of course design in Masters program :)

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  • Need to explain in brief about the various properties of air.
  • Transcript

    • 1. DEEPAK LEO JOHN
    • 2. CE 5328
    • 3. INTRODUCTION
      • Air Pollution : The presence in external atmosphere of one or more contaminants/pollutants/combination that may induce harmful effects on humans/living being’s health.
      • Types of Pollutants
      • Primary Pollutants : Directly emitted from source
      • Secondary Pollutants : Not emitted dirctly but are formed in the atmosphere by chemical reactions
      • Sources
      • Point / Stationary
      • Area / Mobile
    • 4. Structure of Atmosphere
      • Atmosphere is divided into layers based on the thermal structure
      • Troposphere, Stratosphere, Mesosphere and Thermosphere.
      • Troposhere is where the weather changes happen and the pollutants are emitted, mixed, dispersed and transported.
      • Stratosphere contains the protective ozone layer.
      • Troposphere + Stratosphere accounts for 99.9% of earth’s atmospheric mass
      • Fig : Structure of atmosphere (http://www.kowoma.de/en/gps/additional/atmosphere.htm)
    • 5. Properties of Air
      • Composition of air
      • Molecular weight of air
      • Viscosity
      • Reynolds Number
      • Ideal Gas Law (PV=nRT)
      • Concentration Measurements
    • 6. Types of Air Pollutants
      • Primary Air Pollutants
      • Particulates
      • Sulfur Dioxide
      • Carbon Monoxide
      • Lead
      • VOC’s
      • Nitrogen Oxides
      • CFC’s
      • Greenhouse gases
      • Secondary Air Pollutants
      • Ozone
      • Particulates
      • Various sources of the pollutants and the effects of the pollutants were discussed.
    • 7. Clean Air Act
      • Federal standards to protect public health
      • NAAQS : National Ambient Air Quality Standards
      • Two Kinds
      • Primary : protects public health (people)
      • Secondary : protects public welfare (buildings, crops etc.,)
      • Set of 6 criteria Pollutants : SO 2 , No x , CO, O 3 , PM and Pb.
      • However VOC’s are not included, but are regulated indirectly through ozone levels.
      • NAAQS says about an area meeting attainment or non-attainment.
      • A state must submit plans to EPA telling how it is going to comply with NAAQS  State Implementation Plan (SIP).
      • New sources or major modifications of existing sources must obtain a New Source Review (NSR) / Construction Permit.
      • NSR Permit  2 types
      • Attainment Areas : PSD permits (BACT, modelling)
      • Non-Attainment Areas : Non-Attainment New Sorce Review (NNSR) (LAER, offsets)
      • NSR Permits and SIP work hand-in-hand to achieve NAAQS standards.
    • 8. Clean Air Act
      • Fedreal Operating Permits (Title V)
      • Acid Rain Permits
      • Hazardous Air Pollutant Standards (MACT/NESHAPs)
      • Emission Inventory to know of a source is major.
      • Common testing methods for estimating emissions are emisson factors (AP-42) and Source Testing.
    • 9. Gas Flow Measurement
      • Continuity Equation : Conservation of mass
      • Bernoulli’s Equation : Conservation of Energy
      • Measuring Pressure difference using a manometer ( Pressure differences are important in measuring volumetric flow rates)
      • Measuring Volumetric flow rate using Venturimeter, Orifice meter & Rotameter.
      • Measuring the Velocity - Pitot tube
      • Measuring Wind Speed & Direction – Anemometer, wind sack/vane
    • 10. Sampling and Monitoring
      • Sampling  intermittent
      • Monitoring  continious
      • Determine
      • Amount of emission permitting, inventories
      • Efficiency of control equipment
      • Compilance with regulations
      • Sample Collection – Gases  Absorption, Adsorption, Organic traps and Whole air sampling.
      • Sample collection – Particulates  Inertial collection (cyclones), Filtration.
      • Onboard System for Vehicle Emission Measurement.
    • 11. Control Technologies
      • Gas control Technologies
        • Incineration
        • Adsorption
        • Absorption
        • Biological control
      • Particulate control Technologies
        • Electrostatic prcipitators
        • Fabric Filters
        • Particulate scrubbers
    • 12. CE - 5320
    • 13. Solid Waste Hierarchy
      • Solid waste is useless, unused unwanted or discarded material in solid form that includes semi solid food waste and municipal sludge
      • Solid waste in technical aspect is garbage, refuse, sludge from WWTP/WTP, including solid, liquid or semi-solid
      • Hierarchy of Solid Waste Management
        • Source Reduction in source
        • Recycling
        • Waste Transformation
        • Landfilling
    • 14. Sources, Types & Composition of MSW
      • Sources
        • Treatment plant sludge
        • Light Industrial Waste
        • Mixed waste (residential & commercial)
      • Types
        • Residential / Commercial
        • Institutional
        • Construction and demolition
        • Industrial
      • Composition depends on relative properties of sources, activity in town, living standards and economy
      • Physical composition can include paper, plastic, glass, metals food waste etc.,
    • 15. Properties of MSW
      • Physical Properties
        • Specific weight
        • Moisture Content
        • Particle size & size distribution
        • Field capacity
        • Degree of compaction
        • Permeability of compacted MSW
      • Chemical Properties
        • Proximate Analysis
        • Fusing point of Ash
        • Ultimate Analysis
        • Energy conent of MSW
      • Biological Properties
        • Biodegradability
        • Odor
        • Breeding of flies
    • 16. Municipal Solid Waste
      • Waste Generation (Quantitative)
        • Load count analysis – recording the no. of individual loads
        • Weight Volume analysis – directly measuring weight and volume of each load
      • Waste Handling
        • Seperation of wastes
        • Collection and Routing of MSW
        • Transfer Stations – a link between community collection and final disposal facility
    • 17. Sanitary Landfill
      • Operational Steps
        • Unload
        • Spread
        • Compact
        • Cover
      • Basic components of Sanitary Landfill
        • Cell
        • Cover layer system
        • Gas control & recovery system
        • Leachate collection system
        • Gas monitoring probes
        • Ground water monitoring wells
    • 18. Sanitary Landfill
      • Design of Landfill
        • Develop preliminary site plan of fill area
        • Compute the solid waste sorage volume, soil requirement volumes & site life
        • Prepare construction details for leachate collection and treatment, landfill gas control systems, surface water control system, strom water runoff system access roads and monitoring wells
        • Prepare cost estimates
        • Prepare environmental impact assesment
        • Prepare plans for closure and post closure care.
    • 19. CIRP 5357
    • 20. Fundamentals of GIS concepts
      • Two types of data to describe geographic features
        • Spatial data
          • Describes the location/coordinates (latitude, longitude)
        • Attribute data
          • Specifies characteristics of the location
          • Stored in a database and understood in a tabular form.
      • Spatial and attribute data are maintained seperately and then joined or linked for display and analysis
      • Spatial Data types
        • Bounded area, continious area, networks and points.
      • Spatial data is organized by layers, with each layer representing a common feature.
    • 21. Fundamentals of GIS concepts
      • Attribute data types
        • Categorical(character field) and Numerical(integer, floating point, decimal)
      • Data are grouped into Vector and Raster data models
      • Vector data model
        • Location referenced by x,y coordinates, which can be linked to form lines and polygons
        • Attributes referenced through unique id number to tables
        • Best used for layers with disrete boundaries
      • Raster data model (requires spatial analyst models)
        • Location is referenced by a grid cell in a rectangular array
        • Attributes reffernced through a single value for the cell
        • Best used for continious layes.
    • 22. ArcGIS Components
      • ArcCatalog
        • For organizing and managing GIS data
          • Browse
          • Search
          • Define
          • Metdata
      • ArcMap
        • Cental Application
          • Cartography
          • Analysis
          • Editing
      • ArcToolbox
        • Standalone Geoprocessing Tools
          • Analysis
          • Conversion
          • Batch Processing
    • 23. Query, Analysis and Modeling
      • Basic Spatial Opreation
        • Spatial Measurement
          • Distance
          • Area
          • Centroid
        • Spatial Aggregation
          • Redistricting
          • Classification
        • Spatial Overlays and joins
          • Spatial selection
          • Spatial assignment
          • Clipping
          • Erasing
          • Merging
      • Buffer analysis
      • Geocoding
      • Attribute operations
        • Record selection
        • Variable recoding
        • Record aggregation
        • General statistical analysis
    • 24. Data Format Conversion
      • Vector to Raster : point
        • Node x,y is assigned to closest raster cell
        • Location shift almost inevitable, error depends on raster size
        • Two points in one cell cannot be identified
        • Cannot be converted back without error
      • Vector to Raster : line
        • Cells assigned if touched by line
        • Brightness of line varied based on fraction cell covered by the line
      • Raster to Vector ( 3 step process)
        • Reduce rasters to unit width by decreasing the pixels
        • Vector extraction – to identify the lines
        • Topological reconstruction – recreates topological structures
    • 25. PHYSICAL CHEMICAL PROCESSES Ι CE – 5318
    • 26. Stiochiometery & Batch Reactor Kinetics
      • Stiochiometery tells how much one chemical reacts with another to form how much of a product
      • Stoichiometric co-eff of reactant –ve (disappearing)
      • Stoichiometric co-eff of product +ve (appearing)
      • Reaction Kinetics tells how fast a reaction is occurring
      • Classes of reaction:
        • Homogeneous : single phase  reaction
        • Hetrogeneous : reaction occurs between different phases  reaction and transport
      • Mass Balance:
          • Accumulation = Inflow – Outflow + Generation
      • Batch Reactor:
        • No inflow or outflow
        • Time is zero when reactants are added and mixed together
        • Primary use  to determine the rate and order of the reaction
        • Possible because rate of accumulation term is equal to rate of reaction
    • 27. Complete Mix and Plug Flow Reactor
      • They are continuous type reactor
      • Plug Flow reactor
        • Completely mixed laterally
        • No mixing longitudinally
        • The response of a PFR as a fn of θ H at steady state is the same as the response of a batch reactor
      • Complete Mix Reactor
        • Perfectly mixed and hence the properties are uniform at any given time because of stirring
      • CFSTR in series
        • Output of the first reactor will be input to the second reactor
      • Plug Flow with axial dispersion
        • D/uL  dispersion number  ∞  complete mixing
        • dispersion number  0  ideal plug flow
      • PFR & CFSTR with recycle
    • 28. Hetrogeneous System
      • Hetrogeneous : reaction occurs between different phases  reaction and transport
      • Mechanism of Substrate removal
        • Transport of substrate from bulk fluid to the biofilm-water interface
        • Transport of substrate into biofilm
        • Reaction in biofilm
        • Transport of products out of biofilm
        • Transport of product from biofilm water interface to bulk fluid
      • Reaction rate vs Transport Limited
        • Reaction rate limited when shallow
        • Transport rate limited when steep
    • 29. Lake Classification
      • Lakes are classified by
        • Method of origin
        • How often lakes undergo thermal stratification and destratification
        • Trophic level
      • Trophic level clasification
        • Photosynthetic growth levels called primary production
        • Nutrient concentration
        • Measurement of biodiversity
      • Modelling of Water Quality in lakes
        • Hydraulic Modelling
          • Detention times can be very large and mixing present hence much closer to CFSTR than PFR
          • Water movement largely a function of wind / thermal mixing. Mixing difficult to model
          • Seasonal Variation intemprature results in stratification
    • 30. Lake Classification
        • Water Quality
          • Most lakes and reservoirs are aerobic, epiliminion
          • Nutrient levels are not static because of complex ecosystem
          • Undesirable lake water quality is most often associated with high algae concentration.
      • Modelling of hydrodynamic conditions and also the ecosystem of the lake is difficult and can be very complex
      • A complete model can be obtained when combining both hydrodynamic condition and ecosystem
      • River Model (Streeter Phelps equation)
        • Considers the river as a PFR
        • Equation describes DO sag as a fn of θ H
        • Actually calculates the defecit of oxygen
        • Hence can calculate DO at any point of the river
    • 31. Mixing and Flocculation
      • Perfectly mixed  CFSTR  Homogenity at all locations in the reactor
      • Mixing is a fuction of turbulence
      • Turbulence is a result of irregular flow conditions
      • The intensity of turbulence can be expressed as a fraction of time average velocity
      • Eddies are important for flocculation
      • Particles smaller than eddies will move together and not colloide
      • Large eddies arise from the interaction of mean flow with the boundaries
      • They carry most of the mixing energy
      • Under turbulent conditions without flow, the transfer of mass is brought about my microscale turbulence known as turbulent or eddy diffusion
      • Eddy diffusion and dispersion depends primarily on the flow regime
    • 32. Mixing and Flocculation
      • Perikinetic (micro floc) Flocculation:
        • The aggregation of particles brought about by the random thermal motion of fluid molecules also know as Brownian Motion
        • Significant for particles in the range of 0.001 – 1.0 μ m
      • Orthokinetic (Macrofloc) Flocculation :
        • Aggregation of particles greater than 1-2 μ m
        • Can be brought about by induced velocity gradient and differential settling
    • 33. Sedimentation
      • Types of sedimentation : depends on conc of suspension& characteristics of particles
        • Discrete Settling :
          • Particles settle independent of each other.
          • Flow capacity is is independent of depth
          • A particle will accelerate until it reaches terminal velocity
        • Flocculant particle Settling:
          • Particles in relatively dilute solutions will not act as discrete particles but will colaesce during sedimentation
          • As Colascence or flocculation occurs, the mass of the particle increases and it settles faster
    • 34. Sedimentation
        • Hindered (Zone) Settling:
          • Because of the high concentration of particles the liquid tends to move up through the gaps of the contacting particles
          • As a result the contacting particles settle as a blanket or zone maintaining the same relative position with respect to each other.
        • Compression Settling:
          • Occurs when particles settle by compressing the mass below
          • Stirring serves to compact solids in the compression region by breaking up flocs & permitting water to escape.
          • Heavy concentration of solids
    • 35. Filtration
      • Characteristics
        • Filtration used for removal of suspended and colloidal particles
        • Porous media captures solids and transports water
        • Filtration is a primary physical process but chemicals can be added to improve performance
        • Two phase process : solids removals during filtration followed solids removal in backwashing
        • Filtration is typically non continious process because it has two phases
      • The effective size of filtering medium
        • It is the 10% size based on mass
        • Uniformity co-efficient Uc is d 60 /d 10
        • d 10 is used in selecting filter medium
        • Indicator of performance & Low d 10 produce better quality
    • 36. Gas Transfer
      • Gas transfer is a hetrogeneous system
      • Two Film Theory
        • Based on a physical model in which two film exist at the gas liquid interface
        • There are 2 conditions
          • Adsorption in which gas is transferred from the gas phase to liquid phase
          • Desorption in which gas is transferred out of the liquid phase into the gas phase
        • The two film theory provides the resistance to the passage of gas molecules between the bulk gaseous phase
      • Oxygen transfer rate OTR
      • Standard Oxygen transfer rate SOTR
    • 37. TRANSPORTATION & AIR QUALITY CE - 5324
    • 38. The Mobile Source Problem
      • Trends of vehicle ownership
      • The upside and the downside of automobiles
      • Trends of on road transportation source emission
      • Trends of off road emissions
      • Air pollution in developing countries
    • 39. Internal Combustion Engines
      • Pollutants that result from combustion
        • Oxides of Nitrogen
        • Oxides of Sulfur
        • Particulates
        • CO
      • Otto cylce (4 stroke)
        • Intake stroke
        • Compression stroke
        • Power stroke
        • Exhaust stroke
      • Air to fuel ratio influneces the pollutant production
      • Evaporative emmisions
      • 2 stroke gasoline engines
    • 40. Clean Air Act Provisions
      • Clean air act direct provisions
      • Clean air act SIP provisions
      • Conformity
        • CAA requires confirmity that highway and transportation projects conform to the purpose of SIP
      • Fuel economy standards
        • Corprate average fuel economy (CAFÉ)
        • Cars  27.5 mpg
      • California’s Low Emission Vehicle(LEV) program
    • 41. Estimating Emissions
      • SIP requires quatitative estimates of emission reductions
      • To ensure controls are sufficient to bring the region into compilance
      • Emmisions = Emission Factor x VMT
      • Macro scale emission model  Emission Factor (Mobile6)
        • Mobile6 calculates basic emission rates  adjusts the emission rate based on temprature, air conditioning, humidity, gasoline content, inspection & maintainence program
      • Travel Demand Model  VMT
        • Estimates the amount of transportation activity occuring in a region
        • Typical outputs : No. of transit trips, automobile occupancy, average vehicle speed for each roadway segment, VMT
    • 42. Ambient Concentration Modelling
      • Dispersion Modelling
        • uses output from emission model as input
        • Accounts metereology to predict atmospheric concentration
        • Simulates what happens to the pollutants emitted into the atmosphere
        • 3-D analysis system
        • Assumes double gaussian distribution (double bell shaped curve)
    • 43. Engine Design Changes
      • Avoiding Stiochiometric combustion (lower NOx)
        • Air-to-fuel ratio
        • Stratified charge engine
        • Extra lean burn engine
      • Lowering Combustion Temprature
        • Exhaust gas recirculation
        • Water injection
        • Changing engine cycle – Diesel
        • Fuel Injection system modifications
    • 44. Alternate Fuels
      • Natural gas, propane, methanol, ethanol and biodiesel
      • Reformulated gasoline
      • Hybrids
      • Fuel cells, hydrogen
      • Add on tailpipe emission control
        • Catalytic converters
        • On board vapour recovery system
    • 45. Transportation System Management (TSM)
      • Reducing emissions due to vehicle operations
      • Improve traffic flow by better management of existing transportation facilities
      • Cheaper than capital improvements
      • Travel time is decreased (mobility increased)
      • Good management can increase roadway capacity by 30%
      • TSM Measures
        • Speed Limit Reduction
        • Intelligent transportation system
        • Driver behaviour education
    • 46. AIR DISPERSION MODELLING CE - 5323
    • 47. INTRODUCTION TO AIR QUALITY MODELING
      • Air Quality Model simulates mathematically pollutants concentration between source and receptor
      • It includes Pollutants transport, dispersion ,chemical and physical removal along with the removal process
      • Thus the above factor makes it to fit into the field of air pollution
      • Types of air pollution modeling:
        • Gaussian dispersion modeling
        • Photochemical Modeling
        • Box Modeling
        • Receptor modeling
        • Statistical modeling
    • 48. REVIEW OF AIR POLLUTION METEOROLOGY
      • Causes of wind :
        • ∆ T-> ∆ ρ -> ∆P -> wind
      • Wind is an important factor as its speed and direction enables us in determining the stability condition which in turn helps us to find the concentration of the pollutant.
      • Wind speed increases with height as the frictional force due to obstruction (trees , buildings) decreases with height.
      • Wind speed at any height can be calculated from power law formula
        • U 2 = u 1 *(z2/z1) p
      • Wind speed can be calculated by anemometer
        • Cup anemometer and Hot wire anemometer.
      • Wind direction is measured using
        • Wind vane and wind sock.
      • Instrument location
        • 10 m high on a tower.
        • Avoid rooftop location.
        • Away from structures.
      • Wind rose diagram
    • 49. Turbulence /Stability
      • Types of transport
        • Advection -> Transport of pollutant with the wind (horizontal direction)
        • Dispersion ->Transport of pollutant along vertical direction
        • Diffusion -> due to molecular diffusion or Brownian motion.
      • Dispersion is due to turbulence
      • Causes of Turbulence
        • Mechanical turbulence
        • Thermal turbulence
      • Stability is an indication of atmospheric thermal turbulence
        • Stable atmosphere -> little turbulence -> less vertical mixing.
        • Unstable atmosphere -> more turbulence -> more vertical mixing.
      • Adiabatic Process
        • Movement of airparcel without gaining or losing heat.
        • Parcel rises ,expands and cools.
    • 50. Box Models
      • Box model is a simpler model
      • Mass balance is solved for one box
      • Not as accurate especially for regional scale
      • Used for
        • Indoor air quality modeling
        • Modeling lab scale experiments
    • 51. Photochemical Grid model
      • Used for regional scale
      • The atmosphere is divided into three dimensional grid that may include thousands of grid cell
      • The model moves air and pollutant into and out of cells through advection and dispersion
      • Mass balance is solved for each box at various time step
      • Concentration output of one box becomes an input to its neighboring box.
      • Inputs are
        • Emission as function of time and space
        • Meteorological information
        • Deposition estimates
        • Chemical reaction information
    • 52. GAUSSIAN DISPERSION MODELING
      • Gaussian dispersion modeling enables us to find the pollutant concentation with respect to x,y and z direction.
      • Q is emission rate and (1/U) is downwind distance.
      • Dispersion Parameters σ y and σ z are determined using
        • Pasquill-Gifford equation
        • Briggs formula
        • Wind fluctuation measurement
    • 53. Methods of determining dispersion parameters σ y and σ z
      • Based on Stability classes
      • RURAL AREAS
      • Pasquill Gifford Prairie Grass experiments.
      • Brookhaven National Lab Scheme.
      • Tennessee Valley Authority (TVA) scheme.
      • URBAN AREAS
      • St.Louis Urban disperion Schemes.
      • Putting Together (all the above)
      • BRIGGS Formulas
    • 54. Direct measurement of dispersion parameters
      • Direct measurement of Wind Fluctuations
        • More accurate than other methods
        • Measurements can be made at the specific site .
    • 55. Stack tip downwash
      • When air blows past a building, stack, or other structure, a low pressure area forms behind the structure. In the low pressure area, air recirculates in eddies.
      • HOW TO AVOID?
      • Clean Air Act recommends a safe engineering practice stack height of:
      • h s = H B + 1.5 z’.
      • H B = height of building ; hs = stack height ;
      • z’= smaller dimension of the building height or cross- wind width.
    • 56. Relaxing Assumptions
      • Vertical limits on dispersion due to
      • inversions.
      • Effects of topography.
      • Accounting for chemical reactions
      • Accounting for physical removal.
      • Adjusting averaging times.
    • 57. CE - 5325
    • 58. Fundamentals of Microbiology
      • Classification of Microorganisms
        • By carbon and energy source
          • Chemosynthetic  energy source obtained from redox reactions
          • Photosynthetic  energy obtained from sunlight
          • Heterotrophic  Carbon source obtained from organic carbon
          • Autotrophic  carbon source obtained from CO 2
        • By cell structure
          • Prokaryotic
            • Small size, single DNA molecule
          • Eukaryotic
            • Larger size, several DNA molecules
        • Method of Reproduction
          • Sexual, Asexual, Spore formation
        • Environmental conditions for Growth
          • Oxygen requirement, temperature
        • Motility: organism free moving in water or not
    • 59. Fundamentals of Microbiology
      • Catabolism :
        • The degradative phase of metabolism in which large and complex molecules are degraded to yeild smaller, simpler molecules
        • Accompanied by release of chemical energy
        • Conversion to form energy transferring molecule Adenosine triphosphate (ATP)
      • Anabolism
        • Building up or biosynthetic phase of metabolism
        • Requires input of chemical energy, provided by Atp generated during catabolism
      • Enzymes ; catalysts of biochemical reactions
        • Characteristics
          • Specific to a given reaction
          • Both intracellular and extracellular
          • Some enzymes requires cofactors
          • Most enzymes lose activity at high tempratures
    • 60. Fundamentals of Biochemistry
      • Most biological reactions are oxidation reduction reactions
      • BOD : measures DO used by microorganisms under specified conditions over specific time period
      • COD : measures the amount of organic matter that is chemically oxidized using a strong oxidant
      • TOC : Total organic Carbon  convert C  CO2 and measure
      • Yield: ratio of biomass (sludge) produced per mass of substrate removed from water.
      • Yield: depends on relative efficiencies of energy generation and utilization
    • 61. Suspended Growth Systems
      • Suspended growth of biological systems are estimated by using monod kinetics
      • Chemostat is a reactor used for continious growth of microbial cultures. It is a CFSTR.
      • Assumptions of Monod Kinetics
        • Monod Kinetics describe degradation
        • Soluble substrate
        • Single limiting substrate
        • Constant Q
        • Completely mixed system
      • Net bacterial growth rate is controlled by θ H
      • Active biomass density in the reactor depends on the inlet substrate concentration, yield and residence time
      • Effluent substrate concentration is controlled by
        • Half velocity constant (Ks)
        • Specific growth rate ( μ m)
        • Endogeneous decay (Kd)
        • Solids Retention time ( θ H )
    • 62. Suspended Growth Systems
      • Cell washout : Residence time is so low that cells wash out before any reaction occur
      • If mean cell residence time is somewhat less than the growth then there would be no growth
    • 63. Activated Sludge
      • Components of AS system
        • Aeration Basin : completely mixed aerobic reactor with aeration
        • Clarifier : cells are seperated by sedimentation
          • Removes MLSS
          • Concentrates solids to return to bioreactor
        • Solids Recycle: Return Activated Sludge: a portion of the cells are returned to the aeration basin
      • Assumptions for modelling
        • Aeration basin is a CFSTR
        • Biodegradation occurs only in the aeration basin
        • Monod Kinetics – single limiting soluble substrate
      • Key Conept : SRT > HRT
        • Low SRT  low effluent substrate concentration
        • Low HRT  small reactor volume, high throughput, system economy
    • 64. Activated Sludge
      • Plug flow reactor with recycle
        • More efficient than a CFSTR  higher influent concentration leads to higher reaction rates
        • PFR there is higher substrate and oxygen concentration in the initial or inut phase but becomes lesser as we go down
        • Does not handle shock loads as well as CFSTR
    • 65. Sludge Bulking
      • Growth of filamentous organisms
      • Enough filaments to hold floc together
      • Interferes with settling and foaming problem occurs
      • Stratergies to control filamentous organisms:
        • PFR : Organisms go through an area of reactor with high substrate concentration. Natural selection ofhigh growth rate under high substrate concentration
        • Selector : short residence time reactor with high F/M and sufficient aeration
    • 66. Trickling Filter
      • Factors affecting Trickling Filter
        • Influent cocentration : The rate at which the bacteria can remove the substrate reaches a maximum value as concentration increases
        • Substrate particle size and treatability : are limited to soluble substrate removal
        • Specific surface area and media configuration: Increase in surface area increases performance because of greater biomass as long as oxygen is not limiting
        • Hydraulic loading: Improved mass transfer but contact time is greatly reduced for a given coloumn height and also it affects the biofilm thickness
        • Effluent recycle : lowers influent concentration but decreases mass transfer resistance
        • Sludge Recirculation : should improve performance.
        • BOD loading/Aeration : BOD loading is a product of hydraulic loading and influent concentration
        • Dosing Period : Resting may improve aeration but the hydraulic and organic loading rates are instantaneously greater
    • 67. Nitrification & Denitrification
      • Nitrification : biological oxidation of ammonia  Nitrite(nitrosomonas)  Nitrate (nitrobactor)
      • Denitrification
        • Assimlatory : Reduction of nitrate/nitrite  Ammonia
        • Dissimilatory : Reduction of nitrite/Nitrate  nitrogen gas
        • Requires
          • Absence of oxygen
          • Presence of BOD
          • Presence of nitrite and nitrate
          • Presence of denitrifiers
          • Sufficient time and proper environmental conditions
    • 68. CE – 5316 Water Supply & Treatment Plant Design
    • 69. Water Quality
      • Water Quality Parameters
        • Chemical Parameters
          • Inorganic compounds (ions)
          • Organic compounds
        • Physical Parameters
          • Temprature
          • TSS
          • Turbidity
          • Color
          • Taste and Odor
        • Biological Parameters
    • 70. Major Processes
      • Screening – process to remove suspended solids through racks and screens
      • Aeration – process to increase DO concentration for taste and odor control
      • Pre-oxidations – oxidize dissolved compounds for taste and odor control, color reduction, achieving disinfection
      • Rapid mix – achieve rapid and through dispersion of chemicals required by coagulation
      • Coagulation – modify colloidal particles, stabilizing forces are reduced for efficient aggregation during flocculation
      • Flocculation – promote the growth of the floc for removal through sedimentation and filtration
      • Sedimentation – process to separate solids from water through gravity settling
    • 71. Major Processes
      • Filtration – process to remove fine particles and floc through bed of porous granular media
      • Activated Carbon – process to absorb dissolved organic compounds for taste & odor control and color reduction
      • Softening – process to remove hardness through chemical precipitations
      • Recarbonation – process to neutralize and restore chemical balance of water after softening
      • Disinfection – process to inactivate and remove pathogens in order meet primary drinking water standards
      • Water Stability control – process to adjust pH and alkalinity by adding a acidic or alkaline compound for maintaining a non scaling and non corrosive finished water
    • 72. Intake, Screening & Aeration
      • Raw water intake : A special structure used to draw water from predetermined pool
      • Types
        • Floating, Submerged, Tower, Shore intake.
      • Screening : To remove objects carried in raw water, protect downstream equipments.
      • Types
        • Coarse, fine screens and Micro strainers
      • Aeration : Add DO, remove VOC, taste and odor causing compounds & remove CO2 and H2S by stripping
      • Types
        • Gravity, Spray, Diffused & Mechanical
    • 73. Water Conveyance, Measurement & Pumping
      • Water conveyance system : A controllable hydraulic system used to move water from one place to another
      • Flow measurement : A technique used to collect data regarding the quantity of water passing through the concerned point in the water conveyance system
      • Pumping : A technique used to impart energy into water to increase its head so that it can flow from one place to another through the water conveyance system
          • Kinetic: centrifugal and peripheral/recessed
          • Positive displacement: plunger/piston, diaphragm, rotary, screw, airlift
    • 74. Coagulation & Flocculation
      • Coagulation/Flocculation :
        • - Removal of turbidity
        • - Removal of bacteria and virus
        • - Removal of color
        • Preparation for filterable water
      • Three typically used coagulants:
        • - Ferric Sulfate: Fe2(SO4)3
        • - Ferric Chloride: FeCl3
        • Alum (aluminum sulfate): Al2(SO4)3•14H2O
      • Rapid Mix : Coagulation requires rapid dispersion of chemical throughout water and quick formation of precipitates under extremely violent agitation
      • Flocculation : Physical process used to promote the growth of the floc under slow mixing conditions.
        • Agglomeration of floc after the destabilization of particles and formation of precipitates
        • - Flocculation requires slow and gentle agitation that will not create turbulence to break up the floc particles that already formed during coagulation process.
    • 75. Sedimentation
      • A process used to separate the settleable solids from the water through gravity setting
      • Preconditions :
        • Specific gravity of the particles should be larger than that of the fluid.
      • Four types of sedimentation behaviors:
        • Type I sedimentation: discrete settling
          • individual particles settle independently, it occurs when there is a relatively low solids concentration
        • Type II sedimentation: flocculant settling
          • individual particles stick together into clumps called flocs settling, this occurs when there is a greater solids concentration and chemical or biological reactions alter particle surfaces to enhance attachment
        • Type II sedimentation: hindered or zone settling
          • particle concentration is great enough to inhibit water movement settling, water must move in spaces between particles
        • Type IV sedimentation: compression settling
          • occurs when particles settle by compressing the mass below
    • 76. Filtration
      • A physical process used to remove fine particles and floc through a bed of porous granular media.
      • • System Components:
        • - Filters
        • - Backwash system
        • Backwash waste recovery system
    • 77. Backwash
      • Backwash operation may be initiated by:
        • Exceeding preset maximum head loss
        • Experiencing turbidity breakthrough
        • Passing pre-selected run time
      • Basic design considerations include:
        • Settling velocity of the media
        • Backwash rate
        • Expansion of bed
        • Head loss during backwash
    • 78. Water Treatment
      • Taste and odor control
      • Residual Processing
      • Ion Exchange
        • A chemical process used to exchange anions or cations on a "resin" bed for cations or anions of the contaminant that needs to be removed from the water
      • Membrane process
        • A physical process using different semipermeable membranes for removal of dissolved solids as well as colloidal particles
      • Electrodyalysis
        • An electrically driven dialysis demineralization process using semipermeable to remove ions
    • 79. ENVIRONMENTAL SYSTEMS A CHEMICAL ASPECT EVSE - 5310
    • 80. Characteristics of Natural Water
      • The hydrogen bonding in the water molecule is unique and very strong
      • Density
      • Density of ice < water
      • At 3.98 ̊C  max. density
      • Water cooler than 4 ̊C will float / sink (otherwise)
      • Dissolved Oxygen (DO)
      • Refers to the health of the water body
      • High value is preferred
      • No direct method to measure oxygen demand in sewage  Complexity
      • Winkler test (titration based), electrodes (modern)
      • Approximate indirect method to measure total oxygen demand is Biochemical Oxygen Demand (BOD).
    • 81. Characteristics of Natural Water
      • Biochemical Oxygen Demand (BOD)
      • Not direct measure but gives the feel of how much oxygen is consumed by biochemical sources present in water.
      • Actually measuring  BOD 5 = DO 0 – DO 5
      • Test is an approximation – DO measured is strictly not biological
      • COD (Chemical Oxygen Demand)
      • Trying to calculate the refractory species (chemically active rather than biologically active) in the sample.
      • TOD = COD + BOD 5
    • 82. Characteristics of Natural Water
      • Total Organic Carbon (TOC)
      • Deals with organics
      • An instrumental test
      • pH
      • pH = - log [H 3 O] +
      • Practical value = 0-14
      • 0-7  Acid, 7  Neutral, 7-14  Basic
      • pH is often called the intensity factor.
      • Alkalinity
      • The capacity of water to neutralize itself
      • Greater the alkalinity the better it resists change in a pH or buffering effects
      • Buffers are a combination of weak acid and its conjugate base
      • Carbonate system is more predominant in Natural waters
      • Alkalinity test uses phenolphthalein (pink  base , colorless  acid)
      • 1 st end point – phenolphthalein – 8.3 – get the measure of Carbonate [HCO 3 ] -
      • 2 nd end point – methyl orange – 4.5 – get the measure of bicarbonate [CO 3 ] 2- and [OH] -
      • Total Alkalinity = [HCO 3 ] - + 2 [CO 3 ] 2- + [OH] -
    • 83. Characteristics of Natural Water
      • Hardness
      • Hardness is the total concentration of divalent cations (+ve charge) in natural waters.
      • Expressed as mg CaCO 3 / L
      • Predominant ions that contribute to the hardness is Ca2+, Mg2+
      • In ground water Fe2+ can be a contributor
      • All other is called Non-Carbonate Hardness
      • Total Dissolved Solids (TDS)
      • Measures the total dissolved solids
      • Measured in ppm
      • Increase in TDS means less desirable the water and is dangerous for aquatic life
      • Total Suspended Solids (TSS)
      • Suspended solids are a vehicle for transporting toxic materials
      • Turbidity
      • It is a measure of water clarity
      • Increase in TSS causes increase in Turbidity.
    • 84. Metal Ion Co-ordination Chemistry
      • Predominant dissolved metals is sodium and potassium in aquatic environment (sea)
      • Ca, Mg, K & Na can be measured in ppm or mg/L
      • All other metals are in trace concentrations in water and generally measured in ng/L or ppt, μ g/L or ppb
      • Metal ion concentration does not affect pH of water, they are of very low concentration in water.
      • A water molecule covalently bonded to a metal will be a stronger acid
      • Hydrated metal ion when behaves as an acid is called hydrolysis
      • Two species can be used to see where the Reaction is going:
        • Oxidation State
          • Increase in oxidation  more positive it becomes  stronger acidic activity
        • pH
          • Increase in pH  increase in degree of hydrolysis
      • Hydrolysis
        • Increases with increasing pH
        • Increases with increasing dilution
        • Increases with increasing oxidation state.
    • 85. Colloidal Systems
      • A colloid is a material that fall in between the homogenous and heterogeneous mixture.
      • A colloid is a homogeneous mixture of two phases.
      • One phase is called medium or bulk and the other is called the colloid
      • Colloid is pictured
        • As a particle, larger than the typical solution
        • Which cannot dissolve in a solution
        • Cannot have the precipitate or the colloid to dissolve it
      • Diameter of colloid is in the range of 0.0001 – 1 μ m
      • Colloids can be organic, inorganic & biological
      • They have very large surface area to volume ratio. It provides a site for chemical reaction and makes the reaction easier.
      • A colloidal particle is a transporter for materials from one place to another
      • Colloids are measure of TSS and Turbidity
    • 86. Colloidal Systems
      • Formation of Colloids (2 Basic models)
        • Dispersion : Process involving the reduction of larger particle to smaller size
        • Condensation : Chemical Physical process by which particles aggregate to form a size of colloidal particles
      • Types of Colloids
        • Hydrophillic : affinity for water
        • Hydrophobic : Repels water, they will stabilize in a way that they remain suspended in water (non polar molecules)
        • Association : A colloid where one end is polar and the other end is non polar.
      • Most colloids that are of concern in environment are either hydrophobic or association.
    • 87. Aquatic Microorganisms
      • Oxidation reductiom reaction is the life forming reaction of any microorganism
      • Microorganisms convert one form of chemical to another so as to recycle
      • For most digestive processes in microorganisms, they use spontaneous oxidation-reduction reaction
      • Classification of Microorganisms
        • Autotrophic (Producers) : They convert inorganic materials to organic materials
          • They depend on non-spontaneous redox process. Need a continual source of energy to keep them going
          • Sources come from two places
            • Sunlight  Photosynthetic ex. Algae
            • Chemicals  Chemosynthetic ex. Bacteria
        • Heterotrophic (Reducers or Decomposers) : Primary function is to convert organic  inorganic materials
          • They depend on spontaneous redox process
            • Aerobic : Requires direct oxygen
            • Anaerobic : Functions in the absence of oxygen
            • Facultative : can function in both presence and absence of oxygen
    • 88.
      • Almost all reactions that happen in the atmosphere are photochemical
      • Scattering
        • The path of the radiation is changed/redirected
        • Three types of scattering
          • Rayleigh <= 1(d/ λ )
            • Characteristic of this scattering is back scattering
            • Type of matter capable of doing this is the smallest of the suspended particles
          • Mie Scattering = 1
            • No back scattering
            • Large particles in suspended air scatter light
          • Optical Scattering >= 1
            • Done by Reflection, refraction and diffraction.

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