Journal of Minerals & Materials Characterization & Engineering, Vol. 11, No.5, pp.479-492, 2012
jmmce.org Printed in the USA. All rights reserved
479
Corrosion of Water Pipes: a Comprehensive
Study of Deposits
Vikas Chawlaa, Prema G. Gurbuxanib*and G.R. Bhagurec
aDepartment of Mechanical Engineering, B.M.S.C.E Muktsar-152026, Punjab, India
bChemistry Department, Smt. C. H. M. College, Ulhasnagar-421003, India
cChemistry Department, Dnyanasadhana College, Thane-400604, India.
*Corresponding author: gurprema@gmail.com
ABSTRACTS
Corrosion scales play an important role in modifying water quality in drinking water
distribution systems. The corrosion scales from old water pipe lines were analyzed for their
structure and composition. This paper presents the results of comprehensive study of deposits
found in water distribution system of Ulhasnagar city of Maharashtra, India. Scales were
investigated by XRD, FTIR, SEM and ED’s analytical techniques. It was found that goethite,
magnetite, lepidocrocite, hematite and Akaganite were identified as the primary constituents of
brown deposits. The corrosion scales had a shell-like, enveloping layer, covering porous
deposits of iron oxide phases. Our studies were able to identify important constituents of three
different pipes of water distribution systems. Akaganite was found to be present in chloride
environment. Along with iron hydroxide phases it was found that corrosion product also contain
some organic matter which may be due to adsorption of biofilm on the surface of pipe. Further
studies are needed to establish the role of corrosion scales in the mechanism of iron release from
corroded pipes.
Key words: corrosion, water distribution system, brown deposits, iron oxides, bio-film.
1. INTRODUCTION
480 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
The water distribution system is key public health battlefield of the 21st century. Iron and steel
pipes have been used in water distribution systems for over five centuries. The water distribution
network cannot be considered as inert system but a reactor interacting with the interior aqueous
environments. During interaction the formation of unwanted deposits takes place [1]. The main
source of deposit are particulate matter transported by water, dissolved oxygen, microbial
activity, chlorides, sulphates and physicochemical reactions both at the pipe wall interface and
within the water bulk [1-5]. Most water distribution systems have build up of iron corrosion
products inside the iron pipes. Corrosion scale /deposits not only restrict the flow of water [6] but
also degrade the quality of water. The scales are porous deposits that are comprised of iron
hydroxide phases. Some wa ys in which corrosion scales can advers el y affect the w ater qu ali ty in
drinking water distribution pipes are 1) As a source of iron which then released into water can
result in red water or which may change colour, odour and taste, 2) as source of high demand for
dissolved oxygen and chlorine, 3) as an excellent breeding ground for microbes and, 4)
adsorption and accumulation of substances such as arsenic [9-12] which when released on
modification of water quality. Ionic species coming either from natural source or from pipe
scales h ave been found to be p robable cause o f publ ic health problems [ 13]. Additionall y deposit
formation may drastically reduce the hydraulic capacity of pipelines due to formation of
tubercles [14].
Many research workers recently studied the composition of deposits in potable water system
indicates that minerals, organic matter and biomass are the main constituents of drinking water
deposits. Morphology and composition of corrosion products formed on the internal walls of
ferrous pipe lines have also been studied revealing a strong influence of water quality on the
characterization of deposit material and a direct correlation between composition of deposits and
the bacterial species found [2]. Extensive public survey in the Ulhasnagar city of Maharashtra,
Ind ia, reveals that lack of water through pipe, odour and colour of the water are not in the
permissible limit. Therefore comprehensive study has been carried out to understand the
consequences. Three pipe samples which forms a part of water distribution s ystem in the city has
been considered as sample for the study.
These Pipe samples were studied to characterize the physical properties and chemical
compositions of corrosion scales using several analytical techniques such as XRD, FTIR, SEM
and EDS. Both organic and inorganic matter was found to make part of the deposit. The
compounds forming the deposits are reported.
2. MATERIAL AND METHODS
The infrastructure studied forms a part of Ulhasnagar Municipal Corporation. The pipe line was
installed in the year 1952 to carry drinking water from Water treatment plants to Distribution
storage tank. These pipe samples were labeled as big pipe, medium pipe and small pipes
Vol.11, No.5 Corrosion of Water Pipes: a Comprehensive Study 481
according to their size. These pipes were made from cast iron and the elemental chemical
composition of pipes lines provided by Municipal Water supply department is presented in the
Table-1. Corrosion products were removed from the inner surface of pipes by 600 grit paper and
dried for 48 hours at 40 0C. Then corrosion products were grinded using an agitate Mortar until
approximately 98% passed a no.325 mesh. Tools and techniques were XRD, FTIR and SEM and
EDS.
Table-1: Elemental Chemical Composition (%age) of Pipe Sample
Element Fe
Mn
Si
S
C
Mg
P
% of
Element 94 0.10-0.90 2.00-3.00 0.03
Max. 3.00-4.00 0.030-0.080 0.10 Max.
3. RESULTS AND DISCUSSION
3.1. Big Pipe Sample
The EDS measurement on powder sample ( brown deposit) from the big pipe identified that iron
was the major component element of the scales besides carbon and oxygen.EDS anal ysis showed
that iron was present 30.29% (ato mic per cent), C arbon at 8.86%, ox ygen at 59.99%, while trace
amount of other element such as Aluminium, Silicon, and Chlorine (See Table-2). The corrosion
products are analysed by XRD and the results are shown in Fig.1.Goethite, α-FeOOH,
Fe2O3.H2O (Hydrated ferric oxide), hemitite α- Fe2O3. Magnetite, Fe3O4 and lepidocr cocit e, Y-
FeOOH, FeO3.H2O ( hydrated ferric oxide).
Table-2: Most typical Values of brown deposits of Big Pipe Sample Obtained from EDS
Analysis.
Element
C
O
Al
Si
Cl
Fe
Zr
Total
Weight %
3.76
34.11
0.15
0.29
1.16
60.52
--
100
Atomic % 8.86 59.59
0.16
0.28 0.92 30.29 -- 100
482 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
Fig.1: SEM Morphology of Big Pipe
It is confirmed from XRD Spectrum of big pipe sample (Fig.2) that the corrosion product mainly
consist of Geothite; further result of XRD analysis shows that brown deposits reveal important
variations according to colour intensity ;dark deposits appear to be amorphous and the lighter
brown deposit contain crystalline compounds.Quartz as the main constituent mixed with an
aluminium silicate hydroxide,most probably Kaoline.Similar compounds in potable water system
were reported by many research workers[16,25].The SEM mophology of big pipe sample (Fig.1)
shows that goethite was stallactite –like on the surface of iron pipe .The grain of goethite was
tiny and needle shape since it formed in the intial corrosion stages on the iron surface.The
tubercle deposits formed in water system showed mainly the presence of Goethite and Magnetite
with minor amount of Lepidocrocite (Fig.2).
Vol.11, No.5 Corrosion of Water Pipes: a Comprehensive Study 483
Fig.2.XRD Spectrum of Corrosion Product of Big Pipe Sample.
Fig.3: FTIR Spectrum of Big Pipe
Figure-3 shows the FTIR Spectrum of the Big pipe with a peak at 3380cm-1 indicati ng presen ce
of aluminosilicat e ,Vibration of amide species at 1653 cm-1 indi cating the presence of biological
material in the sample ,similar obseravation was also reported by L.I.Sily and et.al. [26] and
V.Guatheier and et.al. [27]. Another peak at 3147 cm-1 indicates the presence of aromatic
group,Complex silicate [19] containing water or hydroxide groups seen at 1129 cm-1 and at 547
cm-1. Peaks at 1020 cm-1 and at 887 cm-1 indicates the prescence of Lepidocrocite and
484 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
goethite [19]. Peak at 797 cm-1 indicates the presence of C-C vibrations and C-Cl vibrations.
Similarly peak at 547 cm-1indicates the presence of methyl group attached to silicon in silicate
(Table-3).
Table-3: Result of the analysis of the IR Spectra of Big pipe Sample:
Sample
(Spectrum
)
Absorption
Fre quency (cm-1)
Related Compounds , Groups or
Vibration
Referen ces
Big Pipe
3380
Aluminosilicate
19
3147
C-H aromatic
19
1653
C=C , Vibration of amide Species
19
1129, 547
Complex Silicate containing Water or
Hydroxide group Vibration. 19
1020
Lepido crocite
19
887
Goethite
19
797
C-C Vibration, and C-Cl
20
547
Presence of methyl group attached to
silicon in silicate 19
According to many research workers on the corrosion of iron water pipes and iron objects [17,
23,24] electrochemical process occures on iron in moist environment. Th e form ed ru st are i n f act
a sort of precipitation with a very fine rust grain and loose distribution. As a result the oxygen
and water are easy to approch the metal core and enhance the corrosion.
Fe ---- ---Fe+2 +2e- (1)
1/2O2+H2O +2e______ ___ 2 OH- (2)
Fe+2 + 2OH ----------Fe(OH)2 (3)
Fe(OH)2 + O2 -------Fe 2O3.H2O Or 2 FeOOH (4)
It was reported [18] that in the humid environment iron is corroded toY-FeOOH in the
beginning ,thenwith the intraction with water and oxygen Y-FeOOH.This coinsides with the
experimental results .Analysis of historic data revels that the formation of geothite and
lepidocrocite is feavoured in solutions with pH 5 to 7, whilist pH values above 8 privilege
magnetite formation [29]. In the proportion amount of Goethite and Lepidocrocite was found
higher than the magnetite. As bleaching poweder or chlorine dioxide is used in water tretment for
disinfection, in chlorine environment water favours the formation of image
Vol.11, No.5 Corrosion of Water Pipes: a Comprehensive Study 485
3.2 Medium Pipe
The EDS measurement on powder sample ( brown deposit) from the medium pipe identified
that iron was the major component element of the scales besides carbon and oxygen. EDS
analysis showed that iron was present 36.09 % (atomic percent), Carbon at 10.18 %, oxygen at
53.14 % while trace amount of other element such as Silicon and Chlorine (Table-4). The
corrosion products are analysed by XRD and the results are shown in Fig.5. Goethite, α-FeOOH,
Fe2o3.H2O (Hydrated ferric oxide), Magnetite, Fe3O4 and alkaganite,ß-FeOOH, Fe2O3.H2O (
hydrated ferric oxide). It is confirmed from XRD Spectrum of medium pipe sample (Fig.5) that
the corrosion product consist of maximum amount of Geothite, probable amount of akaganite
and least amount of maganite.
Table-4: Most typical Values of brown deposits of Medium Pipe Sample Obtained from EDS
Analysis
Element
C
O
Al
Si
Cl
Fe
Zr
Total
Weight %
4.08
28.89
--
0.55
--
66.97
---
100
Atomic % 10.18 53.14
--
0.59 -- 36.09 --- 100
It has been reported [29] that production free energy of goethite at 250C is-495.748KJmole-1 ,
which is less than that of akaganite -481.7KJ and maganetite -482..Accordingly it can say that
goethite is more stabler than maganitite and akaganite in thermodynamics. Magnetite formation
is enhanced under the low oxidation codition where as akaganite formation is enhanced in the
chloride environment [30]. From EDS data of medium pipe (Table-3), it can be seen that
chlorine percent is more in medium pipe which fevours the formation of akaganite than the
maganetite.It is reported that chloride ion trapped in the lattice of akaganeite [31]. So induced
chloride in the molecular structure of ß-FeOOH, Fe2O3.H2O ( akaganeite) is a risk for iron
material and chloride element carried by the akaganeite is the main potential trouble. It has been
also reported that ß-FeOOH [33] could act as an acc elerat i n g ag ent and pr om ot e el ectro ch em ical
corrosion process. The ß-FeOOH works as a reservoir of chloride and the rust layer becomes
porous [34].The chloride ions can move through the rust layer and arrive at metal surfaces
easily [35]. So akaganeite can be main harmful trouble in water pipes which enhance the further
corrosion which may also supply the fevourable condition for the local corrosion to great extent
[32]. The SEM mopholog y of medium pipe sam ple (Fig.4) shows that goethite was stalactite –
like on the surface of iron pipe .The grain of goethite was tiny and needle shape this was
confirmed in the earlier section (Fig.4).
486 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
Fig.4: SEM Morphology of Medium Pipe
Fig.5: XRD Spectrum of Corrosion Product of Medium Pipe Sample.
Vol.11, No.5 Corrosion of Water Pipes: a Comprehensive Study 487
Fig.6: FTIR Spectrum of Medium Pipe Sample
Figure 6 shows the FTIR Spectrum of the medium pipe with a peak at 3390cm-1 indicating
presence of envelope of hydrogen bond surface OH group. Peak at 3152 cm-1 indicates the
Vibration of OH group in goethite similar result also obtained from XRD Sectrum of medium
pipe. Vibration in water shows at 1635 cm-1. Peaks at 1115 cm-1 indicates the presence of
complex silicate containing water or hydroxide group vibration whilist peak at 1020 cm-1
indicates the presence of C-C vibrations. Peak at 887 cm-1 and 796 cm-1 vibrations due to
presence of C-C and C-Cl. Peak at 455 cm-1. Vibrations of amide species at 1650 and 1550 cm-1
have been reported [26] (Table-4) which as indication of biological material in the sample.
Howeve r ,the ex istan ce of i nor ganic m ateri al generat es interf eren ce in that re gion [26] which is
the case observed in the present study. Consequntly for cases of deposits composed by mixtures
of organic and inorganic matter a better indication of the presence of biofilm.
3.3 Small Pipe
The EDS measurement on powder sample ( brown deposit) from the small pipe identified that
iron was the major component element of the scales besides carbon and oxygen. EDS analysis
showed that iron was present 34.45 % (atomic percent), Carbon at 5.86 %, and oxygen at 59.70
%. (See Table-4). The corrosion products are analysed by XRD and the results are shown in
Fig.8. Goethite, α-FeOO H ,Fe2o3.H2O (Hydrated ferric oxide), and Iron Matrix. It is confirmed
from XRD Spectrum of small pipe sample (Fig.8) that the corrosion product consist of
maximum amount of Geothite,rest of the amount was iron matrix.The composition of grain like
substance is already confirmed in previous saction.The SEM mophology of small pipe sample
(Fig.7) shows that goethite was stalactite –like on the surface of iron pipe .The grain of goethite
488 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
was tiny and needle shape this was confirmed in the earlier section (Fig7). Lot of cavities or
gaps are seen and iron matrix is exposed on local surface.
Table-5: Result of the analysis of the IR Spectra of Medium pipe Sample
Sample
(Spectrum)
Absorption
Frequency (cm-1 )
Related Compounds , Groups or
Vibration
Referen ce
Small Pipe
3409
0H phenolic
21
3150
C-H aromatic
22
2922 & 2853
C-H aliphatic
22
1635
C=C
22
1119
C-O
22
1020
C-C & C-O
22
886 ,796
Goethite
19
Table-6: Most typical Values of brown deposits of Small Pipe Sample Obtained from EDS
Analysis.
Element
C
O
Al
Si
Cl
Fe
Zr
Total
Weight %
2.38
32.38
--
--
65.23
--
100
Atomic % 5.86 59.70
-- -- 34.45 -- 100
Vol.11, No.5 Corrosion of Water Pipes: a Comprehensive Study 489
Fig.7: SEM Morphology of Small Pipe
Fig.8: XRD Spectrum of Corrosion Product of Small Pipe Sample.
Fig.9 shows the FTIR Spectrum of the small pipe with a peak at 3409 cm-1 indicating presence
phenolic OH group. Peak at 3150 cm-1 indicates the presence of C-H vibration in CH 3 or
CH2. group. Peaks at 886 and 796 indicates the presence of goethite, similar result also
obtained from XRD Sectrum of small pipe. Vibrations due to presence of C-H aliphatic group
obsereved at 2922 cm-1 and 2833 cm-1. Another peak at 1635 cm-1.indicates the presence of C=C
vibrations. Besides the presence of C=O stretch was noticed at 1119 cm-1 and C-C alphatic
stretch seen at 1020 cm-1. Presence of organic functional group indicates the adsorption of
biofilm in water pipe [16,27]. It has been explained in the earlier section of medium pi pe that the
490 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
existance of inorganic material generates interference in that region [26] which is the case
observed in the samll pipe. Consequntly for cases of deposits composed by mixtures of organic
and inorganic matter a better indication of the presence of biofilm [16,27]
Fig.9: FTIR Spectrum of Small Pipe Sample
Table-7: Result of the analysis of the IR Spectra of Small pipe Sample
Sample
(Spectrum)
Absorption
Frequency (cm-1 )
Related Compounds ,
Groups or Vibration
Referen ce
Small Pipe
3409
0H phenolic
21
3150
C-H aromatic
22
2922 & 2853
C-H aliphatic
22
1635
C=C
22
1119
C-O
22
1020
C-C & C-O
22
886 ,796
Goethite
19
4. CONCLUSIO N
The analysis of deposit in water distribution pipes of Ulhasnagar city revels that the
predominance of brown deposits. Organic matter was also found to present. Brown deposits in
big pipe sample contain aluminosilicates compounds. Tubercles are formed by electrochemical
Vol.11, No.5 Corrosion of Water Pipes: a Comprehensive Study 491
and microbiological activity. They are composed mainly of goethite, Lepidocrocite, hematite and
magnetite. Similarly medium pipe composed of Goethite, Akaganite and magnetite while small
pipe sample composed of Goethite and iron matrix. FTIR analysis could be used as indication of
the formation of organic material in the sample and therefore, as indicator of the presence of
biofilm. An interference of spectra has been observed due to mixture of organic and inorganic
mixture in the sample.
ACKNOWLEDGEMENTS
The Authors wish to thank Ulhasnagar Municipal Corporation Authorities for providing pipe
samples and other important information and S.A.I.F. IIT Mumbai. The Authors also thankful to
Dr. Bhatt, Scientist, BTRA Mumbai and Dr. S.R.Mirgane, Associate Professor, J.E.S.College,
Jalna for their valuable suggestions and guidance.
REFERENCES
[1] Heryong Jung, Unij Kim, Gyutae Seo, Hyundong Lee and Chunsik Lee, (2009)
Environmental Engineering Research, Vol.14, No.3, 195-199.
[2] T.S. Rao, T.N. Sairam, B. Vishwanathan and K.V.K. Nair, (2000) Corrosion Science,
Vol.42, No.8, 147-131.
[3] P. Sarin, V. L. Snoeyink, J. Bebee, W. M. Kriven and J. A. Clement, (2001) Water
Research . Vol. 35, no. 12, 2961–2969.
[4] Benjamin M.M.Sontheimer H. and Leroy P.(1996) Corrosion of Iron and Steel in Internal
Corrosion of Water Distribution Systems,Cooperative Research Report,AWWA Research
Foundation,Denver Co.
[5] Lechevallier M.W.Lowry C.D.,Lee R.G. and Gibbon D.L.(1993) Journal of AWWA,85(7),
111-123.
[6] S,A, Imran, J .D. Dietz, G. Mutoti, J.S. Taylor, A.A. Randall and C.D. Cooper, (2005)
Journal AWWA, Vol.97, No.9, 93-100.
[7] Zhe Zhang Janet E.Stout Victor L. Yu, Radisav Vidic, (2008) Water R esearch ,Vol.42,129-
136.
[8] Aieta E.M. Berg D.J.A (1986) J.AWWA, Vol.78(6), 62-72.
[9] O.M. Zachus, M.J. Lehtola, L.K. Korhonen and P.J. Martikainen, (2001) Water Research,
Vol.35, No.7, 1757-1765.
[10] M.W.Lechevallier,T.W.Babcock and R.G. (1987) Applied and Environmental
Biology,Vol.53,No.12,2714-2724.
[11] Ravin K.P.Jain A. and Loeppert R.H.,(1998) Environ.Sci.Technology,32(32) 3, 344-349.
[12] ESPA Arsenic Guidelines
[13] Larson and Skold R.V. (1957) J.AWWA,Vol.49,1294-1301.
492 Vikas Chawla, Pr ema G. Gurbuxani Vol.11, No.5
[14] Viraghavan T; Subramanian K.S.Rao and Rao B.V. (1996) Journal Environmental Science
Health Association 31(8),2005-2016.
[15] Felix Excheverria ,Juan G. Castano, Carlos Arroyave, Gustrao Penuela Auxilo Ramirez and
Jordi Morato, J.A WWA (2009) Vol.17 No.2,275-281.
[16] Gauthier, J.M. Portal, Y. Yvon, C Rosin, J.C. Block, V. Lahoussine, S. Benabdallah, J.
Cavard, D. G atel and S. Fass, (2001) Water Science and Technology, Water Supply, Vol.1,
No.4, PP 89-94.
[17] Geldreich E.E. Internal Corrosion and Deposition Control in Water Quality and Treatment ,
McGraw Hill, New York,1990.
[18] Wang Zise, Xu Chunchun, CAO Xia, and Xu Ben, (2007). Chin.JournalChem.Eng;15(3),
433-438
[19] H. Komada. Technical bulletin 1985-1E”. Research Program Service, Minister of
Supply and Services, pp. 198. Ottawa, Canada.
[20] E. Contreras, E. Leal and M. I. Martínez. (2004) RevistaTécnica de la Facultad de
Ingeniería. Universidad del Zulia. Vol. 27 Nº 2,114-122.
[21] S. Music, G. P. Santana, G. Smit and V.K. Garg. (1998) Journal of Alloys and
Compounds.Vol. 278 No. 1, 291-301.
[22] A.I. J. Mendham, R.C. Denney, J.D. Barnes, and M. Thomas, (2000) Vogel’s Quantitative
Chemical Analysis,6th Edition ,720-744.
[23] Sarin, P. Snoeyink,V.L;B.L. Lytle,D.A; (2004) Journal Environmental Engineering ,
Vol.130 (4), 2004, 365-373.
[24] Tang Z,; Hong, S; Xi ao W, Taylor, J; (2003), Corrosion Science, Vol.48(2), 322-342.
[25] J.Lin and B.A.W. (1998) Water Research,Vol.32,No.4, 1019-1026.
[26] L.I. Sly, M.C. Hodgkinson and V. Arunapairojana, (1990) Applied an Environmental
Microbiology,Vol.56,No.3,628-639.
[27] V.Gauthier, B.Geanard, J.M.Portal, J.C.Block and D.Gatel, (1999) Water Research,
Vol.33, No.4, 1014-1026.
[28] S.Music,G.P.Santana,G.Smit and V.K.Garg, Fe Mossbauer, (1998) Journal of Alloys and
Compounds,Vol.278.No.1, 291-301.
[29] Zhu,H.F. Zhou,H. Cai,L.K., (2002) Conserv.Archaeol;14(Suppl.),52-62.
[30] L.A.Raman ,(2006), Water Research,Vol.No.13,2493-2502.
[31] S.T. Wang, S.W. Yang, K.W. Gao¤ and X.L. He( 2008) Acta Metall. Sin.(Engl.
Lett.)Vol.21 No.6,425-436 .
[32] T. Nishimura, H. Katayama, K. Noda and T. Kodama, (2009) Corrosion 56(9), 935.
[33] ISO-DIS 8565.2 Metal and Alloys-Atmospheric Corrosion Testing-General Requirement
for Field Test (Geneva, Switzarland: ISO,1991.
[34] T.E. Graedel and R.P. Frankenthal, J. Electrochemica. Soc. 137(8) (1990) 2385.