Formation of the haloacetic acids during ozonation and chlorination of water in warsaw waterworks (Poland)

Article abstract of DOI:10.1016/S0043-1354(99)00030-5

The results of the study of the HAAs formation in Water Works in Warsaw, Poland are presented. Water taken from Zegrzynskie Lake is characterized by elevated content of humic substances and algae bloom in hot seasons. The water is ozonated and chlorinated

Full text of DOI:10.1016/S0043-1354(99)00030-5

Wat. Res. Vol. 33, No. 14, pp. 3111±3118, 1999
# 1999 Elsevier Science Ltd. All rights reserved
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FORMATION OF THE HALOACETIC ACIDS DURING
OZONATION AND CHLORINATION OF WATER IN
WARSAW WATERWORKS (POLAND)
JAN DOJLIDO1*, EDWARD ZBIEC1 and RYSZARD SWIETLIK2{
1Institute of Meteorology and Water Management, Podlesna 61, Warsaw, Poland; 2Technical
University of Radom, Chrobrego 27, 26-600 Radom, Poland
(First received November 1997; accepted in revised form January 1998)
AbstractÐThe results of the study of the HAAs formation in Water Works in Warsaw, Poland are pre-
sented. Water taken from Zegrzynskie Lake is characterized by elevated content of humic substances
and algae bloom in hot seasons. The water is ozonated and chlorinated. The study was performed from
October 1995 to November 1996. The water was analyzed on various stages of treatment and the fol-
lowing parameters were determined: HAAs, THMs, DOC, COD, humic substances, UV absorbance,
color and temperature. The big increase of HAAs concentrations occurred after water chlorination, up
to 120 mg/l. In 44% it was DCAA and in 40% TCAA. The highest concentration of HAAs was noticed
in May and June, when water temperature was the highest and concentration of organic matter the big-
gest. The changes of HAAs concentrations with time were similar to those in THMs concentrations.
The laboratory experiments on the water ozonation and chlorination indicated that ozonation has
small in¯uence on the HAAs formation.
The study of the HAAs volatization during water boiling showed that removal of HAAs is rather
small. # 1999 Elsevier Science Ltd. All rights reserved
Key wordsÐhaloacetic acids, water ozonation and chlorination
INTRODUCTION
(Pourmoghaddas and Stevens, 1995), but there are
many other factors such as organic matter compo-
Haloacetic acids (HAAs) are formed during the
sition and manner of water treatment, especially the
chlorination of organic matter occurring in water
use of other disinfectants, i.e. ozone.
taken for the treatment. In general, natural organic
Ozonation modi®es the structure of organic sub-
matter such as humic and fulvic substances are im-
stances there by in¯uencing the DBPs formation
portant precursors of HAAs.
(Calvosa et al., 1991; Yao and Haag, 1997).
It is generally known that disinfection by-pro-
Although many studies on the DBPs formation,
ducts are formed by-using chlorine as a water disin-
have been carried out the reduction of the disinfec-
fectant. The primary group of DBPs formed during
tion by-products concentration in tap water is still
the chlorination are the trihalomethanes (THMs).
an important issue (Nieminski et al., 1993).
The main representative of this group Ð chloro-
Peters et al. (1991) determined the concentration
form is recognized as a potential human carcinogen.
of HAA in drinking waters in the Netherlands. He
The second most prevalent group of chlorination
found it ranging from trace to 15 mg/l.
by-products are the haloacetic acids. Some of them,
namely dichloroacetic acid and trichloroacetic acids
Technology of water treatment
are potentially animal carcinogens (Clark, 1989).
Very large health risk has also bromodichloro-
methane (BDCM) (Rannung and Ramel, 1997).
Many studies were carried out on disinfection by-
products (DBPs) formation (Summers et al., 1993;
Fielding et al., 1987).
Water is taken from Zegrzynskie Lake. After
ozonation, coagulation, pulsators, rapid ®lter and
chlorination water is stored in reservoir in
Wieliszew (retention time 2 h). Then water is trans-
ported (ca. 5 h) to another reservoir in Bialoleka, is
chlorinated again and pumped in to the water net-
work. The scheme of water treatment and the
points of water sample intake are shown on Fig. 1.
Water ozonation was done before the coagulation
with the doses 2.4±4.3 g/m3 O3 (Fig. 4). The contact
time was 30±40 min.
It is generally known that formation of DBPs
highly depends on the organic matter content
*Author to whom all correspondence should be addressed.
[Fax: +48-22-8354926].
{Tel.: +48-361-7513; fax: +48-361-7535.
3111

3112
Jan Dojlido et al.
Study area
Water supply for Warsaw (population above
1.5 million) is taken from two sources: Vistula
River and Zegrzynskie Lake. Zegrzynskie Lake is
the impoundment on Narew River, at the point of
Bug River in¯ows. The Narew River is draining the
Mazury Lake Country, so that the water of
Zegrzynskie Lake contains humic substances.
Besides that the lake is eutrophic and in hot periods
algae blooms occur.
The water from Zegrzynskie Lake is taken for
drinking water supply of Warsaw. By water chlori-
nation the disinfection by-products are formed.
High concentrations of THMs that occurred
some years ago were lowered by the introduction of
water ozonation. But THMs problems still exist
and haloacetic acids (HAAs) were also noticed.
This study was carried out to determine main fac-
tors in¯uencing the formation of HAAs in the
Warsaw Water Works. The water samples were
taken from Zegrzynskie Lake (raw water), on the
various stages of water treatment and tap water
(Fig. 1).
MATERIALS AND METHODS
Method of analysis
A method was developed for the simultaneous analysis
of 5 HAAs:
. monochloroacetic acid (MCAA),
. monobromoacetic acid (MBAA),
. dichloroacetic acid (DCAA),
. trichloroacetic acid (TCAA),
. dibromoacetic acid (DBAA).
The haloacetic acids were extracted from water sample
with methyl tertiary butyl ether (MTBE). To increase the
extraction eciency
a salting agent was added. The
extracted compounds were esteri®ed with diazomethane
solution to produce methyl ester derivatives. The obtained
methyl derivatives were determined using gas chromatog-
raphy with electron capture detector (ECD).
The detection limit of the method, according to the
Standard Methods of APHA et al. (1995) is 0.05±0.08 mg/l
depending on the compound. The method was checked for
the recovery of HAAs. It was found that the relative stan-
dard deviation for the samples with added known amount
of HAAs was from 3.9 to 5.9% for river water and mean
recovery was 81.3±104.0% depending on the compound.
Fig. 1. Technology of treatment. Dotted squares resemble
the sampling points.
Water was chlorinated twice, before storage reser-
voirs (Fig. 1). The average monthly doses of chlor-
ine were changing from 2.1 to 3.7 g/m3 Cl (Fig. 4).
After the last storage reservoir the free chlorine
residual was between 0±0.6 g/m3 and combined
chlorine residual was changing between 0.6 to 1.5 g/
m3.
RESULTS
HAAs in water of Warsaw Waterworks
The study was performed in the period from
October 1995 to November 1996. The analysis were
done every month. Haloacetic acids were deter-
mined and other parameters connected with disin-
fection by-products such as: humic substances,
organic carbon, COD, absorbance UV, color, tem-
perature, chlorine and ozone dosis and THMs.
The haloacetic acids in raw water (from
Zegrzynskie Lake) were found in trace concen-
trations; very often there were below detection
limit.
Water ozonation gave a very small increase of
HAAs, maximum 1 mg/l but often no increase was
observed.

Formation of haloacetic acids
3113
Fig. 2. Changes of HAAs concentration after di€erent steps of treatment (average value).
Fig. 3. Change of total HAAs in time in the tap water (sampling point No. 6).

3114
Jan Dojlido et al.
Fig. 4. Changes of total HAAs in treated water (sampling point No. 5) in comparison to TOC, water temperature, doses
of chlorine and ozone.
A big increase of HAAs was noticed after the HAAs was lower, (20±50 mg/l). The changes of the
®rst chlorination. The second chlorination gave a
further increase (Table 1).
concentration of the individual haloacetic acids
were varying with time but in general were the
same as for the sum of HAAs.
In tap water, concentration of HAAs increased
for MCAA, MBAA and DBAA but decreased for
DCAA.
The changes in HAAs concentration were com-
pared with variations of other water parameters
and with the chlorination practice. The highest
doses of chlorine were used in April and May and
June, when the algae concentrations in water of
Zegrzynskie Lake were the highest. In May and
June the contents of HAAs were the highest. It was
also noticed that more HAAs was produced at high
TOC values but the relationship was irregular.
A very clear relationship was established between
the concentration of HAAs and the humic sub-
stance content (Fig. 5) and UV absorbance.
The sum of HAAs in tap water was lower than
that after the last chlorination (Fig. 2).
Evaluating the content of produced HAAs the
®ndings were as follows:
DCAA±44%, TCAA±40%, MCAA±12%,
MBAA±2%, DBAA±2%, of the 100- 5 HAAs:
The concentrations of HAAs were changing with
time and depended on the season (Fig. 3). The low-
est concentrations were found in winter, namely in
January, February and March. The sum of HAAs
was below 13 mg/l. The highest concentrations
occurred in May and June and reached 120 mg/l. In
early spring and autumn the concentration of
In general, more haloacetic acids were produced
at higher concentration of organic matter (precur-
sors). In May and June, when the highest concen-
tration of HAAs were observed, the content of the
organic matter in raw water was highest also.
A big in¯uence of water temperature on the pro-
duction of haloacetic acids was observed (Fig. 6).
At low water temperature (in January, February
and March) a small amount of HAAs was pro-
duced; at temperatures, above 208C (in May and
June) the highest concentrations of HAAs were
observed.
Table 1. Average concentration of HAAs after chlorination (mg/l)
First chlorination
Second chlorination
MCAA
DCAA
TCAA
MBAA
DBAA
1.76
13.34
8.18
0.12
0.36
3.57
25.55
15.20
0.42
We may conclude, that the reaction of HAAs for-
mation is highly dependent on temperature and is
faster at high temperature.
0.45

Formation of haloacetic acids
3115
Fig. 5. Changes of HAAs concentration in relation to humic substances content.
The changes of HAAs concentrations were com- Water chlorination and ozonization in laboratory
conditions
pared with used doses of chlorine. In the period of
high content of HAAs, the bigger doses of chlorine
were used.
To study the haloacetic acids formation the ex-
periment of chlorination and ozonization exper-
iments were performed. Water from Zegrzynskie
Lake was ozonated during 15, 60, 120, 240 and
360 min. Then water was chlorinated through 24 h
and HAAs were determined. Ozone dose was 0.4±
The relationship between produced HAAs and
produced THMs was analyzed (Fig. 7). The changes
in concentration of THMs and HAAs were very
similar.
Fig. 6. Relation of the HAAs concentration on temperature.

3116
Jan Dojlido et al.
Table 2. The concentration of HAAs after ozonation and chlorination in laboratory conditions
Ozonation time (min)
Chlorination of ozonated water after the time in min
0
15
60
120
240
360
0
15
60
120
240
360
MCAA, mg/l
MBAA, mg/l
DCAA, mg/l
TCAA, mg/l
DBAA, mg/l
Sum HAAs, mg/l
n.d.
n.d.
0.14
0.06
n.d.
0.20
2.83
n.d.
0.35
0.15
0.07
3.40
4.92
0.04
0.46
0.26
0.07
5.75
13.40
0.04
0.58
0.29
0.07
14.38
14.76
0.11
0.56
0.37
0.29
16.09
27.05
0.24
0.49
0.59
0.51
28.88
1.73
0.08
54.83
0.97
n.d.
2.67
0.34
54.46
4.10
n.d.
8.28
0.48
57.06
3.57
n.d.
11.43
0.24
58.98
2.39
0.21
38.12
0.22
39.92
1.23
0.21
54.73
0.06
39.44
1.23
0.21
57.61
61.57
69.39
73.25
79.70
95.67
10.3 mg/l O3, chlorine dose 3±5 mg/l Cl2 and chlor-
Summarizing we can state, that after ozonation
ine residual r0.5 mg/l Cl2. The results are shown in only MCAA was found at signi®cant content, other
Table 2.
MCAA. During ozonation the chloroacetic acid
acids were at trace level.
Theoretically the adding of ozone can not be the
was produced, up to 27 mg/l after 360 min. The reason for chloroacetic acid formation. It could be
chlorination of ozonated water sharply increased explained by the oxidation process of chloride to
the content of HAA. After 360 min the process of hypochlorite ion (Grguric et al., 1994) by the high
formation was not ®nished.
dose and long contact time of ozone. The reaction
DCAA. After ozonation only trace concentrations may occur
of HAAs were found. The chlorination produces
high content of the acid, up to 54 mg/l. It was
noticed that with longer ozonation time, the
amount of produced DCAA was decreasing.
TCAA. The ozonation gave only trace amount of
acid. The chlorination produces small content of
the acid, up to 4 mg/l. The longer ozonation time,
the lower concentration of produced TCAA was
noticed.
O3 ‡ Cl 4O2 ‡ OCl
The chlorination produced high amount of
MCAA and DCAA, other acids were at low con-
centrations. The time of ozonation in¯uenced the
content of acid produced in chlorination process,
positively for MCAA and negatively for DCAA.
Volatilization of HAAs during water boiling
MBAA. The ozonation produced only trace
amount of the acid, the chlorination also very small
content. With longer ozonation time the produced
MBAA content was lower.
DBAA. The ozonation and the chlorination pro-
duced only trace amount of that acid.
The haloacetic acids have the boiling tempera-
tures of about 2008C. It is well known that other
disinfection by-products such as the trihalo-
methanes could be removed from drinking water by
boiling what can improve the water quality.
Fig. 7. Content of THMs and HAAs in treated water.

Formation of haloacetic acids
Table 3. Changes of the HAAs during water boiling
Decrease of the acid (%)
3117
the content of HAAs and such parameters as COD,
DOC, humic substances concentration and UV
absorbance was noticed. The conclusion can be
drawn that the HAAs formation was dependent on
organic matter concentration (precursors).
HAA
MCAA
MBAA
DCAA
TCAA
DBAA
5±8
26±31
17±19
69±72
9±13
But the much better correlation between the
HAAs content and water temperature was found.
There is the conclusion that the formation of HAAs
depends greatly on water temperature.
The relationship between the HAAs content and
doses of chlorine was also noticed.
A very close relationship between the content of
HAAs and THMs was observed. The conclusion is
that there was the same reason for HAAs and
THMs formation.
The water ozonation and chlorination in labora-
tory conditions showed that the sum of HAAs was
at the same level as that in the study of Warsaw
Waterworks, but the proportion of individual HAA
was di€erent which can be caused by di€erent con-
ditions. It was found that time of ozonation can in-
¯uence the formation of HAAs, some HAAs
increase and other decreases with the longer time of
ozonation. But the periods of ozonation in labora-
tory experiment were very long (up to 360 min),
practically never used in water works.
The possibility of removal the HAAs during
water boiling was tested. A known amount of the
HAAs was added to drinking water in Warsaw.
Part of the water was stored for 24 h at a tempera-
ture ca. 68C, the other part was boiled for 10 min;
then the HAAs were determined. The concentration
of HAA in cold water did not change. The losses of
HAAs during boiling are presented in Table 3.
. the losses of MCAA were small (5±8%),
. the concentration of DBAA changed very little
(9±13%),
. there was some removal of DCAA (17±19%),
. there was some loss of MBAA (26±31%),
. but the biggest losses were in case of TCAA (69±
72%).
The experiments were done on the removal of
HAAs during water boiling like in the consumer's
kitchen. The losses of four HAAs were rather
small. The bigger removal of TCAA could be
attributed to the decomposition of TCAA into
chloroform.
It can be explained by decomposition of TCAA
in boiling.
CCl3COOH boi4ling CHCl3 ‡ CO2
There is the conclusion that water boiling does
not easily removed the HAAs while it does is in
case of THMs.
The volatile chloroform is produced, that belongs
to the THMs group.
DISCUSSION
CONCLUSIONS
The concentration of haloacetic acids in water of
Water ozonation has small in¯uence on the
Zegrzynskie Lake was at the trace levels or below HAAs formation. The haloacetic acids are pro-
limits of detection. During the water ozonation very duced during water chlorination. The content of
small amount of HAAs was produced.
HAAs depended mostly on the water temperature
The haloacetic acids were formed in the chlori- and to a smaller extent on the concentration of or-
nation process. Mostly there were chlorinated com- ganic matter. The water boiling does not remove
pounds; at very low levels the brominated the HAAs while it does in case of THMs.
derivatives were produced.
Among the 5 HAAs the highest concentrations
were found for DCAA and TCAA.
The concentrations of HAAs were changing with
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