International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 04, April 2019, pp. 671-678. Article ID: IJMET_10_04_065
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=4
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
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TESTING COMBINED APPLICATION OF
ULTRAVIOLET AND ULTRASONIC
DISINFECTION OF WASTEWATER
Nikolay Lebedev
Alexandra-Plus, Vologda, Russian Federation
Vladimir Grachev
Scientific Research Institute for Environmental Issues, Moscow, Russian Federation
Global Ecology Center, Faculty of Global Studies, Lomonosov Moscow State University,
Moscow, Russian Federation
Olga Pliamina
Scientific Research Institute for Environmental Issues, Moscow, Russian Federation
Oleg Lebedev, Dina Lukichyova
OOO Novotech-ECO, Vologda, Russian Federation
Valeriy Doilnitsyn, Andrey Akatov
Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation
Leonid Leonov
SUE “Vodokanal of St. Petersburg”, St. Petersburg, Russian Federation
ABSTRACT
This article discusses testing results of industrial trial of new wastewater
disinfection comprised of combined use of ultrasonic and ultraviolet methods at final
stage of wastewater treatment aimed at elimination of pathogenic organisms, thereby
preventing spread of infectious diseases. The new method has been developed, patented
and tested at one of the leading water service companies: SUE “Vodokanal of St.
Petersburg”. The integrated assembly was fabricated at Novotech-ECO and installed
at South-West Wastewater Treatment Plant (SWWTP, SUE “Vodokanal of St.
Petersburg”). The test results demonstrated efficiency of combined ultraviolet and
ultrasonic treatment of wastewater both in terms of disinfection improvement and in
terms of the assembly operation stability through prevention of biological films
deposition on lamp sleeves. The latter fact served as background of the challenging
project on improvement of existing system of ultraviolet disinfection at SWWTP.
http://www.iaeme.com/IJMET/index.asp
671
editor@iaeme.com
Nikolay Lebedev, Vladimir Grachev, Olga Pliamina, Oleg Lebedev, Dina Lukichyova, Valeriy
Doilnitsyn, Andrey Akatov and Leonid Leonov
Key words: Combined disinfection methods, pathogenic microorganisms, ultrasonic
and ultraviolet disinfection, wastewater, water treatment.
Cite this Article Nikolay Lebedev, Vladimir Grachev, Olga Pliamina, Oleg Lebedev,
Dina Lukichyova, Valeriy Doilnitsyn, Andrey Akatov and Leonid Leonov, Testing
Combined Application of Ultraviolet and Ultrasonic Disinfection of Wastewater,
International Journal of Mechanical Engineering and Technology, 10(4), 2019, pp. 671678.
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=4
1. INTRODUCTION
Municipal wastewater usually contains significant amount of pathogenic microorganisms,
including infectious agents. Their elimination prior to discharge is an important final treatment
stage preventing propagation of infectious diseases.
This issue is solved by means of chlorination and ozonation, wastewater ultraviolet (UV)
treatment which doesn’t generate toxic substance and which disinfection efficiency is higher in
comparison with treatment by chemical agents. Sometimes exposure to UV radiation is
combined with addition of reagents [1]. Mercury-vapor lamps are widely applied in practice
[2].
It should be mentioned that the UV disinfection efficiency decreases in case of high color
index and turbidity of medium typical of wastewater. In addition, it is noted that in the last 1520 years resistance of pathogenic microflora against ultraviolet increased four-fold [3]. One
more negative factor decreasing efficiency of this procedure is salt deposition and biological
fouling of sleeves of UV lamps [4]. As a consequence, the sleeve surfaces should be regularly
cleaned.
After development of powerful ultrasonic radiators the researchers began to consider the
possibility of their stand-alone application for disinfection treatment. Specified effects
occurring under the action of ultrasound in liquid mediums, namely: high-speed micro-streams
> 1 km/s, intensive impact waves > 1 GPa, local heating areas > 1000 K, free radicals resulting
from cavitation bubble collapse, can obviously promote destruction of pathogenic flora [5].
However, it was experimentally demonstrated that upon short impact time or low radiating
power the amount of microorganisms in some cases can even increase [6,7]. Thus, ultrasonic
treatment is applied only in combination with chemical reagents or, for instance, with UV water
treatment [2].
Combined ultrasonic and UV water treatment was proposed by Lebedev and coauthors in
2016, it is considered the most promising disinfection procedure due to combination of positive
features of both approaches [8]. It is confirmed that this combination provides synergetic
increase in disinfection efficiency due to the following effects of ultrasonic treatment:
1) crushing of suspended particles inside which microorganisms can exist [9], as well as
crushing of microorganism clusters [10] and destruction of their cell structure [11,12] with
subsequent availability and respectively increased sensitivity of microorganisms to ultraviolet
(from this point of view ultrasonic treatment should precede UV radiation);
2) intensive water agitation promoting transport of distant layers to the lamp sleeves, thus
providing uniform treatment of feed water;
3) prevention of biological fouling or salt deposition on lamp sleeves [3,13], thus providing
retention of initial intensity of lamp radiation during overall lifetime.
As a consequence of combined application of UV and ultrasonic treatment not only
disinfection efficiency increases, but lamp lifetime also increases, frequent pauses for sleeve
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Testing Combined Application of Ultraviolet and Ultrasonic Disinfection of Wastewater
cleaning are eliminated [13], the application of acid solutions aimed at cleaning and etching of
quartz sleeves is not required, which decreases maintenance costs and promotes environmental
safety. In some studies it is stated that the combined wastewater disinfection is more cost
efficient [2,3,6,13].
In recent years the combined procedure has been tested several times proving its high
efficiency [2,3,13-16]. Moreover, Novotech-ECO (Vologda, Russia) and SVAROG (Moscow)
manufacture assemblies for combined UV and ultrasonic water disinfection. The technology
developed by Novotech-ECO on the basis of piezoceramic radiators is the most promising at
present. The number of assemblies delivered from 2006 on the basis of this method is more
than three hundred. Such assemblies are successfully applied both in Russia and in neighboring
countries.
2. MATERIALS AND METHODS
The UOV-SV-5 assembly (Figure 1), designed and manufactured by Novotech-ECO (Russian
Federation), applies the aforementioned approach. It is comprised of pre-cavitator connected
with disinfection chamber and provides wastewater treatment at the flow rate up to 5 m3/h.
Figure 1 UOV-SV-5 assembly at testing site
The UOV-SV-5 was tested at SWWTP (SUE “Vodokanal of St. Petersburg”, Russian
Federation) from October 2015 to December 2016. The assembly was installed at the station of
UV treatment, where wastewater was supplied after preliminary mechanical and complete
biological cleaning. According to chemical analysis the content of suspended substances in this
water was in the range of 6.7-17 mg/dm3, and chemical consumption of oxygen was 24-61
mg/dm3. (It should be mentioned that after water treatment using this assembly these figures
remained nearly the same).
Water prior to UV treatment was taken from trough by pump, then conveyed through the
assembly and discharged back to the channel. Bacteriological analysis of water sampled at the
assembly input and output was performed in Water Research and Control Center (St.
Petersburg, Russian Federation). The following indicators were controlled: Coliphage, Total
coliforms, E. coli, Enterococcus, Staphylococcus.
The tests were comprised of three stages. The first stage (I) was devoted to various
disinfection variants at low flow rate of wastewater via the assembly (0.5-0.7 m3/h), herewith,
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Nikolay Lebedev, Vladimir Grachev, Olga Pliamina, Oleg Lebedev, Dina Lukichyova, Valeriy
Doilnitsyn, Andrey Akatov and Leonid Leonov
the UV lamp sleeves were clean upon sampling, without traces of salt deposition or biological
fouling. The second stage (II) was characterized by increased water flow rate (8-10 m3/h). And
finally, the third stage (III) implied study of intensity of biological fouling and salt deposition
on UV lamp sleeves during long-time operation of assembly at low wastewater flow rate (0.50.7 m3/h). The details of the stages are summarized in Table 1.
Table 1 Operation modes of UOV-SV-5 assembly at various testing stages
Mode
US
US-k
US+UV-1
US+UV-2
UV-k
Description
I
All ultrasonic radiators are active (8 units) (both in precavitator and in disinfecting chamber)
Ultrasonic radiators are active only in pre-cavitator (4 units)
UV lamps and ultrasonic radiators are active only in
disinfection chamber (4 units)
UV lamps and all ultrasonic radiators are active (8 units)
Only UV lamps are active, all ultrasonic radiators are
deactivated
Stage
II
III
+
+
+
+
+
+
+
+
+
3. RESULTS AND DICUSSION
The results of the first testing stage are summarized in Table 2, where either logarithmic
coefficients of inactivation (LCI) are shown, or complete treatment for the indicator is
indicated. The LCI is calculated as decimal logarithm of the ratio of living cells content in a
unit of wastewater volume before and after its treatment.
Table 2 Results of the first testing stage (flow rate: 0.5-0.7 m3/h)
Indicator
Coliphage
Total coliforms
E. coli
Enterococcus
Staphylococcus
Initial range
400-1000
BFU/100 cm3
32000-62000
CFU/100 cm3
29000-42000
CFU/100 cm3
15000-32000
CFU/100 cm3
45-150
CFU/100 cm3
LCI or result of operation in mode
US-k US+UV-1 US+UV-2 UV-k
US
0
0
Complete treatment
0
0
1.85
2.78
2.34
0
0.23
2.18
4.51
4.62
0
0.32
Complete treatment
1.65
0
Complete treatment
It is obvious that ultrasonic treatment alone does not provide significant disinfection. Weak
intensification of UV disinfection by ultrasound was observed, where the most significant
contribution was made by pre-cavitator, whereas ultrasonic radiators in disinfection chamber
exerted even negative effect. Probably, crushing of suspended particles and microorganism
clusters with subsequent removing of their protection against UV radiation was the dominating
mechanism. In addition, low wastewater flow rate via the assembly predetermined high
efficiency of UV disinfection and minor contribution of ultrasonic treatment.
Thus, at the second stage it was decided to reject purely ultrasonic modes (US, US-k), as
well as the mode without pre-cavitator (UV+US-1), and to increase water flow rate via the
assembly. The results are summarized in Table 3 and in Figure 2.
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Testing Combined Application of Ultraviolet and Ultrasonic Disinfection of Wastewater
Table 3 Results of the second testing stage (flow rate: 8-10 m3/h)
Indicator
Coliphage
Total coliforms
E. coli
Enterococcus
Staphylococcus
LCI or result of operation in mode
US+UV-2
UV-k
Initial range
330-1200
BFU/100 cm3
30000-83000
CFU/100 cm3
29000-49000
CFU/100 cm3
4700-25000
CFU/100 cm3
140-270
CFU/100 cm3
Complete treatment (> 3.08)
2.07
2.25
2.75
3.57
3.20
4.03
3.06
Complete treatment (>2.14)
2.09
Figure 2 Results of the second testing stage (flow rate: 8-10 m3/h)
Ultrasonic treatment of wastewater flow via the assembly obviously increases (by several
times in terms of absolute values) disinfecting effect of UV radiation actually in terms of all
considered properties, whereas ultrasound itself at the first stage did not demonstrate
disinfecting action.
At the third stage the capability of ultrasound to prevent biological fouling and salt
deposition on UV lamp sleeves was studied. The flow rate was again decreased to 0.5-0.7 m3/h,
but samples were taken after long-term continuous operation (at least one month). Thus, the
assembly operation stability was tested. The flow rate was reduced to maintain the experimental
integrity and to exclude possibility of discharge of depositions and impurities on the lamp
sleeves as a consequence of high linear flow rate. The results are summarized in Table 4 and in
Figure 3.
Table 4 Results of the third testing stage (flow rate: 0.5-0.7 m3/h)
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Nikolay Lebedev, Vladimir Grachev, Olga Pliamina, Oleg Lebedev, Dina Lukichyova, Valeriy
Doilnitsyn, Andrey Akatov and Leonid Leonov
Indicator
Coliphage
Total coliforms
E. coli
Enterococcus
Staphylococcus
LCI or result of operation in mode
US+UV-2
UV-k
Initial range
580-970
BFU/100 cm3
110000-190000
CFU/100 cm3
49000-72000
CFU/100 cm3
22000-56000
CFU/100 cm3
45-270
CFU/100 cm3
Complete treatment (>2.99)
Complete treatment (>2.76)
4.11
3.70
4.90
3.70
4.20
3.90
Complete treatment (>2.43)
Complete treatment (>1.65)
Figure 3 Results of the third testing stage (flow rate: 0.5-0.7 m3/h, long-term continuous operation in
corresponding mode)
The advantages of ultrasonic intensification were confirmed at the third testing stage: the
disinfection efficiency in terms of all considered microorganisms increased by several times (in
absolute values).
In addition, surfaces of UV lamp sleeves were visually inspected after long-time operation
in each mode, and intensity of deposits was studied by gravimetric method. The second
indicator was measured as follows: the deposits were removed from the sleeves by wiping their
surfaces using polyester rayon fabric. The wiping was performed after predetermined time of
the assembly operation in respective mode. The rate of biological fouling and salt deposition
was estimated by weight difference of air dry fabric before and after wiping of UV lamp quartz
sleeves. This difference is proportional to total weight of deposited impurities and products of
biological fouling of the assembly during operation.
Total weight of air dry deposits on three sleeves with respect to 1 m3 of conveyed
wastewater in UV+US-2 mode (operation of all three UV lamps and eight ultrasonic radiators)
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Testing Combined Application of Ultraviolet and Ultrasonic Disinfection of Wastewater
was 45 µg/m3, and in UV-k mode (operation of only three UV lamps) – 300 µg/m3. Therefore,
ultrasonic treatment made it possible to decrease the intensity of biological fouling and salt
deposition by 6.7 times.
4. CONCLUSION
The test results proved the efficiency of combined UV and ultrasonic treatment of wastewater
both in terms of improved disinfection and in terms of assembly operation stability by
prevention of deposition of biological films and salts on lamp sleeves. The latter fact initiated
advanced project of improvement of existing system of UV disinfection of waste water at
SWWTP. This implementation by the leading company would permit to recommend the
combined disinfection approach for wide scale application [17-19].
REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
Degremont, G. Water Treatment Handbook, Vol. 2, 6th edition. Newtown, UK: Intercept
Ltd, 1991.
Sokolova, N. F. Means and methods of water disinfection. Review. Medical Alphabet, 1(5),
2013, pp. 44-54.
Ulyanov. A. N. Lazur technology – a new step in water supply and sewage decontamination.
Water: Chemistry and Ecology, 3, 2009, pp. 11-15.
Sevryukov, I. and Afanaseva, E. Some aspects of the security of the population in
emergency situations with the pollution of the hydrosphere. Civil Security Technology,
10(1/35), 2013, pp. 22-25.
Osman, Н., Lim, F., Lucas, M. and Balasubramaniam, P. Development of an ultrasonic
resonator for ballast water disinfection. Physics Procedia, 87, 2016, pp. 99-104. DOI:
10.1016/j.phpro.2016.12.016.
Akhmedova, O. O., Stepanov, S. F., Soshinov, A. G. and Bakhtyarov, K. N. Efficiency
improvement of local water treatment stations by means of integrated electrophysical
procedures. Sovremennye Problemy Nauki i Obrazovaniya, 5, 2009, pp. 56-60.
Sesal, N. C. and Kekeç Ö. Effects of pulsed ultrasonic on Escherichia coli and
Staphylococcus aureus. Transactions of the Royal Society of tropical medicine and hygiene,
108(6), 2014, pp. 348-353. DOI: 10.1093/trstmh/tru052.
Lebedev, N. M., Lebedev, O. Yu., Grachev, V. A., Pankova, G. A., Rublevskaya, O. N.,
Vasiliev, A. P. and Doilnitsyn. Device for water disinfection in the stream. Patent RU
2664920 C2. Date of filing: 05.02.2016. Date of publication: 23.08.2018 Bulletin No. 24,
2017.
Cui, X. F., Talley, J. W., Liu, G. J. and Larson, S. L. Effects of primary sludge particulate
(PSP) entrapment on ultrasonic (20 kHz) disinfection of Escherichia coli. Water Research,
45(11), 2011, pp. 3300-3308. DOI: 10.1016/j.watres.2011.03.034.
Jin, X., Li, Z. F., Li, Y. L. and Xu, C. Improved wastewater ultraviolet disinfection by
ultrasonic pre-treatment. Proceedings of 2009 Beijing International environmental
technology conference, Beiging, PRC, 2009, pp. 498-505.
Zhang, S. and Wu, C. Effect of Wastewater Ultraviolet Disinfection of Power Ultrasonic
Enhancement. 3rd International Conference on Bioinformatics and Biomedical
Engineering, 1(11), 2009, pp. 4890-4895. DOI: 10.1109/ICBBE.2009.5162720.
Bolotova, Yu. V. and Karelina, K. A. Legionella bacteria in water supply system.
Pathogenic organisms control. Bulletin of Perm National Polytechnic University, 3(19),
2015, pp. 43-59.
Lebedev, N. M., Kazukov, O. V., Vasiliev, A. P. and Pronin, G. K. Combined ultrasonic
and ultraviolet water treatment facilities for disinfection of drinking water, water of pool
http://www.iaeme.com/IJMET/index.asp
677
editor@iaeme.com
Nikolay Lebedev, Vladimir Grachev, Olga Pliamina, Oleg Lebedev, Dina Lukichyova, Valeriy
Doilnitsyn, Andrey Akatov and Leonid Leonov
[14]
[15]
[16]
[17]
[18]
[19]
and wastes: experience of application. Proceedings of the 8th Interregional conference:
Geology, resources and issues of Bashkortostan, Ural and adjacent regions, Ufa, Russia,
2010, pp. 275-276.
Lyamtsov, A. K., Kuz`michev, A. V., Tikhomirov, D. A. and Lamonov, N. G. Water
treatment facility at cattle farms by ultrasonic cavitation and ultraviolet radiation. Innovatsii
v selskom khozyaistve, 3(13), 2015, pp. 90-93.
Sosnin, E. A., Leepatov, E. I., Skakun, V. S., Panarin, V. A., Tarasenko, V. F., Zhdanova,
O. S. and Goltsova, P. A. Ultraviolet radiation and ultrasonic oscillations impact on
wastewater. Sovremennie nauchnie issledovania i innovatsii, 3(59), 2016, pp. 125-131.
Torres-Palma, R. A., Gibson, J., Droppo, I. G., Seto, P. and Farnood, R. Surfactant-assisted
sono-breakage of wastewater particles for improved UV disinfection. Water, Air and Soil
Pollution, 228(3), 2017, pp. 106.
Karmazinov, F., Onishchenko, G., Grachev, V., Rakhmanin, Yu. and Nefedova, E. Drinking
water quality benchmarking. St. Petersburg: Novyi Zhurnal, 2010.
Karmazinov, F., Onishchenko, G., Grachev, V., Rakhmanin, Yu., Kirillov, V.,
Rublevskaya, O., Kirillov, D., Volkova, I., Plyamina, O., Zholdakova, Z. and Sinitsyna, O.
Channelization system benchmarking, Vol. 1. St. Petersburg: Novyi Zhurnal, 2011.
Karmazinov, F., Onishchenko, G., Grachev, V., Rakhmanin, Yu., Kirillov, V.,
Rublevskaya, O., Kirillov, D., Volkova, I., Plyamina, O., Zholdakova, Z. and Sinitsyna, O.
Channelization system benchmarking, Vol. 2. St. Petersburg: Novyi Zhurnal, 2012.
http://www.iaeme.com/IJMET/index.asp
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