Removal of disinfection by-product precursors by ultrafiltration in the

Faculty of Environmental Sciences
Institute of Urban Water Management, Chair of Water Supply Engineering
Removal of disinfection by-product
precursors by ultrafiltration in the
South-West waterworks in Moscow,
Russia
Alexander Abe, Ekaterina Vasyukova, Wolfgang Uhl
Technische Universität Dresden, Dresden, Germany
Chair of Water Supply Engineering
Demitri Allerdings, Gerrit Förster
WTE Wassertechnik GmbH, Essen, Germany
Contents
1. Natural organic matter in water treatment
2. Moscow South-West waterworks
3. Analytical and experimental methods
4. NOM removal across treatment
5. Trihalomethane formation potential due to
chlorination and chloramination
6. Conclusions
Natural organic matter in water treatment
• Metabolic products of live organisms and
degradation products of biological material
(particulate and dissolved)
• In North-West Russia degradation rates are low,
surface waters drain peat land areas and are
NOM-rich
Natural organic matter in water treatment
Influence on water quality:
•
Aesthetic (taste, odour and colour)
•
Precursor of potentially carcinogenic
disinfection by-products during disinfection
•
Energy source for bacterial growth  regrowth
in distribution systems
Natural organic matter in water treatment
Influence on water treatment:
•
Membrane fouling
•
Poor particle separation during coagulation
•
Reduced adsorptive capacity of activated
carbon
Motivation
•
There is still a gap between theoretical/batch studies
and practice
•
Theoretically optimal conditions are not always
achievable during full-scale operation
Objectives:
• Evaluate the effectiveness of ultrafiltration
and its pre-treatment to remove NOM and
trihalomethane formation potential (THMFP)
• Identify optimisation potentials of single
processes with regard to NOM removal in
waterworks
Moscow South-West waterworks
• Commissioned in December 2006 to improve the quality
of the Russian capital’s drinking water supply
• 250 000 m3/d treatment capacity
• Among the most ambitious European projects in water
technology
• The first in the Russian Federation to use ultrafiltration
South-West Waterworks
Moscow South-West waterworks
•
•
•
•
•
Raw water from Moskva river
Multi-barrier concept
Treatment in 4 lines
ca. 2 h average treatment time
UF: 0.01 µm pore size
Sampling points; May 2013 (n=2)
Ultrafiltration at SWWW
NOM characterisation
• Size exclusion chromatography
 DOC quantification and fractionation using liquid
chromatography with organic carbon detection (LC-OCD)
• UV-Spectroscopy
 UVA254 and SUVA =
UVA254
DOC
• Chemical oxygen demand
 In Russia substitutes TOC or DOC monitoring
NOM characterisation
Liquid chromatography with organic carbon detection
Building Blocks (BB)
Humics (HS)
Acids and
LMW Humics
Biopolymers (BP)
LMW-Neutrals
Inorganic
Colloids
Nitrate
BP
HS
BB
LMW acids
LMW neutrals
>> 10 kDa
400-1000 Da
300-500 Da
< 350 Da
< 350 Da
Polysaccharides
Proteins
Humic and
fulvic acids
Hydrolysates of
humic substances
Carboxylic acids,
Aldehydes
Peptides,
Amphiphylic subs.
Huber et al.
(2011)
Determination of THM formation potential
• Batch determination of THMFP in real samples taken
across the waterworks
• Chlorination and chloramination using chlorine and
pre-formed chloramine solutions
• THM measurement using Gas-chromatography
NOM in raw water
•
COD = 6.2 mg O2/L
•
DOC = 6.4 mg/L
•
SUVA = 3.3 L/(mg·m)
•
NOM of terrestrial
(pedogenic) origin
Hydrophobic OC
HOC
•
High biopolymer content
Biopolymers
BP
•
Good predicted NOM
removability due to high
humics content (60%)
DOC composition
12 %
9%
4%
Humics
HS
16 %
Building blocks
BB
59 %
LMWAacids
LMW
LMWNneutrals
LMW
Moskva river. Source: lopm.ru
NOM removal across the treatment train
Oxidierbarkeit
COD
SAK254
UVA
254
7
35
6
30
5
25
30 %
16 %
4
20
36 %
3
2
15
22 %
10
21 %
5
49 %
1
30 %
0
0
Raw
Post-ozon.
Pre-ozon./
ML-filtration
Coag./Sedim.
UF
UVA (1/m)
DOC (mg/L)
COD (mg O2/L)
DOC
NOM removal across the treatment train
BP
HS
BB
LMW N
SUVA
7
4
6
3
5
2
4
1
3
0
2
-1
1
-2
0
-3
Raw
Post-ozon.
Pre-ozon./
Coag./Sedim.
ML-filtration
UF
SUVA (L/(mg·m))
DOC (mg/L)
DOC
Total NOM removal
BP
HS
BB
LMW N
4
3
SUVA
2
55 %
45.%
1,5
51 %
2
1
1
77 %
0
38 %
24 %
Total DOC removal
(cumulated)
0,5
0
removed SUVA (L/(mg·m))
removed DOC (mg/L)
DOC
 Total removal:
60 % COD
45 % DOC
55 % SUVA
 Finished water:
COD = 2.5 mg O2/L
DOC
= 3.5 mg/L
SUVA = 1.5 L/(mg·m)
Reduction of THM formation potential
Chloramination
spez.
THMFP (Chloramin)
60
6
50
5
40
4
42 %
14 %
30
6%
3
20
2
10
1
0
0
Raw
Post-ozon.
Pre-ozon./
Coag./Sedim.
ML-filtration
specific chloramine-THMFP
(µg TTHM/mg DOC)
specific chlorine-THMFP
(µg TTHM/mg DOC)
Chlorination
spez. THMFP (Chlor)
UF
pre-ozonation/coag./sedimentation > ML-filtration > UF
(removal of high MW DOC and chlorine-reactive, non-settleable particulate NOM)
THM formation potential after chlorination
Humic substances DOC (mg/L)
0
2
4
6
8
10
Chlorine-THMFP (µg THM/L)
350
300
R² = 0,83
250
UVA254
200
R² = 0,91
150
Humic
substances
100
50
0
0
2
4
6
8
10 12 14 16 18 20
UVA254 (1/m)
for DOC-fractions:
HS (0.83) > BP (0.4) > LMW N (0.35) > BB (0.1)
Conclusions
• ½ of DOC and ¾ of chlorine-activated THMFP were removed 
good agreement with other (conventional) waterworks
• Pre-ozonation/coagulation/sedimentation (+ ML-filtration) 
essential pre-treatment  reduction of UF fouling and THMFP
reduction
• DOC removal: Biopolymers > Humics > LMW neutrals > B. blocks
• Ultrafiltration removed Biopolymers completely
• UVA254 and LC-OCD-characterisation can be used for THMFP
prediction
Thank you
for your attention

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