Waste water treatment processes Phosphorus is the major agent triggering eutrophication (algeal blooms) in freshwaters. Nitrogen is considered the main element triggering eutrophication in saltwater

1. 1
NORWEGIAN
UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
Department
of
Plant
and
Environmental
Sciences
P.D.
Jenssen
1
Water treatment processes
Petter D. Jenssen and Manoj Pandey**
• Professor, Norwegian University of Life Sciences (UMB)
** Assistant professor, Tribhuvan University, Nepal
THT282 Introduction to sustainable water and sanitation

2. 2
NORWEGIAN
UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
Department of Plant and
Environmental Sciences
7
90% of the worlds wastewater does
not receive any treatment (Corcoran et al. 2010)
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

3. 3
NORWEGIAN
UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
Department
of
Plant
and
Environmental
Sciences
P.D.
Jenssen
3
Phosphorus is the major agent triggering
eutrophication (algeal blooms) in freshwaters

4. 4
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The North Sea
Photo: R. Gjørven
Nitrogen is considered the main
element triggering eutrophication in
saltwater

5. 5
NORWEGIAN
UNIVERSITY
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www.umb.no
Department
of
Plant
and
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P.D.
Jenssen
5
Green algae in a stream in
Norway at 1200 meters altitude

6. 6
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Department
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P.D.
Jenssen
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Nitrogen can cause algea
growth in freshwater in
alpine regions

7. 7
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UNIVERSITY
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Department
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P.D.
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 DO less than 1 mg/l
 BOD - 250 mg
Kathmandu, Nepal
Dry season:
(Pandey et al. 2005)

8. 8
NORWEGIAN
UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
Department
of
Plant
and
Environmental
Sciences
P.D.
Jenssen
8
 DO less than 1 mg/l
 BOD - 250 mg
Kathmandu, Nepal
Dry season:
(Pandey et al. 2005)
Putrification

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Wastewater
treatment -
removal parameters
The objectives of sewage treatment will always
include the reduction of the concentration of at least
one of the below constituents:
Suspended solids;
Organic (biodegradable) material;
Nutrients (nitrogen and phosphorous);
Pathogenic organisms (expressed as E. Coli)
Medicine residues, organic chemicals (POP´s)
Heavy metals
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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Methods of Removal
The contaminants in wastewater are removed by different
unit processes:
 Physical (sedimetation, flotation, screening, filtration)
 Biological (trickling filters, RBC, activated sludge)
 Chemical (chemical precipitation, ozonation, chlorination)
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen
11
Wastewater Treatment –
Processes
Primary Secondary Tertiarary
Sludge treatment
Remove
organics and
ammonia
Remove
nutrients and
pathogens

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Methods of Removal
Physical Unit Processes (mainly primary)
Treatment methods in which the application of physical forces
predominates are known as physical unit operations. Typical unit
operations are:
– Screening
– Sedimentation
– Floatation
– Membrane filtration* (< 1um)
*Tertiary treatment
Salsnes
filter
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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Membrane Filter Technology (tertiary)
Sette inn egne bilder av membraner
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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Membrane Filter Technology
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen
16
Wastewater Treatment –
Processes
Primary Secondary Tertiarary
Sludge treatment
Remove
organics and
ammonia
Remove
nutrients and
pathogens

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OF
LIFE
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Methods of Removal (Contd.)
Biological Unit Processes (mainly secondary)
The treatment method in which the removal of contaminants is
brought about by biological activity are known as biological unit
process. Some examples are:
– aerobic processes - presence of dissolved oxygen
• Biofilters
• Trickling filters
• Activated sludge
– anaerobic processes – absence of dissolved oxygen
• Denitrification (tertiary)
• Septic tanks
• Ponds
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

18. Biofilter
Porous media
LWA
Diam: 2,5 mm
Surface area
> 5000m2/m3
Bacteria on
LWA
surface

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Wastewater spraying over a biofilter
19
Department
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P.D.
Jenssen

20. 20
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Biofilter: trickling filter (fixed biofilm)
20
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

21. 21
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Biofilter: Rotating biological
contactor - RBC (fixed biofilm)
21
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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Activated sludge at Ryaverket Gothenburg
700 000 pe
Department
of
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P.D.
Jenssen
Biological treatment: Activated sludge
(biofilm in suspension)

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Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen
23
Wastewater Treatment -
Processes
Primary Secondary Tertiarary
Sludge treatment
Remove
organics and
ammonia
Remove
nutrients and
pathogens

24. NORWEGIAN
UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
24
Methods of Removal (Contd.)
Chemical Unit Process (tertiary)
Treatment methods in which the removal or conversion of
contaminants is brought about by the addition of chemicals or by
chemical reactions are known as chemical unit processes. Some of
the most common are:
– Precipitation (lime, Fe- of Al salts, Struvite formation)
– Adsorption
– Disinfection
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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UNIVERSITY
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SCIENCES
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25
Methods of Removal (Contd.)
Chemical Unit Process (tertiary)
Treatment methods in which the removal or conversion of
contaminants is brought about by the addition of chemicals or by
chemical reactions are known as chemical unit processes. Some of
the most common are:
– Precipitation
– Adsorption (Ion exchange)
– Disinfection
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

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UNIVERSITY
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SCIENCES
www.umb.no
26
Methods of Removal (Contd.)
Chemical Unit Process (tertiary)
Treatment methods in which the removal or conversion of
contaminants is brought about by the addition of chemicals or by
chemical reactions are known as chemical unit processes. Some of
the most common are:
– Precipitation
– Adsorption
– Disinfection (chlorination, UV-light, Ozone)
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

27. NORWEGIAN
UNIVERSITY
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27
Water and sludge treatment process at
Bekkelaget
Primary sludge Buffertank
Buffer
Silo
Silo
Bio sludge
Dewatering
Thickener
Digester
Digester
Biogas
Overflow
Magasin~35.000m3
4000 l/s < Q < 6000 l/s
Sand, grit and
screenings FeSO4
PAX-18
Activated
sludge
Clarifier
Primary Filter
Precipitation
Primary
1900 l/s<Q< 4000 l/s
Q=1900 l/s
PAX-18
Q<1900 l/s
Biogas-
upgrading
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen

28. 28
NORWEGIAN
UNIVERSITY
OF
LIFE
SCIENCES
www.umb.no
Department
of
Plant
and
Environmental
Sciences,
P.D.
Jenssen
Removal efficiency %
28
Parameter Primary Secondary Tertiary
SS 50 - 80 80 - 90 >90
BOD 20 - 40 70 - 90 >90
P <10 30 >90
N <10 30 70
E. Coli 1 log 2 -3 log 3 - 5 (7)* logs
*with disinfection