The Adventures of Sludge Bugs

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The Adventures of Sludge Bugs

• Betsy Betros
• Johnson County Environmental Department
• Kansas Water Environment Association
• Annual Meeting
• April 3, 2007

betsy.betros_at_jocogov.org
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• Sludge bugs is a fun way to refer to the
  microorganisms which inhabit wastewater treatment
  systems.
• Sludge bugs include tiny single celled organisms
  such as bacteria too small to be seen
  individually, to big aquatic earthworms, visible
  to the naked eye.

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• Microbe identification primarily for activated
  sludge plants.
• WWTPs are designed
• to provide Utopia for sludge bugs.

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Keeping the Bugs Happy Utopia
Happy Bugs
Unhappy Bugs

• All they ask of us is to provide them plenty of
  oxygen and food and some extra nutrition if the
  wastewater is a little shy on some.
• And in turn they eat and eat and eat and begat
  and begat and begat lots more sludge bugs!

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Nice to have some micro critters that will eat
our sh..!Keeping the Bugs Happy isnt always
easy! SoGet to know your neighborsthe sludge
bugs!
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Micro-managing.the sludge!(they wont mind!)

• Observe on a routine basis. Need to understand
  growth patterns.
• Once a week is good.
• If problemsmay need to do more often.

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Microbes, as with all living things, will live
where they can live.

• Every species has tolerance limits.
• Physical factors availability of nutrients,
  temperature, dissolved oxygen level, toxicity of
  substances, pH, etc.
• Biological factors availability of food source,
  competition for food, etc.

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Its all about ecology interactions of organisms
with each other and their environment to provide
a sustainable biological community.
From Microbiology for Sanitary Engineers, Ross
McKinney
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Bacteria are Key to the Efficiency of Wastewater
Treatment

• Bacteria are not easily identifiable just looking
  at through a microscope. Use other microbes as
  indicators.
• Yet, it is the bacteria which are chowing down
  on all that tasty organic matter and
  stabilizing it by turning it into more
  bacteriawhich can form floc and be removed from
  the system through settling.
• McKinney and Horwood discovered in the early
  1950s that many bacteria are capable of floc
  formation.
• Bacteria do not actually chow down on
  foodthey do not have mouths. A molecule of food
  lines up with a reactive site on the body, and
  with enzymes, a chunk of the molecule is taken
  into the body at a time, until the remaining
  portion of the molecule is no longer digestible.

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When lots of soluble food and limited microbial
life

• Bacteria, phytoflagellates dominate-take in food
  thru cell walls.
• Bacteria reproduce fast and quickly out-compete
  the flagellates for the food.
• The phytoflagellates die off.

• Must have bacterial growth (prey) before the
  protozoa (predators startup)

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Microscopes

• Compound Microscope vs. Stereoscope.
• Compound high magnification, light goes through
  sample and image appears flat.
• Stereoscope low magnification, usually for
  viewing opaque objects, using reflected light,
  image is 3 dimensional because there are two
  complete sets of optics for each eye piece.

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Stereo Viewing-3D

• Not needed for process control, but get a whole
  different view of microbes in 3D.

Can use transmitted light or reflected light.
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Important Features of Microscope

• Use a microscope with two eyepieces.
• Mechanical stage.
• 3 objectives 5X 10 X 40X or similar range.
• Oil immersion difficult to use with wet mounts.

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Phase contrast versus flat field

• Phase contrast is not
• necessary for much
• routine work.
• Butit can be very nice, since can see body parts
  much easier.

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Dark Field Microscopy
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Using the Microscope

• Collect a sample of MLSS.
• Mix Well.
• Put 1 to 2 drops on the microscope slide.

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Get Used to Looking thru Scope

• Dont worry about
• names at first.
• Draw simple sketches,
• make up a name.
• Look for the common ones first.

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Develop a way to record your observations.

• Actual counts have limited use.
• Maybe use a cross between quantitative and
  qualitative.
• e.g. rare, occasional, common.
• Variety of types is more important.

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Look at Whole Slide First-under low power

• Is anything moving?
• Are there any filaments?
• Space between floc clear?
• What are larger animals?
• What is the appearance of the sludge granular,
  flaky, normal, dark, light?

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Is it Floc?

• Floc is made up of living and dead bacteria which
  gives it an organic look.
• Dirt is made up of minerals which gives it an
  inorganic look.

Floc
Dirt
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Is it Floc?

• Dirt minerals

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Appearance of Floc

• Look at under low power.
• Is floc well-formed?
• Is space between floc clear?
• Is it normal for your plant?

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Appearance of Floc

• Look at under high magnification.
• Filament statuslots, not many.
• Well formed floc?

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Appearance of Floc

• Older sludges may become more dirt-like.
• Darker, denser.

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Appearance of Floc

• Type of aeration affects floc size.
• Inadequate shearing, develops thicker floc which
  can promote filamentous bacterial growth which
  starts growing in the anaerobic insides of the
  thicker floc.

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Appearance of Floc

• Heavy polymer use can yield odd looking sludge
  that still settles okay.

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Next Look at Filaments

• Not necessary as a backbone.
• Most sludge will have some type of filamentous
  growth.
• Usually bacterial.

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Filaments woven through floccules

• Most sludges will tend to have these types, but
  not often a problem.
• Poor shearing of sludge by aeration system, can
  lead to extensive growth.
• Slower settling sludge.

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Filaments-Extended from Floc

• Most common is Sphaerotilus, a filamentous
  bacteria.
• Filaments branching.
• Low oxygen.
• Can grow in high oxygen, if thick floc.

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Filaments-Sphaerotilus sewage fungus

• Grossly polluted water ways can have extensive
  growths of Sphaerotilus.
• It is bacteria, not fungus.
• Great indicator organism.

Dark field illumination, stereoscope. From a
creek contaminated with soft drink waste.
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Filaments-Extended from Floc

• Pin Point Floc-undesirable, poor settling.

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Filaments-Extended from Floc

• Sludge BBs
• Extended aerationwinter, reduced aeration,
  resulted in slow roll.
• Created BBs with filaments. Anaerobic in center
  of floc.
• Sunk like a rock.

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Filaments-Free from Floc

• Sulphur bacteria.
• Can see sulphur granules in the filaments.
• Serious oxygen problems!

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Filaments-Free from Floc

• Nocardia, a fungus.
• Free from floc.
• Short branches.
• Thrives in foam from over-aged sludge which is
  the brown, greasy type.
• Greasiness is the polysaccharide buildup.

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Filaments-Free from Floc

• Dried sludge on microscope slide.
• Sometimes
• easier to assess
• filaments. Can
• backtrack when
• it starting
• developing.

Dried Nocardia
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Other Filaments

• Fungus growth.
• Low pH.
• Over digested sludge-
• nitrous acid can form.
• Low N and P.

Fungal finger-like growth from a grease ball.
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Other Filamentous-looking microbes

• Cocci chain bacteria.
• Lots of soluble food.
• Low D.O.
• Serious operational problems!

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Next-Look at the Sludge Bugsbut firstis it a
Sludge Bug?!

• If it is alive, it probably will move!
• Air bubbles, cloth fibers, dirt, etc. often
  deceive the beginner.

• Air Bubble

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Is it a Sludge Bug?

• Human hair-large strands
• Lint-small strands.

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Is it a Sludge Bug?

• Polyester Fibers

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Is it a Sludge Bug?

• Toilet paper

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Is it a Sludge Bug?

• Sometimes, just wont know what it is!

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Major Groups of Sludge Bugs Protozoa, Worms,
Rotifers, Water Bears, Gastrotrichs
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Protozoa and Other Microbes

• Easily viewed under a microscope.
• Excellent indicator organisms.
• With practice are fairly easily identified.
• Most feed on bacteria.

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Look at Bigger Ones to Start

• Why?
• Well..theyre big and easier to see!

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Two Common Worms

• Round Worms
• Aquatic Earthworms

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Round Worms

• In WWTP are free-living.
• Move by whipping body back and forth.
• Common in activated sludge, need good D.O.
• Eat chunks.
• Not usually a problem.
• Not segmented.

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Aquatic Earthworms

• Like garden worms-stiff hairs.
• Segmented.
• Indicator of older sludges.
• Eat chunks of floc.
• Can be seen in supernate with the naked eye.

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Aquatic Earthworms

• Aelosoma-sometimes common.
• Orange globules id it.
• Aulophorus-forked tail.
• The older the sludge, the more aquatic
  earthworms.
• Not usually considered a problem.

Aelosoma
Aulophorus
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Water Bears

• Tartigrades
• Multi-celled
• Fun to watch
• High survival skills!
• Water bears can survive years in a desiccated
  state and can form a cyst state.

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Water Bears

• Females expel eggs into their cuticle that they
  shed.
• Most species are semi-aquatic.
• Generally, found more often in older sludges.

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Gastrotrichs

• Ciliated, multi-celled animal.
• Appear to have a neck.
• Smooth, gliding type movement, usually associated
  with a substrate.
• Eat bacteria, protozoa, algae.
• Only females known.

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Seed Shrimps

• Ostracoda
• Occasionally seen, not important in process
  control evaluation.

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Rotifers

• Multi-celled animal.
• Important process control indicators.
• Many species-aquatic and semi-aquatic, from the
  Arctic to Antarctic!
• Few males known.
• Two major groups.

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Rotifers-two groups
Philodina

• Bdelliod inchworm-like
• Ploimate usually with a shell

Platyias
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Rotifers

• Feed on chunks of floc.
• Wheel animals
• Cilia on head, pulls food inside.
• Mastax, food grinder unique to rotifers.

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Rotifers

• Well run plant.
• Plenty of oxygen.
• Mere presence doesnt mean alls well.
• Number and condition
• Ext. Aer. Plants tend to have highest diversity.
• Which specific type in plant, might not be
  significant.

Adineta
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Rotifers can feed on chunks of flocrather than
depending on free-swimming bacteria.
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Rotifers
Desiccated Philodina

• The inchworm-type is capable of forming a
  desiccated state to survive bad times,
  particularly low oxygen.
• Important indicator.

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Rotifers

• Monostyla
• One foot

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Rotifer

• Cephalodella2 feet

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Common Protozoa

• Flagellates
• Amoeba
• Free Swimmer
• Crawlers
• Stalked Ciliates

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Protozoa-Flagellates (wigglies!)

• Phytomastigophora take in food through their cell
  membrane. Only common when lots of food and few
  bacteria.
• Zoomastigophora are animal-like in that they
  ingest their food, bacteria.
• Which type you have? Really doesnt matter to
  identify.

• Tiny, wiggly.
• Very common at startup and recovery.
• Will always have some.
• Lots indicate lots of soluble foodthey can
  compete with bacteria at that time.

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Protozoa-Flagellates

• Peranema-largest, not unusual to have in sludge.

• Single cell animals.
• Use a flagellum to move and to bring food into
  mouth.

Flagellum
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Protozoa-Flagellates

• Dinobryon, large, colonial flagellate.
• Can swim freely.
• Seen occasionally.

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Other little wigglies

• spirillium bacteria
• Quite visible and mobile.
• Lots indicate poor conditions-low oxygen.

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Protozoa-Amoeba

• Will always have some.
• Lots more at startup and recovery.

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Protozoa-Amoeba

• Move by pushing out cell wall.
• Feed by engulfing food-bacteria, algae with cell
  wall.
• Tiny amoeba-Vahlkamfia-if lots, poor conditions.

Mayorella
Vahlkamfia
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Protozoa-Amoeba

• Shelled amoeba
• testate.
• They actually make shells by cementing together
  tiny sand grains!
• Arcella and Euglypha most common.

Arcella
Euglypha
Arcella
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Scanning electron photograph of Euglypha
Made of silica.
From The Biology of Protozoa by Michael Sleigh
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Ciliates-Free Swimmer

• Fine hair-like cilia for swimming and food
  gathering.
• Can swim freely
• thru water.
• Primarily feed on free-swimming bacteria. Some
  are predaceous.
• High energy needs.

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Ciliates-FreeSwimmers

• Paramecium
• Rare in activated sludge.
• Common in trickling filters.
• Negatively geotactic! (they wont sink!)

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Ciliates-Free Swimmers

• Cyclidium
• Feed on bacteria.
• Tends to be more common in poorer conditions.

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Ciliates-Free Swimmers

• Coleps
• Barrel shaped.
• Move, in a spinning rolling motion, like a
  football.
• Predaceous on other protozoa.
• Sensitive to NH4 and free ammonia. (Bick)

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Ciliates-Free Swimmers

• Bacteria eater..note cytostome. Also eat diatoms
  and cyanobacteria.
• Not uncommon even in well run plants.
• scrubbrush

• Chilodenella

Mouth, (Cytostome)
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Ciliates-Free Swimmers

• Chilodenella
• Conjugation-type
• of reproduction

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Ciliates-Free Swimmers

• Trachelophyllum
• billy club, eat bacteria.
• Not uncommon even in well run plants.
• Very flexible bodies.

Trachelophyllum-mouth on very end
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Ciliates-Free Swimmers

• Litonotus, predaceous

Litonotus-mouth on side
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Ciliates-Free Swimmers

• Amphileptus
• Note food vacuoles.
• Carnivorous on stalked ciliates. (Bick)

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Ciliates-Free Swimmers

• Colpidium, kidney shaped.
• Feed on bacteria and small flagellates. (Bick)
• If common, likely indicating poorer
  conditionsespecially low oxygen.

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Ciliates-Crawlers

• Have thick cilia called cirri.
• Crawl over substances.
• Not so good at swimming freely.
• Indicators of stable sludge, healthy conditions.

Crawlers and free-swimmers were lumped in as one
group at the time of this chartlater separated.
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Ciliates-Crawlers

• Euplotes
• This is one similar to Aspidisca, but more
  ellipsoid in shape.
• Can graze on bacteria associated with the floc
  rather than free-swimming bacteria.
• Lower energy needs than free-swimmer ciliates.

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Ciliates-Crawlers

• Euplotes
• Predaceous on flagellates, algae, ciliates,
  bacterial colonies. (Bick)

Suctorian having a tasty Euplotes for lunch.
Side view.
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Ciliates-Crawlers

• Aspidica feed on bacteria.
• Often the most common along with the stalked
  ciliate, Vorticella, in a healthy activated
  sludge.
• ruffles potato chip

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Ciliates-Crawlers

• Aspidisca
• Reproduction via cell division.

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Ciliates-Crawlers

• Oxytrichs feed on algae, flagellates, and
  ciliates. (Bick)

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Ciliates-Stalked Ciliates

• Attached to a substrate by a stalk.
• Cilia on head for bringing food into mouth. All
  are bacteria feeders.
• Usually indicative of healthy conditions in
  activated sludge.
• Types and condition do vary with activated sludge
  conditions.

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Ciliates-Stalked Ciliates

• Two major groupscolonial and single.
• Three main groups of colonial stalked ciliates in
  activated sludge Epistylis, Opercularia, and
  Carchesium.
• One main group of single stalked
  ciliatesVorticella.

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Ciliates-Stalked Ciliates
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Ciliates-Stalked Ciliates

• Epistylis
• Large colonies.
• Stalks are non-contractile.
• Heads are like Vorticella.

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Ciliates-Stalked Ciliates

• Opercularia
• Colonial stalked ciliate.
• More common at start up and recovery.

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Ciliates-Stalked Ciliates

• Opercularia
• Note cap on head operculate.

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Ciliates-StalkedCiliates

• Carchesium
• Contractile stalk, note myoneme within stalk
  which provides this action.
• Heads are like Epistylis and Vorticella.
• Good sludge conditions.

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Ciliates-Stalked Ciliates

• Vorticella-stalk can contract due to myoneme.
• Variety of species in activated sludge.
• Note large nucleus.
• Note dots on stalk-this particular species is
• V. picta.

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Vorticella of poor conditions

• Tiny Vorticella.
• These arent baby vorticellas!
• Poor conditions.

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Stalked Ciliates of poor conditions

• Most stalked ciliates need good oxygen.
• Will try to escape if conditions get bad.
• Form a girdle of cilia.

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Stalked Ciliates of poor conditions

• Body detaches from stalk with a free-swimming
  telotroch stage to help it get out of Dodge!
• Not indicative so much of toxic conditions.
  Usually oxygen-- telotroch needs to time to form.

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Stalked Ciliates of poor conditions

• Vorticella reproducing by cell division
• If lotstheyre trying to get out of Dodge, too!

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Stalked Ciliates of poor conditions

• Vorticella can also form a cyst to survive
  extended times of poor conditions.
• Note, the stalk is still attached.

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Ciliates-Stalked Ciliates

• Reproduction is always occurring and it is only a
  concern if there is a sudden increase.
• Why it is important to observe your MLSS on a
  regular basis.

Epistylis cell dividing
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Ciliates-Stalked Ciliates

• Vaginicola has a sheath around the body and does
  not appear to have a stalk.
• Good conditions.

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Look like stalked ciliates-but arent!

• Suctorians
• Feed on other protozoa.
• This one is feeding on a vorticella telotroch.
• If lots of protozoalots of suctorians.

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Suctorians

• Do have a stalk that is attached to substrate,
  cannot contract.
• Have tentacles instead of cilia.
• Mostly feed on ciliates.

Numerous suctorians, using an Epistylis colony as
the substrate!
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Summary

• Get to know your activated sludge microbes.
• Get use to using your microscope!
• Observe on a regular basis.
• Develop a way to record observations.

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Summary

• Develop a routine way to observe.
• Practice using the microscope on a regular basis.
• Look at known stuff first, like TP, dirt.
• Look at big picture, first.
• Assess the floc condition.
• Assess the filaments occurrence and type.
• Look at the diversity of microbes.
• Record your observations.
• Relate them to the operational status of your
  plant.

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Summary

• Wastewater treatment is about creating Utopia
  for the sludge bugs!

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Summary

• Why do we do this?
• Dont want to go out to a creek or river and see
  scenes like this..

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Summary

• We want clean water for allboth us and the rest
  of the organisms we share this planet with!

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