Bioscience, Inc.

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Bioscience, Inc.

• Allentown, PA
• www.bioscienceinc.com

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The Biological Process of Wastewater Treatment

• Jay Hill
• Product Manager

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Typical Wastewater Treatment Steps

• Coarse Physical Treatment
• Settling of Suspended Solids/Floatables
• Biological Treatment of Dissolved/ Fine Solids
• Recovery of Biomass
• Removal of Inorganics
• Disinfection
• Excess Biomass Removal

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Primary Treatment

• Bar Screen
• Clarifier
• Primary sludge
• Sand/grit
• Coarse organic matter
• Floatables
• FOG
• DAF or API Separator
• FOG, petroleum HC, light solids

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Activated Sludge Systems
O2
CO2
Untreated Discharge
Clean Water
Aeration Tank
Clarifier
Recycled Sludge
Biomass (Secondary Sludge)
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Secondary Clarification

• Clarifier
• Secondary sludge
• Fine organic matter
• Floatables
• FOG

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Solids Processing

• Sludge Thickening
• Aerobic or Anaerobic Digestion
• Centrifuge
• Belt Press
• Incineration, Land Application, Fertilizer,
  Landfill

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Aerobic Microbial Respiration

C,H O2 CO2 H2O
protein
bacteria, N, P, pH, temperature
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Composition of Wastewater

• Inorganics
• Ammonia
• Nitrate
• Phosphate
• Carbonate
• Minerals
• Calcium
• Magnesium
• Iron
• Etc.

• Organics
• Biodegradable (BOD)
• Carbohydrates
• Proteins (TKN)
• FOG
• Non-Biodegradable (COD-BOD)
• Large particles
• Complex polymers (plastics, lignin)
• Surfactants (some)
• Pesticides (some)
• Pharmaceuticals (some)

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Requirements for Growth of Microbes

• Temperature
• pH
• Water activity
• Energy source
• Nutrients
• Carbon
• Nitrogen
• Phosphorus
• Minerals
• Vitamins/growth factors

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Temperature

• Thermophiles
• 40C to gt100C
• Mesophiles
• 10C to 45C
• Psychrophiles
• lt5C to 35C

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pH

• Acidophiles
• pH 0-6
• Alkaliphiles
• pH 8-13
• Most bacteria prefer pH 6-8
• Most fungi prefer pH 4-7

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Water Activity

• Salt content of water
• Fresh water lt1 NaCl (most bacteria)
• Brackish water 1-3 NaCl (limits some species)
• Seawater 3.5 NaCl (salt tolerant only)
• Saline water up to 30 (saturated NaCl)- (only
  few species)
• Soils (moisture content and salts)
• 50-100 FMC (most bacteria)
• Fungi tolerate lower moisture content

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Energy Sources

• Oxygen (aerobes) C6H12O6 6 O2?6 CO26 H2O
• Autotrophs
• NH4 2 O2? NO3- H2O 2 H (Nitrifiers)
• H2S 2 O2 ?SO4 - - 2 H (sulfur oxidizers)
• H2S 0.5 O2 ?S0 H2O (sulfur oxidizers)
• Nitrate (facultative) C6H12O6 6 H2O ?6 CO2 12
  H2 / 5 H2 2 NO3 - 2 H ? N2 6 H2O
  (denitrifiers)
• Sulfate (anaerobes) C2H4O2?CO2 / SO4 --? H2S
  (sulfate reducers)
• Carbon dioxide (anaerobes) CO2 4 H2 ?CH4 2 H2O
  (methanogens)
• Fermentation C6H12O6?2 CO22 C2H5OH

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Nutrients Required for Growth

• Carbon
• Usually from food source or CO2
• Nitrogen
• Usually from ammonia, nitrate or simple organics
  (amino acids)
• Phosphorus
• Inorganic phosphate
• Sulfur
• Inorganic sulfate or simple organics
• Minerals (Ca, Mg, K, Na, Fe)
• Trace elements (Ni, Co, Cu, Mo, Zn)
• Growth factors/vitamins

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Operation Limits

• pH 6-9
• lt4 Most bacteria dead or inactive
• lt6 Bacteria activity drops, fungi may create
  settling problem
• lt6.5 Nitrification very poor
• 7.5 optimum for hydrocarbons, fog,
  nitrification, sulfide
• gt9 Bacteria activity drops

• Nutrients
• BODNP 10051
• Effluent ammonium-N lt2 mg/L may limit BOD removal
  or slow response to slug loading
• Effluent ammonium-N lt0.5 mg/L probably deficient
  unless nitrifying (nitrate provides N)
• Effluent ortho-phosphate lt1 mg/L may limit BOD
  removal or slow response to slug loading
• Effluent ortho-phosphate lt0.2 mg/L probably
  deficient

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Operation Limits

• Temperature
• lt5C Few bacteria are active
• lt15C Nitrification and most bacteria growth very
  slow
• 20-35C Optimum for most bacteria
• 39-45C Bacteria activity drops, death rate
  increases
• gt45C Only adapted or thermophilic processes occur

• Biomass
• MLSS normally 1500-6000 mg/L
• lt1500 poor settling, dispersed
• gt6000 oxygen limited? may overflow clarifier
  weir
• MLSS/MLVSS 80-90
• lt80 low viable percentage, possible accumulation
  of inert
• lt70 may occur in aerobically digested sludge
• gt90 light (poor settling) floc

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Operation Limits

• Sludge Age/MCRT
• lt3 days Poor settling/COD removal/high sludge
  production
• lt8 days May have poor nitrification
• gt20 days May have filament problems or pin floc
  good for exotic chemical degradation and sludge
  digestion

• SOUR
• Complete mix system 3-15 mg O2/g MLSS per hour
• lt3 Inhibition or severe underload
• gt15 Slug load/ possible overloading
• Staged aeration 1st Stage
• 30-100 mg O2/g MLSS per hour
• lt20 Inhibition
• lt30 Insoluble waste
• gt100 Overloading

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Operation Limits

• Dissolved Oxygen
• 2-7 mg/L normal range
• lt0.5 Anaerobic
• lt1 General BOD removal slows
• lt2 Nitrification slows
• gt7 Slow growth (inhibition) or underloaded
• gt9 Bacteria dead or inactive

• Sludge Blanket
• Normal range 3-7 ft below surface
• lt3 feet(1 meter) poor settling or compaction
  biomass may washout with flow increase
• gt7 feet (2 meters) Rapid settling may leave
  dispersed solids in effluent

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Typical Upsets
Heavy Organic Load
Increased Growth/Respiration
Reduced Dissolved Oxygen
More Sludge to Clarifier
Reduced Growth/Respiration
Inadequate Removal
Deflocculation of the Biomass
Poor Settling
Elevated BOD/COD
Worse Effluent
High Effluent Suspended Solids
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Common Wastewater Problems

• Poor Settling
• Effluent Violation (TSS or BOD)
• Filamentous Forms
• Poor Nitrification
• Toxicity
• Odors

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Aerobic Microbial Respiration

C,H O2 CO2 H2O
protein
bacteria, N, P, pH, temperature
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Chemical Characterization of VISC 25
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Wastewater Treatment Plant Performance Testing  

• Process control tests or performance evaluation
  tests to determine overall treatment process
  efficiency, identify or investigate problems, or
  evaluate specific ability to treat target
  compounds. Process control tests generally must
  be quick turnaround tests usually performed
  on-site to allow process adjustment in response
  to problems. However, some longer time-frame
  tests may be set up to predict or determine the
  effect of process changes or identify trends in
  process efficiency.
• Some of the investigations performed by
  Bioscience have been designed to
• evaluate foam or settling problems
• measure nitrification rates or nitrification
  potential
• measure FOG degradation rates or potential
• measure permissible loading rates for potentially
  toxic waste streams or septage
• measure effectiveness of bioaugmentation
• measure biomass kinetic constants for process
  design.

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Wastewater Treatment Plant Performance Testing  
Available methods include Standard Methods 5210D
Biochemical Oxygen Demand Respirometric Method
(Respirometric Oxygen Uptake) Standard Methods
2710B Oxygen-Consumption Rate (Specific Oxygen
Uptake Rate Dissolved Oxygen Probe Method) OECD
209 Activated Sludge, Respiration Inhibition
Test ASTM D5120 Standard test Method for
Inhibition of Respiration in the Activated
Sludge Process Short-Term BOD Test (EZ-BOD
instrument test for influent or effluent BOD-5
estimation) Suspended Solids (Photometric
Method) CONTRAL Biodegradation Kinetics Microscopi
c Evaluation of Biomass (Higher Forms and
Filaments)
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Wastewater Treatment Problems (AS)
Problem Cause Cure
FOG in collection Various DNT-RF/GEL
Odor/H2S Anaerobic condition DNT-RF/ANL
FOG in aeration basin Slow digestion DNT-RF/SXM/NPN/TM
High temperature/low activity Hot process water HT
No or partial nitrification Toxicity/low temp/low SRT/nutrients XNC/XNL/TM
Low COD or specific compound removal Low temp /various/industry specific HX, XR, XP, etc.
Excessive filaments various XF, SXM, nutrients
Excessive sludge FOG/cellulose/etc accumulation in sludge SR
Poor sludge digestion Nutrient imbalance/FOG AD, SXM, TM
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Wastewater Treatment Problems (Lagoon)
Problem Cause Cure
Odor/H2S Odor/NH3 Anaerobic condition High NH3 /High pH ANL/TN and/or aeration ECL
FOG in aeration basin Slow digestion DNT-RF/SXM/NPN/TM
High temperature/low activity Hot process water HT
No or partial nitrification Toxicity/low temp/low SRT/nutrients XNC/XNL/TM
Low COD or specific compound removal Low temp /various/industry specific LF, HX, XR, XP, etc.
Excessive sludge FOG/cellulose/etc accumulation in sludge SR
Animal waste consistency High solids DL
Algae High nutrients (N,P) AL/ALN
Poor denitrification Low facultative population DEN
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Bioaugmentation
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How Does Bioaugmentation Work?

• Numbers By adding cultures regularly the
  minor cultures (but important cultures) gain a
  survival advantage (against the dominant
  cultures) .

• Natural Genetic Interchange Recent work
  indicates the possibility of transfer to the
  biomass of desirable and needed characteristics
  (but not permanently), particularly capabilities
  controlled by the plasmids in the cells and
  demanded by the conditions in the system.

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Activated Sludge- Culture Selector
The biomass is comprised of thousands of cultures
of bacteria, fungi, protozoans, etc. The system
selects cultures with both major/dominant
populations and minor counts. Both populations
are important in obtaining good effluent
quality. The combination of cultures in the
biomass continuously changes and adapts to
changes in ambient conditions.
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Major Versus Minor Cultures

• Major Cultures
• Grow rapidly
• settle well
• control the general nature of the biomass

• Minor Cultures
• Produce important results
• Are more difficult to maintain in the
  biomass

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The Transfer of Plasmids
a
b
d
c
Scientific American, January 1998, p. 68
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Bioaugmentation Benefits

• Benefits for Wastewater Treatment
• Reduce Effluent Peaks (NPDES outages)
• Reduce Effects of Toxic Compounds
• Improve Settling Thru Filament Control
• Enhance Process Stability
• Reduce Sludge Production
• Minimize Downtime/Reduce Labor

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Filamentous Populations
Individual microbes do the work
Microbes flocculate and form particles that settle
But the filamentous forms inhibit settling
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Nitrification
2NH4 3O2 2NO2-
4H 2H2O
2NO2- O2 2NO3-
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NH3 Treatment System
Removal of insolubles
Removal of BOD
Clarifier
Recycle of Sludge
Removal of NOD
Discharge of Sludge
Clarifier
Recycle of Sludge
Discharge of Sludge