The 13th International Forum on Strategic Technology（IFOST 2018）
Analysis of Parasitic Contamination in Wastewater at
the Sewage Treatment Plant in the City of Yakutsk
Natalia Tonoeva1st
Novosibirsk State Technical
University, NSTU
Novosibirsk, Russia
tonoeva1395@mail.ru
Elena Efremova2nd
Institute of Experimental
Veterinary Science of Siberia and
Far East,Siberian Federal Scientific
Centre of Agro-Biotechnologies of
the Russian Academy of Sciences
Novosibirsk, Russia
alfa_parazit@mail.ru
Evgeniy Udaltsov3rd
Novosibirsk State Technical
University, NSTU
Institute of Experimental Veterinary
Science of Siberia and Far East,
Siberian Federal Scientific Centre of
Agro-Biotechnologies of the
Russian Academy of Sciences
Novosibirsk, Russia
ugodnic@gmail.com
with intensive incidence rates, such as Khakassia (103.56),
Yamalo-Nenets District (54.83), Krasnoyarsk Territory
(40.79), the Komi Republic (20.96) and Buryatia (15.78) [3].
Diphyllobothriasis is today the most widespread
biohelminth infection in the northernmost parts of Russia,
and presents a particularly potent public health issue for the
Sakha Republic (Yakutia). Local epidemiological factors for
diphyllobothriasis include anthropogenic water pollution
and the traditional consumption of insufficiently cooked fish
by the indigenous population.
Abstract--Municipal-domestic
wastewater
containing
propagative forms of bio- and geohelminths which drains into
and contaminates the Lena river, represents a health and
epidemiological safety hazard in the Sakha Republic.
This paper presents the results of a study into the parasitic
contamination in the sewage of the city of Yakutsk. Data show
that in the collected wastewater taken prior to treatment, as
well as in the sediments recovered from the grit chambers of
the water treatment plant, 100% of samples were
contaminated with eggs of the Ascaris and the
Diphyllobothrium species. Even after UV irradiation treatment,
viable roundworm and tapeworm eggs were observed in 18%
and 9% of samples, respectively.
We conclude that the wastewater desinvasion methods
employed in Yakutsk are ineffective at fully eradicating the
causative
agents
of
ascariasis
(roundworm)
and
diphyllobothriasis (tapeworm), and as such are insufficient for
the purposes of epidemiological safety with regards to the
aforementioned forms of helminthiasis.
Combating the spread of infectious diseases and
safeguarding bodies of surface water from being
contaminated by parasitic worm eggs and larvae requires
effective sewage disinfestation treatment [4]. Modern water
treatment infrastructure in large part succeeds in purifying
water of mechanical detritus, chemical pollutants and
pathogenic microorganisms. Improving water purification
technology allows treatment facilities to reduce the
concentration of particulates and organic matter, bacterial
pollution to improve water quality. However, even the most
efficient water cleaning technology cannot guarantee that all
potential forms of invasion are removed from sewage [5].
Keywords-propagative helminth forms; diphyllobothriasis;
contamination of the environment’s objects; sanitary
parasitological
monitoring
of
wastewater;
sanitary
parasitological indices of water quality.
I.
The purpose of our work was to conduct - on the
premises of the Yakutsk biological water treatment plant –
an analysis of an ecological and sanitary parasitological
monitoring of wastewater and its sediments for the existence
and extent of contamination by helminth eggs.
INTRODUCTION
Diphyllobothriasis risk is present in the Northern parts
of the USA, in Canada, France, Denmark, Sweden, Holland,
Finland, Germany and other countries. Infestation rate has
been linked to the prevalence of rivers and lakes situated in
temperate and cooler climates [1].
Materials and methods. Data collection, sampling, and
dynamic tests were conducted in 2015-2017, on the
premises of the Yakutsk station for biological treatment of
wastewater. Analyses of water samples and their sediments
were carried out at the city’s chemical-bacteriological
laboratory GUP Vodokanal (where ‘GUP’ stands for ‘state
unitary enterprise’). In the course of the undertaken research
study, the following methods were used - epidemiological,
sanitary parasitological, and statistical.
Up to 10 thousand cases of diphyllobothriasis are
reported annually in Russia. At 16.8% of all cases of
biohelminthiasis, it is the second most common parasitic
worm infection after opisthorchiasis (79.7% of cases) [2].
Diphyllobothriasis is the primary parasitic worm threat
in the Sakha Republic, responsible for 97.1% of
biohelminth-caused infections. Data for 2016 showed a
population-wide infection rate of 112.2 0/0000. This region
occupies a leading position among the subjects of the RF
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1009
Harbin, China•May30-June1, 2018
II.
Currently utilized methods of wastewater disinvasion
treatment in Yakutsk do not guarantee eradication of
parasites responsible for ascariasis and diphyllobothriasis.
RESULTS AND DISCUSSION
The station for biological treatment of wastewater is a
major ecological facility in the city of Yakutsk. Received
municipal and domestic sewage waters undergo mechanical
and biological treatments here. The uniqueness of the
facility lies in the fact that, due to the severe climatic
conditions of Yakutia and permafrost, all structures are
located in closed heated rooms on a pile foundation.
Elevated parasite levels in wastewater carries a negative
impact on the health and sanitation levels of the local water
sources.
Monitoring water quality in water bodies of primary and
secondary importance in the Sakha Republic (Yakutia)
between 2010 and 2016 indicates the continuing ambiguity
of the sanitary-parasitological situation in the region.
According to the latest official data, 2016 vs 2015 recorded
a jump of 67.5% (1.14 vs 0.77) in propagative parasitic
forms in the water sources of the monitored zone.
Sanitary and chemical analyses of wastewater at the inlet
and outlet from the treatment facilities are systematically
carried out at the station, as well as the study of its
sediments for 30 sanitary-chemical and 5 sanitaryparasitological indices.
Environmental conditions in large part explain the
prevalence of helminth parasitism in a human population.
Taking the extant data on helminth contamination of the
local environment, N.A. Romanenko proposed a model of
helminth-parasitic epidemiology reflecting mutual cause and
effect between the quality of the environment and the
incidence of parasitological infections [6]. Official health
statistics are clear on the longstanding presence of
diphyllobothriasis in the Sakha Republic. Cases are recorded
every year. Infection rates (IR) varied from a maximum of
241 0/0000 recorded in 2006 to a minimum of 112.2 0/0000 in
2016. Over the studied period, the regional multiyear
average rate (MAR) totaled 177.5 0/0000. Even though 2006
and 2009 both saw an increase in the rates of cases more
severe than MAR (by 40% and 20% respectively),
subsequent years witnessed a stable, secular decline in IR.
The mechanical and biological treatment of sewage
carried out at the Yakutsk biological treatment station
allows to reduce the content of pollutants that exceed the
maximum permissible concentrations to the normative
values for organoleptic, mechanical and sanitary-chemical
indices. At the same time, the results of laboratory studies of
wastewater samples by parasitological indicators in 2016
did not meet the norms of SanPiN (Sanitary Rules and
Norms) 2.1.5.980-2000 "Hygienic requirements for the
protection of surface waters" (See Table I).
TABLE I. CONTAMINATION OF MUNICIPAL-DOMESTIC DRAINS AND THE
EFFICIENCY OF THEIR DISINVASIA AT TEH BIOLOGICAL TREATMENT PLANT
IN YAKUTSK (2016)
Eggs of
helminths
of the
genus
Ascaris
Diphyllobothrium
Enterobius
Positive samples detected
(% to those examined)
Water samples
Sediment samples
From
Before
After
After
After
grit
treatment
biologiUV
filtering
chamber
(n=12)
cal
(n=5)
(n=11)
treatment
(n=3)
(n=12)
100
33,3
18,18
100
100
Epidemiological analysis of the regional population
showed a reduction in rates of diphyllobothriasis infection
by a factor of 2.1 over 11 years. However, comparing the
regional MAR rate in the Sakha Republic (177.5) to the
nationwide rate (6.4), a factor of 27.7, shows just how
serious the region’s helminth-borne parasitic problem still
remains [3].
a
100
16,67
9,09
100
80
16,67
8,33
0
0
0
a.
Of the Sakha Republic’s administrative districts, a full
85% rate as unsafe with respect to diphyllobothriasis. As
table 2 shows, ten districts are particularly hard-hit, with
rates of the infection there registering anywhere from 4 to 7
times the regional average (See Table II).
UV – ultraviolet irradiation
Our evaluation of the parasite contamination of
Yakutsk’s sewage showed that in water samples taken prior
to treatment and samples of sediments taken from the grit
chambers, 100% of such samples showed Ascaris and
Diphyllobothrium egg contamination. Mechanical filtration
of grit chamber sediments failed to remove any Ascaris and
only reduced Diphyllobothrium contamination to 80%.
Water samples treated with secondary mechanical filtration
and activated sludge showed a reduction in contamination to
only 33% (Ascaris) and 17% (Diphyllobothrium). UV
irradiation reduced contamination levels further to 18.18%
(Ascaris) and 9.09% (Diphyllobothrium).
TABLE II. ADMINSTRATIVE DISTRICTS OF THE SAKHA
REPUBLIC (YAKUTIA) WITH ELEVATED RATES OF
DIPHYLLOBOTHRIASIS (2016)
Enterobius eggs were found in 17% of wastewater
samples taken prior to treatment. Mechanical filtration and
biological treatment (with activated sludge) reduced the
contaminated samples down to 8%. After UV irradiation, no
viable pinworm eggs were found.
Name
Infection
rates 0/0000
Zhigansky
Kobiaysky
Olekminsky
Khangalassky
729,1
468,1
440,9
293,9
Exceeds by a factor of
Sakha
Russian national
Republic
average
average
6,5
4,2
3,9
2,6
175,5
113,4
105,3
70,2
It should be noted that a fair number of researchers
estimate the real rate of Diphyllobothrium latum infestation
of the population to be on average 3 times the reported
1010
number, since not everyone who is subject to this parasitic
invasionwill get diagnosed [1].
full elimination of the parasites responsible for ascariasis
and diphyllobothriasis, and as such cannot guarantee the
epidemiological safety of the water supply.
Helminth eggs and larvae can survive for a long time in
the environment such as bodies of surface water, and as
such pose persistent threat of infection to definitive (or
primary), paratenic (or intermediate), and additional hosts.
The widespread availability of propagative forms of
Diphyllobothrium latum in the surface waters of the region
is evidenced by the infection rates of fish by larvae. In the
middle regions of the Lena river, infection rates seen in pike
(Esoxlucius), burbot (Lotalota) and perch (Percafluviatilis)
by plerocercoids of Diphyllobothrium latum reached 39.1,
67.0 and 17.7% at the infestation rate of 8.29±0.81;
16.2±2.51; 1.6±0.16 respectively [7].
Evaluation of parasitic contamination and continued
sanitary-parasitological monitoring of wastewater serve as
the starting point for regulating the parasites’ ecosystem by
influencing the forms, which exist outside the host organism.
In turn, this should allow a greater degree of sanitary control
over surface water and the optimization of public health
measures to combat water borne diseases and parasites.
REFERENCES
[1]
Hotspots for diphyllobothriasis in the republic are
concentrated in the drainage areas of the Lena, Kolyma,
Indigirka, and Vilyuy rivers. Central Yakutia is host to a
concentration of river-borne diphyllobothriasis with
freshwater copepods serving as another vector. The coastal
zones of lakes and reservoirs are a biotope for
Diphyllobothrium latum, where the parasite matures through
its coracidium and procercoid stages [8].
[2]
[3]
[4]
Our contention is that the regional prevalence of
parasitic infection by Diphyllobothrium is the result of
insufficient disinfestation of wastewater and its sediments.
[5]
The situation is made worse by the natural and climatic
characteristics of Yakutia. Permafrost makes the
construction of a traditional system of storm drains
impossible in the city of Yakutsk. This in turn leads to
surface runoff from the city finding its way to nearby
aquifers, bypassing any existing water treatment facilities.
The resulting conveyance of parasitic worm eggs and larvae
greatly increases pollution of the Lena river with
propagative parasite forms and aggravates the
epidemiological threat.
[7]
[6]
[8]
We believe the reason for the insufficient ovicidal
effects of UV irradiation, and also for the reduced
effectiveness of UV lamps is the fact that their surfaces are
rapidly dirtied when in use.
One of the possible environmentally friendly (nonchemical) solutions to the problem of UV lamps getting
dirty, and also to the issue of cleaning wastewater of
parasites is the simultaneous pairing up of ultrasound with
UV lamps. Ultrasound keeps the lamps clean while
simultaneously weakening the cell membranes of helminth
eggs, making them more susceptible to destruction by UV
irradiation.
III.
CONCLUSION
Municipal-domestic wastewater contaminated with
propagative forms of bio- and geohelminths are one of the
factors responsible for the unfavorable sanitaryparasitologic condition of the Lena river, which in turn
degrades the epidemiological conditions of the entire region.
The wastewater treatment methods currently employed
at the Yakutsk sewage cleaning facilities do not guarantee a
1011
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Отзывы:
Авторизуйтесь, чтобы оставить отзывA very interesting article that addresses important environmental issues of the Sakha Republic. This region occupies a leading position among the subjects of the Russian Federation with intensive morbidity rates. The article says that the applied methods of water disinfection are ineffective and do not guarantee the complete destruction of pathogenic bacteria. This threat is dangerous not only for Russia, but also for the United States, Canada, France, Denmark, Sweden, Holland, Finland, and Germany.
The author of the work showed an excellent level of knowledge of theoretical positions on the chosen research topic, showed the ability to formulate his own point of view (theoretical position) based on analysis.
Wastewater and its sediments are epidemically significant in realizing the risk of infection of the population with parasitic diseases. An increase in the volume of discharged wastewater becomes a source of pollution of open water bodies, and pollution processes prevail over the processes of natural self-purification. According to available data, the number of pathogens of helminthiases, including those with a significant proportion of viable ones, in wastewater and sediments ranges from units to hundreds in l / kg and depends on the incidence of parasitic diseases in the population and animals in the region, climatic conditions, the degree and efficiency of treatment and disinfection of waste water, etc. The role of wastewater and their sediments in the spread of parasitoses is undeniable. This is, first of all, a transmission factor and an indicator of the presence of parasitic pathogens, reflecting the structure of the incidence of the population. Annually, on the territory of Russia, only sewage sludge up to 100 million m3 is formed, this is only 0.5-1% of the total volume of sewage.
This work is very interesting.