The World of Activated Sludge
Transcript of The World of Activated Sludge
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IIIINTRODUCTIONNTRODUCTIONNTRODUCTIONNTRODUCTIONOOOOFFFF AAAACTIVATEDCTIVATEDCTIVATEDCTIVATED SSSSLUDGELUDGELUDGELUDGE
� Biological Treatment Process:-
� Use of Microorganisms to break down the organic matter in
wastewater
Suspended-Growth mechanisms
Organic Matter CO2 + H2O + Energy + New BiomassO2
� Suspended-Growth mechanisms:-
� This process maintain a culture of organisms in suspension of
wastewater liquid, either by vigorously aerating the liquid or
by mechanical mixing.
� Aerobic Bacteria grow and form particles that clump together.
� These particles (flocs) are allowed to settle to the bottom of the
clarifier, leaving a relatively clear liquid free of organic material
and suspended solids after aeration process.2
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MicroorganismsMicroorganismsMicroorganismsMicroorganisms
inininin
Activated SludgeActivated SludgeActivated SludgeActivated Sludge
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Activated SludgeActivated SludgeActivated SludgeActivated Sludge
BBBBACTERIAACTERIAACTERIAACTERIA
� Composition:- C60H87O23N12P
� Characteristic:-� Ability to flocculate to form floc and their separation from the liquid phase for complete stabilization.
� Removal of organic matter from wastewater is carried out through 2 process:-
1. Biological Oxidation / Respiration1. Biological Oxidation / Respiration
2. Biosynthesis
� Examples:-� Zooglea, Bacillius spp. , Pseudomonas, Flavobacterium, Alcaligenes, Acinetobacter 5
COHNS + 02 + BACTERIA ���� CO2 + H2O + ENERGY + others
COHNS + O2 + BACTERIA ���� C5H7NO2 (New Cells)
GROWTH OF BACTERIA - HIGH LEVEL OF FOODHIGH LEVEL OF FOODHIGH LEVEL OF FOODHIGH LEVEL OF FOOD
� When abundance of food is
available
� Bacteria are grow, motile, &
extremely active
� They are multiply rapidly.
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� Bacteria will not flocculate and
settle as long as they are growing
at a lag phase.
� Biosynthesis (new cell)����;
Respiration (energy)����
� Activated Sludge with a
poor settling properties
� When low level of food is available
� The bacteria begin to conserve energy & become non-
motile form
� They begin to form a thick outer slime layer. As
they bump into each other, they stick together.
GROWTH OF BACTERIA - LOW LEVEL OF FOODLOW LEVEL OF FOODLOW LEVEL OF FOODLOW LEVEL OF FOOD
they bump into each other, they stick together.
� At first they form small clumps then masses large
enough to settle
� Autoagglutination process
� Biosynthesis (new cell)����;
Respiration (energy) ����
� Activated Sludge with a good settling properties7
FFFFILAMENTOUSILAMENTOUSILAMENTOUSILAMENTOUSBBBBACTERIAACTERIAACTERIAACTERIA
� Characteristic:-
� Filaments do not have the same flocculating characteristics
as the bacteria which do not compact to a readily settleable
mass.
� Roles:-1. BOD/COD removal1. BOD/COD removal
2. Add a backbone for strengthen purpose to the floc structure
� Examples of Filaments:-
� S. natans,
� Nocardia,
� Beggiatoa…
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When filaments abundant in
activated sludge:-� Foaming
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Predominate over the bacteria when:-1. Low Dissolve Oxygen
2. Low pH
3. Low Nutrients
4. F/M ratio not stable
5. High level of Oil & Grease
PPPPROTOZOAROTOZOAROTOZOAROTOZOA
� Roles:-
� Removing & digesting free-swimming dispersed bacteria
and other suspended particles. This improves the clarity of the effluent
� Biological Indicator of the activated sludge condition:-
� Strict Aerobes � Strict Aerobes
� More sensitive to toxic organic compound
� Examples:-
1. Ciliates (Opercularia, Carchesium polypinum …)
2. Amoebae (Arcella,Euglypha…)
3. Flagellates (Peranema… )
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PROTOZOA -AAAAMOEBAEMOEBAEMOEBAEMOEBAE� Food:-
� They feed on small organic particulates
� When abundant present in Activated sludge:-
� Plant start-up.
� A shock load of BOD / large amount of organic � A shock load of BOD / large amount of organic
particulates has entered the treatment system
� They move slowly & cannot compete with bacteria / protozoa for
food. Sudden increase in food allows them to compete & multiply
� They required less O2 & able to
compete with other protozoa
when the O2 is limited.
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� Food:-
� They feed on suspended bacteria, algae & smaller protozoa
� Stalked Ciliate dominance in the system when:-
� Bacterial population and dissolved oxygen concentration of the
treatment process are high
PROTOZOA -SSSSTALKEDTALKEDTALKEDTALKED CILIATECILIATECILIATECILIATE
Stalk
treatment process are high
� A mature floc structure has developed
� They indicate a stable wastewater environment & a healthy
activated sludge
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Examples:-1. Carchesium sp.
2. Suctorian
PROTOZOA -CRAWLING CILIATESCRAWLING CILIATESCRAWLING CILIATESCRAWLING CILIATES
� Food:-
� They feed on suspended bacteria, algae & smaller protozoa
� Characteristic:-
� They are free forms, inhabit the surface of sludge flocs or
biofilmbiofilm
� They dominance in the system when:-
� After most soluble nutrients have been removed which are
reflect a stable wastewater
environment & healthy
activated sludge
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METAZOA
� They are multicellular organisms & include all animals
except the protozoa
� Roles:-
� Feed on bacteria, bacteria floc, fungi, protozoa
& rotifer
Examples:-� Examples:-
� Nematode worms (Genus Aelosoma, Rhabditis)
� Rotifers
� Tartigrades (water bear)
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METAZOA -RRRROTIFEROTIFEROTIFEROTIFER
� Roles:-
� Feed on good, stabilized floc; They graze on the floc
structure and increase oxygen penetration
� As environmental indicator due to they are usually the first
to be affected by a toxic load.
� When abundant present in activated sludge:-
� Old sludge age with high MLSS
� Low F/M ratio
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EVALUATION OF ACTIVATED
SLUDGE
Bacteria Testing Report16
Lab TestingLab
Testing
Routine M
icroscopic
Examination
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Microscopic
Examination
Microscopic
Examination
Routine M
icroscopic
Examination
Big & Compact Floc?
Small & Pin Floc
Condiction?
Dispersed Growth?
Sludge Carry Over
BAD smell
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Foaming?!!!
High COD & High COD & TSS of
Discharge water
Protozoa?
Filaments?
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Rotifer?
Secondary
Clarifier
Secondary
Clarifier
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Final
Discharged
Final
Discharged
Booth L220
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Booth L220i-Chem Solution Sdn Bhd
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