SlideShare a Scribd company logo
Activated Sludge
Process
MOHAMED ASFAK
1288
SYBSc (Microbiology)
1
2
After primary treatment- the greater part of BOD remains in the form of dissolved
organic matter
Secondary treatment:
Predominantly biological process
Designed to remove most of the organic matter
Reduce the BOD
Sewage water undergoes strong aeration to
encourage the growth of aerobic bacteria
and other microorganisms that oxidize the
dissolved organic matter to carbon dioxide
and water
Commonly used method for Secondary treatment:
1. Activated sludge process
2. Trickling filters
3
4
5
ACTIVATED SLUDGE PROCESS
Practice of adding some of the sludge from the previous batch to the incoming
sewage
Inoculum is termed as activated sludge because it contains large number of sewage
metabolizing microbes
Activity of aerobic microbes- oxidizes much of the organic matter in to CO2 and H2O
(mainly Zoogloea sp)
Which form bacteria containing masses in aeration tank called floc or sludge
Soluble organic matter in the sewage is incorporated into the floc and its
microorganisms. Aeration is discontinued after 4 to 8 hours
6
7
Settling tank..
Where floc settles out, removing much organic matters. Then these are treated in an
anaerobic sludge digester
Probably more organic matter is removed by this settling out process than by the
relatively short term aerobic oxidation by microbes.
Clear effluent is disinfected and discharged.
Activated sludge process is quite efficient and remove 75-95%
of the BOD from sewage
8
Bulking:
Sludge floats rather than settle out
When this happens, organic matter in the floc flows out with the discharge effluent,
resulting in local pollution.
Caused by the growth of filamentous bacteria of various type; Sphaerotilus natans
and Nacordia sp
Filamentous bulking activated
sludge floc
Pin point floc
9
To avoid sludge bulking some of the flow that enters the reactor can be bypassed,
recycle ratio can be increased, lime or soda can be added to the reactor or the re-
aeration rate increased.

More Related Content

What's hot

Waste water treatment
Waste water treatment  Waste water treatment
Waste water treatment
Ghassan Hadi
 
Activated sludge process
Activated sludge processActivated sludge process
Activated sludge process
Akepati S. Reddy
 
ANAEROBIC SLUDGE DIGESTION PROCESS
ANAEROBIC SLUDGE DIGESTION PROCESSANAEROBIC SLUDGE DIGESTION PROCESS
ANAEROBIC SLUDGE DIGESTION PROCESS
মোঃ গোলাম সারোয়ার
 
L 24 Activated Sludge Process
L 24 Activated Sludge ProcessL 24 Activated Sludge Process
L 24 Activated Sludge Process
Dr. shrikant jahagirdar
 
wastewater treatment
wastewater treatmentwastewater treatment
wastewater treatment
Ezhilmathi S
 
Biological treatment of waste water
Biological treatment of waste waterBiological treatment of waste water
Biological treatment of waste waterShaswati Saha
 
Activated sludge process
Activated sludge processActivated sludge process
Activated sludge process
Shilpa Patil
 
Waste water treatment
Waste water treatment  Waste water treatment
Waste water treatment
Ghassan Hadi
 
Waste water treatment
Waste water treatmentWaste water treatment
Waste water treatmentKumar
 
Waste Water Treatment
Waste Water TreatmentWaste Water Treatment
Waste Water Treatment
Dr. Majid Mohiuddin (Hashmi)
 
Sludge treatment and disposal
Sludge treatment and disposalSludge treatment and disposal
Sludge treatment and disposal
Romanus Peter
 
Trickling filter ppt
Trickling filter pptTrickling filter ppt
Trickling filter ppt
Shilpa Patil
 
Charecteristics of wastewater
Charecteristics of wastewaterCharecteristics of wastewater
Charecteristics of wastewater
Venuri Lakshani
 
Waste water treatment
Waste water treatment Waste water treatment
Waste water treatment
Waste water treatmentWaste water treatment
Waste water treatment
Divya Goel
 
Aerated lagoon
Aerated lagoonAerated lagoon
Aerated lagoon
AniketChavan72
 
Treatment of waste from pulp industry
Treatment of waste from pulp industryTreatment of waste from pulp industry
Treatment of waste from pulp industryprarthana mary
 
UNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptx
UNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptxUNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptx
UNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptx
SathishkumarM89
 
Secondary wastewater treatment
Secondary wastewater treatmentSecondary wastewater treatment
Secondary wastewater treatment
Rishaw R T
 
Rotating biological contactor
Rotating biological contactorRotating biological contactor
Rotating biological contactor
Anik Banik
 

What's hot (20)

Waste water treatment
Waste water treatment  Waste water treatment
Waste water treatment
 
Activated sludge process
Activated sludge processActivated sludge process
Activated sludge process
 
ANAEROBIC SLUDGE DIGESTION PROCESS
ANAEROBIC SLUDGE DIGESTION PROCESSANAEROBIC SLUDGE DIGESTION PROCESS
ANAEROBIC SLUDGE DIGESTION PROCESS
 
L 24 Activated Sludge Process
L 24 Activated Sludge ProcessL 24 Activated Sludge Process
L 24 Activated Sludge Process
 
wastewater treatment
wastewater treatmentwastewater treatment
wastewater treatment
 
Biological treatment of waste water
Biological treatment of waste waterBiological treatment of waste water
Biological treatment of waste water
 
Activated sludge process
Activated sludge processActivated sludge process
Activated sludge process
 
Waste water treatment
Waste water treatment  Waste water treatment
Waste water treatment
 
Waste water treatment
Waste water treatmentWaste water treatment
Waste water treatment
 
Waste Water Treatment
Waste Water TreatmentWaste Water Treatment
Waste Water Treatment
 
Sludge treatment and disposal
Sludge treatment and disposalSludge treatment and disposal
Sludge treatment and disposal
 
Trickling filter ppt
Trickling filter pptTrickling filter ppt
Trickling filter ppt
 
Charecteristics of wastewater
Charecteristics of wastewaterCharecteristics of wastewater
Charecteristics of wastewater
 
Waste water treatment
Waste water treatment Waste water treatment
Waste water treatment
 
Waste water treatment
Waste water treatmentWaste water treatment
Waste water treatment
 
Aerated lagoon
Aerated lagoonAerated lagoon
Aerated lagoon
 
Treatment of waste from pulp industry
Treatment of waste from pulp industryTreatment of waste from pulp industry
Treatment of waste from pulp industry
 
UNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptx
UNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptxUNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptx
UNIT-V- SLUDGE TREATMENT AND DISPOSAL.pptx
 
Secondary wastewater treatment
Secondary wastewater treatmentSecondary wastewater treatment
Secondary wastewater treatment
 
Rotating biological contactor
Rotating biological contactorRotating biological contactor
Rotating biological contactor
 

Similar to Activated sludge process in wastewater treatment plant

Biological wastewater treatment
Biological wastewater treatmentBiological wastewater treatment
Biological wastewater treatment
ssuserad8df0
 
CONVENTIONAL METHOD – WASTE WATER TREATMENT.pptx
CONVENTIONAL METHOD – WASTE WATER TREATMENT.pptxCONVENTIONAL METHOD – WASTE WATER TREATMENT.pptx
CONVENTIONAL METHOD – WASTE WATER TREATMENT.pptx
College of Fisheries, Mangalore
 
Liquid waste management
Liquid waste managementLiquid waste management
Liquid waste managementjijeesh4593
 
Use of biotechnology in the treatment of municipal wastes and hazardousindust...
Use of biotechnology in the treatment of municipal wastes and hazardousindust...Use of biotechnology in the treatment of municipal wastes and hazardousindust...
Use of biotechnology in the treatment of municipal wastes and hazardousindust...
Sijo A
 
Waste treatment
Waste treatmentWaste treatment
Waste treatment
PurushotamRay
 
Biotechnology in Industrial Waste water Treatment
Biotechnology in Industrial Waste water TreatmentBiotechnology in Industrial Waste water Treatment
Biotechnology in Industrial Waste water Treatmentshuaibumusa2012
 
Treatment of water
Treatment of waterTreatment of water
Treatment of water
Aditi122
 
Flotation presentation
Flotation presentationFlotation presentation
Flotation presentation
Авдуллахи Назифи
 
Dairy Effluent Treatment
Dairy Effluent TreatmentDairy Effluent Treatment
Dairy Effluent Treatment
JayeshDhoral
 
Industrial waste water purification procedure
Industrial waste water purification procedureIndustrial waste water purification procedure
Industrial waste water purification procedure
pasindulaksara1
 
Effluent treatment plant
Effluent treatment plantEffluent treatment plant
Effluent treatment plant
Sahil Gohad
 
Biological Basis of Wastewater Treatment.pptx
Biological Basis of Wastewater Treatment.pptxBiological Basis of Wastewater Treatment.pptx
Biological Basis of Wastewater Treatment.pptx
NevinYagci1
 
Biological treatment of waste water
Biological treatment of waste waterBiological treatment of waste water
Biological treatment of waste water
AarjavPinara
 
ADVANCED METHOD FOR WASTE WATER TREATMENT.pptx
ADVANCED METHOD FOR WASTE WATER TREATMENT.pptxADVANCED METHOD FOR WASTE WATER TREATMENT.pptx
ADVANCED METHOD FOR WASTE WATER TREATMENT.pptx
Sakshi Patil
 
PPT for Excreta disposal.ppt
PPT for  Excreta disposal.pptPPT for  Excreta disposal.ppt
PPT for Excreta disposal.ppt
Vanithadurai
 
Treatments of sewage, sludge and polluted water
Treatments of sewage, sludge and polluted waterTreatments of sewage, sludge and polluted water
Treatments of sewage, sludge and polluted water
halamobeen
 
Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)
Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)
Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)
Nitish Sharma
 
Conventional Wastewater Treatment PROCESS.pdf
Conventional Wastewater Treatment PROCESS.pdfConventional Wastewater Treatment PROCESS.pdf
Conventional Wastewater Treatment PROCESS.pdf
AMIT820413
 
Biotechnology in microbiology
Biotechnology in microbiologyBiotechnology in microbiology
Biotechnology in microbiology
Duithy George
 

Similar to Activated sludge process in wastewater treatment plant (20)

Biological wastewater treatment
Biological wastewater treatmentBiological wastewater treatment
Biological wastewater treatment
 
CONVENTIONAL METHOD – WASTE WATER TREATMENT.pptx
CONVENTIONAL METHOD – WASTE WATER TREATMENT.pptxCONVENTIONAL METHOD – WASTE WATER TREATMENT.pptx
CONVENTIONAL METHOD – WASTE WATER TREATMENT.pptx
 
Liquid waste management
Liquid waste managementLiquid waste management
Liquid waste management
 
Use of biotechnology in the treatment of municipal wastes and hazardousindust...
Use of biotechnology in the treatment of municipal wastes and hazardousindust...Use of biotechnology in the treatment of municipal wastes and hazardousindust...
Use of biotechnology in the treatment of municipal wastes and hazardousindust...
 
Waste treatment
Waste treatmentWaste treatment
Waste treatment
 
Biotechnology in Industrial Waste water Treatment
Biotechnology in Industrial Waste water TreatmentBiotechnology in Industrial Waste water Treatment
Biotechnology in Industrial Waste water Treatment
 
Activated Sludge Process
Activated Sludge ProcessActivated Sludge Process
Activated Sludge Process
 
Treatment of water
Treatment of waterTreatment of water
Treatment of water
 
Flotation presentation
Flotation presentationFlotation presentation
Flotation presentation
 
Dairy Effluent Treatment
Dairy Effluent TreatmentDairy Effluent Treatment
Dairy Effluent Treatment
 
Industrial waste water purification procedure
Industrial waste water purification procedureIndustrial waste water purification procedure
Industrial waste water purification procedure
 
Effluent treatment plant
Effluent treatment plantEffluent treatment plant
Effluent treatment plant
 
Biological Basis of Wastewater Treatment.pptx
Biological Basis of Wastewater Treatment.pptxBiological Basis of Wastewater Treatment.pptx
Biological Basis of Wastewater Treatment.pptx
 
Biological treatment of waste water
Biological treatment of waste waterBiological treatment of waste water
Biological treatment of waste water
 
ADVANCED METHOD FOR WASTE WATER TREATMENT.pptx
ADVANCED METHOD FOR WASTE WATER TREATMENT.pptxADVANCED METHOD FOR WASTE WATER TREATMENT.pptx
ADVANCED METHOD FOR WASTE WATER TREATMENT.pptx
 
PPT for Excreta disposal.ppt
PPT for  Excreta disposal.pptPPT for  Excreta disposal.ppt
PPT for Excreta disposal.ppt
 
Treatments of sewage, sludge and polluted water
Treatments of sewage, sludge and polluted waterTreatments of sewage, sludge and polluted water
Treatments of sewage, sludge and polluted water
 
Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)
Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)
Primary, secondary and tertiary treatments in ETP (Effluent Treatment Plant)
 
Conventional Wastewater Treatment PROCESS.pdf
Conventional Wastewater Treatment PROCESS.pdfConventional Wastewater Treatment PROCESS.pdf
Conventional Wastewater Treatment PROCESS.pdf
 
Biotechnology in microbiology
Biotechnology in microbiologyBiotechnology in microbiology
Biotechnology in microbiology
 

Recently uploaded

Structural Classification Of Protein (SCOP)
Structural Classification Of Protein  (SCOP)Structural Classification Of Protein  (SCOP)
Structural Classification Of Protein (SCOP)
aishnasrivastava
 
Unveiling the Energy Potential of Marshmallow Deposits.pdf
Unveiling the Energy Potential of Marshmallow Deposits.pdfUnveiling the Energy Potential of Marshmallow Deposits.pdf
Unveiling the Energy Potential of Marshmallow Deposits.pdf
Erdal Coalmaker
 
Richard's aventures in two entangled wonderlands
Richard's aventures in two entangled wonderlandsRichard's aventures in two entangled wonderlands
Richard's aventures in two entangled wonderlands
Richard Gill
 
Lab report on liquid viscosity of glycerin
Lab report on liquid viscosity of glycerinLab report on liquid viscosity of glycerin
Lab report on liquid viscosity of glycerin
ossaicprecious19
 
Viksit bharat till 2047 India@2047.pptx
Viksit bharat till 2047  India@2047.pptxViksit bharat till 2047  India@2047.pptx
Viksit bharat till 2047 India@2047.pptx
rakeshsharma20142015
 
Richard's entangled aventures in wonderland
Richard's entangled aventures in wonderlandRichard's entangled aventures in wonderland
Richard's entangled aventures in wonderland
Richard Gill
 
NuGOweek 2024 Ghent - programme - final version
NuGOweek 2024 Ghent - programme - final versionNuGOweek 2024 Ghent - programme - final version
NuGOweek 2024 Ghent - programme - final version
pablovgd
 
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
Sérgio Sacani
 
Anemia_ different types_causes_ conditions
Anemia_ different types_causes_ conditionsAnemia_ different types_causes_ conditions
Anemia_ different types_causes_ conditions
muralinath2
 
Large scale production of streptomycin.pptx
Large scale production of streptomycin.pptxLarge scale production of streptomycin.pptx
Large scale production of streptomycin.pptx
Cherry
 
insect morphology and physiology of insect
insect morphology and physiology of insectinsect morphology and physiology of insect
insect morphology and physiology of insect
anitaento25
 
Comparative structure of adrenal gland in vertebrates
Comparative structure of adrenal gland in vertebratesComparative structure of adrenal gland in vertebrates
Comparative structure of adrenal gland in vertebrates
sachin783648
 
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
Sérgio Sacani
 
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
NathanBaughman3
 
Multi-source connectivity as the driver of solar wind variability in the heli...
Multi-source connectivity as the driver of solar wind variability in the heli...Multi-source connectivity as the driver of solar wind variability in the heli...
Multi-source connectivity as the driver of solar wind variability in the heli...
Sérgio Sacani
 
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
Health Advances
 
GBSN- Microbiology (Lab 3) Gram Staining
GBSN- Microbiology (Lab 3) Gram StainingGBSN- Microbiology (Lab 3) Gram Staining
GBSN- Microbiology (Lab 3) Gram Staining
Areesha Ahmad
 
platelets_clotting_biogenesis.clot retractionpptx
platelets_clotting_biogenesis.clot retractionpptxplatelets_clotting_biogenesis.clot retractionpptx
platelets_clotting_biogenesis.clot retractionpptx
muralinath2
 
Nutraceutical market, scope and growth: Herbal drug technology
Nutraceutical market, scope and growth: Herbal drug technologyNutraceutical market, scope and growth: Herbal drug technology
Nutraceutical market, scope and growth: Herbal drug technology
Lokesh Patil
 
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCINGRNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
AADYARAJPANDEY1
 

Recently uploaded (20)

Structural Classification Of Protein (SCOP)
Structural Classification Of Protein  (SCOP)Structural Classification Of Protein  (SCOP)
Structural Classification Of Protein (SCOP)
 
Unveiling the Energy Potential of Marshmallow Deposits.pdf
Unveiling the Energy Potential of Marshmallow Deposits.pdfUnveiling the Energy Potential of Marshmallow Deposits.pdf
Unveiling the Energy Potential of Marshmallow Deposits.pdf
 
Richard's aventures in two entangled wonderlands
Richard's aventures in two entangled wonderlandsRichard's aventures in two entangled wonderlands
Richard's aventures in two entangled wonderlands
 
Lab report on liquid viscosity of glycerin
Lab report on liquid viscosity of glycerinLab report on liquid viscosity of glycerin
Lab report on liquid viscosity of glycerin
 
Viksit bharat till 2047 India@2047.pptx
Viksit bharat till 2047  India@2047.pptxViksit bharat till 2047  India@2047.pptx
Viksit bharat till 2047 India@2047.pptx
 
Richard's entangled aventures in wonderland
Richard's entangled aventures in wonderlandRichard's entangled aventures in wonderland
Richard's entangled aventures in wonderland
 
NuGOweek 2024 Ghent - programme - final version
NuGOweek 2024 Ghent - programme - final versionNuGOweek 2024 Ghent - programme - final version
NuGOweek 2024 Ghent - programme - final version
 
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...
 
Anemia_ different types_causes_ conditions
Anemia_ different types_causes_ conditionsAnemia_ different types_causes_ conditions
Anemia_ different types_causes_ conditions
 
Large scale production of streptomycin.pptx
Large scale production of streptomycin.pptxLarge scale production of streptomycin.pptx
Large scale production of streptomycin.pptx
 
insect morphology and physiology of insect
insect morphology and physiology of insectinsect morphology and physiology of insect
insect morphology and physiology of insect
 
Comparative structure of adrenal gland in vertebrates
Comparative structure of adrenal gland in vertebratesComparative structure of adrenal gland in vertebrates
Comparative structure of adrenal gland in vertebrates
 
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
 
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
 
Multi-source connectivity as the driver of solar wind variability in the heli...
Multi-source connectivity as the driver of solar wind variability in the heli...Multi-source connectivity as the driver of solar wind variability in the heli...
Multi-source connectivity as the driver of solar wind variability in the heli...
 
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
 
GBSN- Microbiology (Lab 3) Gram Staining
GBSN- Microbiology (Lab 3) Gram StainingGBSN- Microbiology (Lab 3) Gram Staining
GBSN- Microbiology (Lab 3) Gram Staining
 
platelets_clotting_biogenesis.clot retractionpptx
platelets_clotting_biogenesis.clot retractionpptxplatelets_clotting_biogenesis.clot retractionpptx
platelets_clotting_biogenesis.clot retractionpptx
 
Nutraceutical market, scope and growth: Herbal drug technology
Nutraceutical market, scope and growth: Herbal drug technologyNutraceutical market, scope and growth: Herbal drug technology
Nutraceutical market, scope and growth: Herbal drug technology
 
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCINGRNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
 

Activated sludge process in wastewater treatment plant

  • 2. 2
  • 3. After primary treatment- the greater part of BOD remains in the form of dissolved organic matter Secondary treatment: Predominantly biological process Designed to remove most of the organic matter Reduce the BOD Sewage water undergoes strong aeration to encourage the growth of aerobic bacteria and other microorganisms that oxidize the dissolved organic matter to carbon dioxide and water Commonly used method for Secondary treatment: 1. Activated sludge process 2. Trickling filters 3
  • 4. 4
  • 5. 5 ACTIVATED SLUDGE PROCESS Practice of adding some of the sludge from the previous batch to the incoming sewage Inoculum is termed as activated sludge because it contains large number of sewage metabolizing microbes Activity of aerobic microbes- oxidizes much of the organic matter in to CO2 and H2O (mainly Zoogloea sp) Which form bacteria containing masses in aeration tank called floc or sludge Soluble organic matter in the sewage is incorporated into the floc and its microorganisms. Aeration is discontinued after 4 to 8 hours
  • 6. 6
  • 7. 7 Settling tank.. Where floc settles out, removing much organic matters. Then these are treated in an anaerobic sludge digester Probably more organic matter is removed by this settling out process than by the relatively short term aerobic oxidation by microbes. Clear effluent is disinfected and discharged. Activated sludge process is quite efficient and remove 75-95% of the BOD from sewage
  • 8. 8 Bulking: Sludge floats rather than settle out When this happens, organic matter in the floc flows out with the discharge effluent, resulting in local pollution. Caused by the growth of filamentous bacteria of various type; Sphaerotilus natans and Nacordia sp Filamentous bulking activated sludge floc Pin point floc
  • 9. 9 To avoid sludge bulking some of the flow that enters the reactor can be bypassed, recycle ratio can be increased, lime or soda can be added to the reactor or the re- aeration rate increased.