MICROSCOPY and ACTIVATED SLUDGE PROCESS CONTROL Mackenzie L. - - PowerPoint PPT Presentation

▶
microscopy and activated sludge process control
SMART_READER_LITE
LIVE PREVIEW

MICROSCOPY and ACTIVATED SLUDGE PROCESS CONTROL Mackenzie L. - - PowerPoint PPT Presentation

Oct 01, 2023 568 likes •1.19k views

MICROSCOPY and ACTIVATED SLUDGE PROCESS CONTROL Mackenzie L. Davis MWEA Process Seminar November 2015 CREDITS Activated Sludge Microscopy Notes & Thoughts The ultimate objective of activated sludge microscopy is to identify

slide-1
SLIDE 1

MICROSCOPY and ACTIVATED SLUDGE PROCESS CONTROL

Mackenzie L. Davis

MWEA Process Seminar November 2015

slide-2
SLIDE 2

CREDITS

slide-3
SLIDE 3
slide-4
SLIDE 4
slide-5
SLIDE 5
slide-6
SLIDE 6

Activated Sludge Microscopy – Notes & Thoughts

  • The ultimate objective of activated sludge

microscopy is to identify potential filamentous bacterial causes of solids separation performance problems.

  • Microscopy is only one tool.
  • The objective of this talk is to make you

aware of some of the typical microbial culprits that may be diagnosed with a microscope AND other operational data.

slide-7
SLIDE 7

Activated Sludge Microscopy – Notes & Thoughts

  • This lecture will not explain the

mechanics of microscope operation or staining techniques… Refer to WEF text

  • n microscopy.
  • This lecture WILL NOT make you an

expert in activated sludge microscopy!!

slide-8
SLIDE 8

FOCUS

BULKING & FOAMING SLUDGE

slide-9
SLIDE 9

Aeration tank in service. Faded “orange” pipes are air headers.

slide-10
SLIDE 10

Influent to activated sludge aeration tank from primary settling tank and return activated sludge (RAS) from secondary settling tank. This photo was taken in the 1970s before restrictions were placed on using phosphorus builders in detergents.

Effluent from primary settling tank

RAS “Soap” bubbles

slide-11
SLIDE 11

Oxidation ditch scum baffle and effluent structure. Foam is accumulation of bubbles that have frozen (note white ice layer near scum baffle). When the air temperature rises above 0oC the scum “melts” and dissipates.

Scum baffle

slide-12
SLIDE 12

Aeration tank in service. Start up problems with Nocardia foam.

slide-13
SLIDE 13

FACTORS AFFECTING SLUDGE BULKING

  • Design Limitations
  • Wastewater Characteristics
  • Operational Issues
slide-14
SLIDE 14

DESIGN LIMITATIONS

  • Poor Mixing
  • Clarifier Design
  • Limited Return Sludge Capacity
  • Process Loading
  • Internal Plant Overloading
  • Limited air supply
slide-15
SLIDE 15

Microscopy CANNOT Help Identify These Problems

slide-16
SLIDE 16

WASTEWATER CHARACTERISTICS

  • Flowrate Variations
  • Composition/characteristics
  • Industrial waste component/composition
  • Animal and vegetable FOG
  • Sulfur compounds
  • pH
  • Temperature
  • Nutrients
slide-17
SLIDE 17

Microscopy CAN Help Identify Composition/Characteristics Problems

slide-18
SLIDE 18

OPERATIONAL ISSUES

  • MCRT
  • Low F/M
  • Low Dissolved Oxygen
  • Nutrient Deficiency (nitrogen and

phosphorus)

slide-19
SLIDE 19

Microscopy CAN Help Identify These Issues

slide-20
SLIDE 20

Causes of Bulking Sludge and Likely Suspects

slide-21
SLIDE 21
slide-22
SLIDE 22

MCRT VS F/M

MCRT vs F/M

5 10 15 20 25 30 35 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 F/M kg BOD/kg MLSS-d MCRT, d

slide-23
SLIDE 23
slide-24
SLIDE 24

MOST UNWANTED FOR BULKING AND/OR FOAMING

slide-25
SLIDE 25
slide-26
SLIDE 26

Nocardioform Organisms

Nocardioform organisms include: Gordonia amarae, Microthix parvicella and the Following pathogens:

  • N. caviae, N brasiliensis,
  • N. asteroides, and strains of

Mycobacterium and

  • N. farcinica
slide-27
SLIDE 27

MUG SHOTS OF TOP TEN MOST UNWANTED FOR BULKING AND/OR FOAMING

slide-28
SLIDE 28

Gram Stain

  • Positive (+) => purple
  • Negative (-) => pink
slide-29
SLIDE 29
  • No. 1: Nocardia
slide-30
SLIDE 30
  • No. 2: Type 1701
slide-31
SLIDE 31

No.3: Type 021N

slide-32
SLIDE 32

No.4: Type 0041

slide-33
SLIDE 33

No.5: Thiothrix

Note: “Thio” = sulfur; sulfur granules are characteristic

slide-34
SLIDE 34

No.6: Sphaerotilus natans

slide-35
SLIDE 35

No.7: Microthrix parvicella

slide-36
SLIDE 36
  • No. 8: Type 0092
slide-37
SLIDE 37

No.9: Haliscomenobacter hydrosis

slide-38
SLIDE 38

No.10 Type 0675

slide-39
SLIDE 39

Use the “Dichotomous Key for Identification

  • f

Filamentous Organisms”

slide-40
SLIDE 40

Gram Stain

  • Positive (+) => purple
  • Negative (-) => pink
slide-41
SLIDE 41

Neisser stain

  • Positive (+) = bluish color
  • Negative (-) = brownish color
slide-42
SLIDE 42

Source: Jenkins Sulfur granules Gram positive Gram negative Neisser positive Neisser negative

slide-43
SLIDE 43
slide-44
SLIDE 44
slide-45
SLIDE 45
slide-46
SLIDE 46
slide-47
SLIDE 47
slide-48
SLIDE 48
slide-49
SLIDE 49
slide-50
SLIDE 50
slide-51
SLIDE 51
slide-52
SLIDE 52

Way Past Time to Take Corrective Action!!!

slide-53
SLIDE 53

Run for the Hills Foaming is Out

  • f Control!!!
slide-54
SLIDE 54

OUT TAKES

slide-55
SLIDE 55

MICROSCOPY METHODOLOGY

slide-56
SLIDE 56

Sampling point

  • Good mixing – end of aeration basin
  • r mixed liquor channel between aeration

basin and secondary settling clarifier Take mixed liquor samples from below surface to exclude foam

slide-57
SLIDE 57

Sampling point

  • Sample foam from one of following points
  • (1) Surface of effluent end of aeration

basin

  • (2) Surface of mixed liquor channel
  • (3) Surface of secondary clarifier
slide-58
SLIDE 58

Sampling Frequency

  • (1) Routine on site examination
  • About once every MCRT
  • (2) Routine off-site laboratory
  • Weekly to monthly
  • (3) Daily for critical periods
  • (a) When bulking occurs
  • (b) During RAS chlorination

for bulking control

slide-59
SLIDE 59

Sample Transport and Storage

  • (1) Examine as soon as possible after collection

but not more than several hours

  • (2) For more lengthy periods store at 40C
  • Low F/M; High MCRT – within 7-10 days
  • High F/M; Low MCRT – within 3 to 4 days
  • (3) Transport in small plastic containers (not

glass)

  • (4) Do not fill containers more than half full
slide-60
SLIDE 60

Microscope

  • Use a research grade, phase contrast

microscope with 10x and 100x (oil immersion) phase contrast objectives that yield magnifications of approximately 100x and 1000x respectively. Use phase contrast because biological materials have very low contrast when viewed with direct illumination.

  • COST = about $5,000