September, 2016
- The term pathogenic means
a) Aerobic Bacteria
b) Anaerobic Bacteria
c) Fecal Matter
d) Coliform Bacteria
e) Capable of Causing Disease
- The minimum separation between sewer lines and potable water lines is –
a) 1 foot
b) 5 feet
c) 10 feet
d) 24 feet
e) 50 feet
- A licensed wastewater operator is a professional who
a) Consistently does the best job possible
b) Practices personal safety
c) Strives to improve job knowledge
d) Strives to keep the plant and collection system in the best appearance and working order
e) All the above
- An important step in testing a sample for Total Suspended Solids (TSS) is
a) Settling the sample
b) Filtering the sample
c) Incubating the sample
d) Burning the sample
e) Evaporating the sample
- The Biochemical Oxygen Demand (BOD) of a sample is based on –
a) pH readings
b) Measuring Total Suspended Solids (TSS) of a sample
c) Measuring the Dissolved Oxygen (DO) used
d) Measuring the anaerobic decomposition
e) Measuring total detention time
- The results of a Biochemical Oxygen Demand (BOD) sample taken at a treatment a) plant tells the operator –
a) How the plant is currently operating
b) How the plant was operating 5 days ago
c) How the plant was operating 10 days ago
d) Is of no benefit to the operator
e) How the plant will be performing at TCEQ inspection time
- Which of the following are dangerous gases that are likely to be present in lift stations and or manholes?
a) Natural gas and Gasoline fumes
b) Hydrogen Sulfide and Carbon Dioxide
c) Hydrogen, Sulfur, and Argon
d) Oxygen, Nitrogen and Helium
e) Both a & b
- A preferred hydraulic method of cleaning sewer lines is –
a) Cable & Auger
b) Continuous Roding Machine
c) Hydro Jet Cleaner
d) Bucket & Belt Press
e) Both a & d
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The common misconception is that if you have foam on the surface of your aeration basin, you must have Nocardia. Not all wastewater foam is due to Nocardia! Foam can be caused by many other species, such as Microthrix, or operational problems such as having too many solids, low D.O., zoogleal bulking and others. Are you having problems with grease? Low nutrients and high loading due to industry can also cause foaming, as well as septicity.
It is not enough to look at the foam and assume it is caused by Nocardia or Microthrix. To properly identify the foam one must looked under the microscope at the actual filaments and perform a Gram or Neisser stain. The plant below, for example had foaming because the plant had too many solids in one of three basins and was also holding solids too long in the clarifier. The biomass had N. Limicola as the dominant filament. The plant needed to make a number of process changes as opposed to just "adding bacterial product" as a quick fix.
The cause of the foam problem was determined using process monitoring and control. Investigations determined that all three basins, while the same size and shape, in realty were not all alike. Flows to each basin had varied over the years as old pipes became clogged. MLSS was not routinely measured in each basin. Process monitoring revealed that the basin with the foaming problem had too many solids, which led to the foaming problem. Changes to step feed were also recommended since the final basin was also low on F/M. The plant did not routinely check D.O. levels in each basin either. Small changes in D.O. also helped create conditions that literally caused the filamentous bacteria to thrive when they finally reached the last basin in the process.
Always do a walk-through of your plant, look for trouble areas. Are you creating dead spots in the primary that can cause problems? In the secondary, in the clarifier, in the sludge holding tank, digesters or in the dewatering and returned supernatant?
Not all foam is bad, but the presence of foam usually indicates a condition that is going on in your basin. Learn what the colors mean. . . .
A typical troubleshooting foaming chart is shown below that can be helpful. Be careful though, and use your microscope or you may make the wrong interpretation as to what is causing the foam and how to fix it.
Keeping track in a daily log sheet, using photographs, correlating data to MLSS and settleometer data as well as using the microscope are simple suggestions and are all ways to help you understand what is going on in your wastewater treatment system.
Remember - it is in reality a "bug factory” - you are growing bacteria to make clean water! Start thinking like a bug. . .
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Nocardia Foam |
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Foaming due to septicity at a municipality and resulting in heavy filaments. |
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M parvicella foam, forms stable dark brown greasy foam that can get thick enough to have a crust. |
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Zoolgeal bulking, generally due to high BOD loading |
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Normal aeration, healthy bugs! |
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White crisp foam, generally due to young sludge or high recent BOD loading. |
White, stiff, billowing or sudsy foam covering a large part
of or the entire aeration basin.
Start-up
or high BOD shock load condition resulting in high F/M and low MCRT.
Increase
RAS or decrease WAS, do not waste until MLSS level comes up to proper F/M
range. Maintain adequate DO levels (1 to 3 mg/l).
Reduce
wasting and adjust RAS until normal conditions are reached.
Excessive
wasting or hydraulic washout.
Segregate
stormwater lines from process water collection system.
Divert
excessive flows to collection basin if possible for later treatment.
Add
hydraulic equalization basin.
Toxic
wastes or temperature shock.
Re-establish
activated sludge organisms. Waste sludge
from plant if possible. Re-seed if
possible (bioaugmentation). Re-establish
normal temperature if possible or adjust MCRT if situation is to continue.
RAS
flow too low or off
Re-establish
adequate RAS rate.
Excessive dairy fats, detergents or other
foaming materials or surfactants.
Pre-treat
with anti-foam or DAF. Improve primary
oils and grease removal. Consider bio-augmentation to more aggressively degrade
waste substrate.
Shiny, thin, dark tan foam on much of aeration basin
surface.
Aeration
basin approaching under loaded (low F/M) condition due to insufficient sludge
wasting (too many solids in the
system).
Increase
WAS rate (not more than 10% per day) until process approaches normal control
parameters and only a modest amount of
light tan foam remains on aeration basin surface. Check MLVSS, F/M and MCRT to optimize.
Thick, greasy dark-
tan foam covering most of the aeration basin surface.
Aeration
basin is critically under loaded (excessive solids due to insufficient wasting).
Increase
WAS rate (not more than 10% per day) until the excess solids are removed from
the system and normal balance is restored.
Check MLVSS, MCRT and F/M ratio to optimize process parameters.
Thick, greasy dark tan foam covering most of the aeration
basin surface, and carries over to the clarifier (and sometimes over the basin
sidewalls).
Filamentous
organisms (Nocardia, M. parvicella)
Increase
WAS rate (not more than 10% per day) to reduce MCRT. Normal filamentous control with chlorine or
peroxide must include treatment (in
water spray) and removal of surface scum (foam) in addition to RASS/MLSS as
these organisms tend to concentrate in the foam. Check MLVSS and F/M ratio to optimize process
parameters.
Dark brown, almost
black sudsy foam with detectable septic or sour odor. Mixed liquor is also very dark brown to black
in color.
Anaerobic
conditions within the aeration basin.
Check
DO levels in basin, and increase aeration / mixing. Reduce organic loading if possible.
Industrial
waste containing dyes or inks.
Investigate
pre-treatment strategies.
Modest amount of fresh, light tan foam.
Not a
problem!
Usually
a sign of a well operated process.
September
TBD - MRWA - Lagoon Day
September 1 - MWUA - 2016 Drinking Water Protection Seminar - "It's
Not Just Lead & Copper, It's Customer Engagement", Governor Hill
Mansion, Augusta
September
10 - MeWEA
- Portland Greenfest, Portland
September
12, 14, 19, 21, & 26 - MRWA - VSWS and
Class 1 Water Operator Certification Exam Prep Course, Newport / Richmond, ME-WOB
25.0 TCHs
September
12 - NEWEA - Collection Systems & Exhibit,
Holiday Inn, Boxborough, MA, NEWEA-362-WW-6
September
13, 15, 20, 22, & 27 - MRWA - VSWS and
Class 1 Water Operator Certification Exam Prep Course, Farmington / Presque
Isle, ME-WOB 25.0 TCHs
September
14 - MeWEA
– MeWEA Golf Tournament, Sugarloaf Mountain
September
14, 15, & 16 - MeWEA – MeWEA Fall Convention, Sugarloaf Mountain
September
24 through 28 - MeWEA – WEFTEC
October 5
- MRWA - Maine Utility Rodeos,Rumford, ME-WOB 6.0 TCHs
/ ME-DEP 3.0 TCHs for Safety & 3.0 TCHs for Wastewater
October 6
- MRWA - Maine Utility Rodeos, Limestone, ME-WOB 6.0
TCHs / ME-DEP 3.0 TCHs for Safety & 3.0 TCHs for Wastewater
- e. Capable of Causing Disease
- c. 10 feet
- e. All the above
- b. Filtering the sample
- c. Measuring the Dissolved Oxygen (DO) used
- b. How the plant was operating 5 days ago
- b. Hydrogen Sulfide and Carbon Dioxide
- c. Hydro Jet Cleaner
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