wama 2 water purification
DESCRIPTION
descripcion de procesos de purificacion del aga, documento en inglésTRANSCRIPT
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Department of Hydro Sciences, Institute for Urban Water Management
UNEP Course CIPSEM Dresden, September 2014
Water Management and Climate Change Adaptation
2 Water extraction and purification
Peter Krebs
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 2
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
-
UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 3
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 4
Sufficient Drinking Water of good Quality at any Time
Political decision making
sufficient how much, how long during dry periods ?
good quality hygiene, to be drunk, for toilet flushing, how long ?
any time extreme drought, contaminated water spring
Task of water supply
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 5
Implementation via guidelines, threshold values
DIN 2000
Drinking water should be appetizing and tempting, colourless, clear, cold, odourless, and perfectly fresh with regard to taste.
Drinking water quality
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 6
Ground water
Storage
Industry
Settlement
Lake, dam
Water protection
Tight construction
Protection zone
Pressure
Saftey barriers
Spring intake
Protection zone
Purification
Water distribution
Structure of a water supply system
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 7
Regional water supply systems in Germany
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 8
Type of water supply Typical consumption
l/(Cad)
Rangel/(Cad)
Communal water pointdistance > 1000 m distance 250 1000 m
712
5 1010 15
Village well distance < 250 m 20 15 25
Communal standpipe distance < 250 m 30 20 50
Yard connection 40 20 80
House connection single tapmultiple tap
50150
30 6070 250
System dependent water consumption
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 9
Drinking water consumption in Germany
116
133
112
98
127133
123
100
128135
118 116
8590
133
90
122
0
20
40
60
80
100
120
140
160
Bade
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 10
28%
34%
12%
6%6%
6% 4% 2%2%
28% WC34% bathing/shower12% washing cloths6% personal hygiene6% wash dishes6% cleaning4% watering2% cooking/drinking2% cleaning cars
Drinking water consumption of private households
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 11
Qd average daily consumption over a year
Qh average hours consumption at average day
Qd,max maximum daily consumption of a year
Qh,max maximum hours consumption at maximums day
fd Peak days factor
fh Peak hours factor
Parameters to characterise consumption (i)
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 12
Parameter Decisive for
Maximum daily water needQd,max = fd Qd
Purification, reservoir
Average hourly need at average day Qh = Qd / 24
Maximum hours need at maximum day Qh,max = fh Qd / 24
Distribution system
Parameters to characterise consumption (ii)
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 13
Drinking water prices for centralised systems
2,18
1,761,65 1,63
1,261,16
1,000,94
0,81 0,76 0,750,68 0,67
0,52
0,00
0,50
1,00
1,50
2,00
2,50
Denm
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Belgi
um
Fran
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Austr
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Italy
Finlan
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Spain
South
Afric
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Cana
da USA
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 14
Drinking water prices in Germany
1,81
1,27
2,29
1,51
1,98
1,52
1,93
1,55
1,19
1,59 1,55
1,81,93
1,57
1,3
2,04
1,6
0,00
0,50
1,00
1,50
2,00
2,50
Bade
n-Wrt
tembe
rg Ba
yern
Berlin
Br
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nburg
Br
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Ha
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He
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Meck
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rg-Vo
rpomm
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Niede
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Nordr
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Wes
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Rh
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d-Pfal
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d Sa
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 15
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 16
pH-value:
Ferric (Fe):
Manganese (Mn):
5 6,5
1 10 mg/l
0,2 1 mg/l
Oxygen (O2): < 1 mg/l
Typical ranges:
Additional anthropogenic loads:
Agriculture: Nitrate (NO3-), pesticides
Industry (Air and wastewater):
Organic compounds, ammonia, acid rain dissolution of metals (e.g. aluminium)
Characteristics of groundwater
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 17
Geology LocationpH O2 Fe Mn KB 8,2
Hard-ness KS 4,3
mg/l mg/l mg/l mol/m3 dH mol/m3
Crystalline Gotteszell 6,0 10,8 0,3 0,6 0,1
Sandstone Heldmann-berg 7,3 0,5 0,3 0,04 1,2 18,9 6,3
Pleistozene
Tettau 5,7...7,1 n.n.152
50,10,
8 1,0... 2,56,0...12
,10,15...1,25
Spremberg 5,3 0,02 7,5 0,15 1,6 5,1 0,14
Engelsdorf 2 (Leipzig) 7,2 1,0 7,6 0,54 0,88 42,9 4,48
Lommatzsch 7,2 < 0,5 7,5 0,5 1,61 36,6 8,21
Gravel Munich 7,2 10,5 0,01 0,43 14,3 4,4
Ground and spring water
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 18
Parameter Unit Wahnbach (Siegelsknippen)
Klingenberg (Coschtz)
Muldenberg(Muldenberg)
Temperature C 3,86,7 4,014,5 0,712,8
pH-value 6,8...7,1 6,6...7,7 4,3...4,9
Oxygen mg/l 5,9...11,1 7,8...12,3 5,8...12,9
DOC mg/l 0,48...1,27 2,2...2,6 2,0
SAC 436 nm m-1 0,06...0,08 0,14...0,46 < 0,1...0,4
Turbidity TE/F 0,48...1,27 0,3...1,8 0,43...2,5
AOX mg/l < 0,01 < 0,01...0,018 < 0,0015
KS 4,3 mol/m 0,43...0,50 0,15...0,4 0,01...0,03
Hardness mol/m 0,7...0,8 0,5...0,7 0,17...0,19
Aluminium mg/l 0,02...0,27 < 0,02...0,16 0,62...0,96
Nitrate mg/l 16...17 12...19 2,0...3,6
Ferric, total mg/l < 0,01...0,03 < 0,05...0,12 < 0,17...0,60
Manganese mg/l 0,01...0,19 0,024...0,14 0,48...0,59
Arsenic g/l < 0,5 1,0...2,9 < 1,0
Colonies no. at 20 C ml-1 22...1490 0... > 1000 0...528
Coliformes 1/100 ml 0...12 0 0
Water of a dam
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 19
Parameter Unit Elbe(Hosterwitz)
Donau at LeipheimMean 2001
Temperature C 0,622,5 10,4
pH-value 7,3...8,6 8,12
Oxygen mg/l 4,4...11,8 10,51
DOC mg/l 4,6...6,6 2,85
SAC 436 nm m-1 0,65...1,9 n.b.
Turbidity TE/F 34...140 8,48
AOX mg/l 0,022...0,199 0,012
KS 4,3 mol/m 1,2...2,15 4,27
Hardness mol/m 1,4...2,1 2,5
Aluminium mg/l 0,025...0,82 0,04
Nitrate mg/l 16...30 13,7
Ferric mg/l 0,25...4,4 0,02
Manganese mg/l < 0,02...0,51 < 0,0050
Arsenic g/l 2,5...3,3 0,00014
Colonies no. at 20 C ml-1 1000... > 168 000 5651
Coliforms 1/100 ml > 2400 13393
River water
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 20
Parameter Unit Lake of Constance (60 m depth)Mean 2000
Temperature C 5,1
pH-value 8,05
Oxygen mg/l 10,6
DOC mg/l 1,3
SAC 254 nm m-1 3,1
SAC 436 nm m-1 Not detectable
Turbidity FNU 0,51
AOX mg/l 0,006
KS 4,3 mol/m 2,52
KB 8,2 mol/m 0,03
Hardness dH 8,97
Aluminium mg/l 0,0085
Nitrate mg/l 4,5
Ferric mg/l 0,010
Manganese mg/l 0,0009
Arsenic mg/l 0,0013
Lake water
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 21
Parameter River water Bank filtrate
Coliforms < 29.000 < 640 (per 100 ml)
E. Coli < 2.000 < 4 (pro 100 ml)
Temperature 3,5 23,4 9,7 16,5 (C)
O2 10,1 5,2 (g/m3)
CO2 2,3 6,5 (g/m3)
NH4+-N < 0,055 < 0,016 (g/m3)
Biomass < 7 < 0,02 (g/m3)
River bank filtrate
typical values from Zurich
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 22
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 23
Often good quality and relatively simple purification
Aquifer is a large storage unit and levels out variations in extraction
Supporting filter layers against wash-out of sand from neighbouring ground
The smaller the wells diameter, the more serious is the danger silting up
Maintenance against clogging
Characteristics of groundwater
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 24
Undisturbed GW-level
QW
concentric flow
Rain
Impervious ground
Water extraction: filter well
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 25
Natural ground
Steel filter pipe Supporting sand- and gravel layers
Filter pipe with supporting layers
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 26
Horizontal intake
QW
Undisturbed GW-table
Horizontal filter well
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 27
Infiltration Collection shaft
Overflow Aquifer
Spring water abstraction
Spring water extraction
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 28
Buchbrunnenquelle (Foto von Steinmetz, M.)
Spring water intake
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 29
Dam with multiple intake
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 30
Intake with Fish screen30 - 60 m deep10 m above ground
Raw waterpumping station
Sediments,Partly loose
Rock
Lake water intake
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 31
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 32
Export of CO2, for de-acidification
Export (purging) of volatile substances, such as H2S, CH4
Stripping of volatile organic compounds
Import of oxygen for oxidation of dissolved compounds (e.g. ferric substances, manganese, ammonia) and to improve taste and development of protection layers
Introduction of ozone
Goals of gas transfer
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 33
HENRY-DALTON law cS = cGcS Gas saturation concentration in water cG Gas concentration in air Solubility coefficient = f (t, pG)
Import flux
ccDF Sin Export flux
ccDF Sex ccS ccS
Transfer process description
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 34
( Aquadosil)
Aeration with free surface
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 35
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 36
Turbid raw water
Pre-treated water
Drinking water
Removal of particles
Enhanced treatment, stabilisation, disinfection
Two major steps of water purification
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 37
Rack only with surface waters wide and narrow slots
Micro sieves Steel or textile grid size < 0,1 mm, continuous back rinsing
Raw water Clear water tank Effluent Micro sieve Rotating cylinder Rinsing Driver, controlled
Removal of coarse particles
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 38Source: Bodenseewasserversorgung
Micro sieve
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 39
0.1
10
1000
10-5 10-3 10-1 10
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Particle size (mm)
Flocculation
Filtration
Sedimentation
Sieves
Rack
Viruses Bacteria Algae
Processes to remove particles
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 40
Mixing Flocculation Separation
Sludge Treatment
Flocculant
De-stabilisation, generation of micro-flocs
Aggregation and generation of macro-flocs
Sedimentation, flotation, filtration
Enhanced treatment
Filtration
ev. flocculation aid
Flocculation
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 41
Q Q
Inlet region Effluent region Sediments Sedimentation region
Length of tank
Sedimentation Length LS
Sedimentation
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 42
often layered (two or more layers) top: coarse, light material (e.g. pumice stone 1,4 2,5 mm)bottom: fine, heavy material (e.g. sand, 0,71 1,25 mm)
hydraulic load 4 30 m/h
Pressure head 2 5 m
Quick increase of resistance an pressure head decrease; clogging of fine material is faster,
Back rinsing with water, air, and water/air
Pressure filtration for smaller filter areas
Fast filtration
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 43
Open fast filter
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 44
Filtrate concentration Filter resistance
Threshold values pcr (hF,cr)
critical filtrate conc. ccr
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Filter operation time tt1 t2
Filtration effect and resistance
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 45
Back rinsing
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 46
Removal of particlesmicrobial loadbio-degradable substances
Sieve effect Adsorptive effect over entire filter depth Mud cover, a few cm, biologically active
Organic compounds are degraded Ammonia is nitrified
Prerequisite O2-concentration is sufficient small TSS-concentration
Surface overflow rate 0,1 0,2 m/h, pressure head ca. 1 m 3 24 months removal of mud cover large area necessary
Slow filtration (i)
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 47
Raw waterFiltration
Mud layer, bio-active !
Sand filter, 0.6 mm, H > 0.5 m
Drainage bottom
Sand filter, layered with increasing diameter towards bottom
Slow filtration (ii)
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 48
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
-
UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 49
Fe2+ Fe3+
Contact with O2
High solubility
Low solubility
Rusty precipitation
Filtration
Manganese
Similar to ferric substances, Oxidation through micro-organisms or catalytic reaction
Removal of Ferric and Manganese
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 50
Removal of dissolved organic compounds
microscopic pores through glowing of coal at 650C, as a significant part is oxidised and volatilised as CO2
huge internal surface: 1000 2000 (m2/g active carbon)
active carbon is sensitive on mechanical stress
rinsing as seldom as possible via pre-treatment and separation of particles before the activated carbon process
Micro-organisms on the surface bio-degradation of organic compounds
Activated carbon adsorption
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 51
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
-
UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 52
CO2 CaCO3
Drinking water treatment Neutralisation
Acid Lime, calcium carbonate
Aggressive, corrosive
Aeration Filtration through lime Adding hydroxides, soda
Precipitation, encrusting
Precipitation Reduction of solubility
Ion exchange
De-acidification
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 53
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 54
KS4,3 KB8,2
Lime carbonic acid system
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 55
2 Water extraction and purification
2.1 Concept, overview
2.2 Raw water composition
2.3 Water extraction
2.4 Gas exchange
2.5 Removal of particles
2.6 Removal of particles and colloids
2.7 Chemical stabilisation
2.8 Disinfection and network protection
Department of Hydro Sciences, Institute for Urban Water Management
Peter Krebs
-
UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 56
Inactivation of pathogenic germs
Chemical oxidation
UV-radiation
O3 fast decay, no by-products, Oxidation
Cl2 cheap, Network safety, reactive
ClO2 Network protection, local production
In 1 cm layer, for some seconds
No by-products
No network protection
Only for small plants, expensive
possibly production of by-products
Disinfection
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UNEP Water and Climate 2 Water extraction and purification PK, 2014 page 57
Oxidation Disinfection long term effect
Chlorine Satisfactory good good
Chlorine dioxide Bad satisfactory satisfactory
Ozone Good good negative
UV-Radiation Bad satisfactory negative
Effect of disinfection means