Download Cryptosporidiosis For more information RIVERBANK FILTRATION

Cryptosporidiosis
Cryptosporidiosis is a parasitic infection caused
by Cryptosporidium, a protozoan parasite, and
spreads via the faecal-oral route. In humans
without an intact immune system, it can provoke
not only temporary, but permanent and lifethreatening diarrhoea. Although the infection was
identified only 30 years ago, it is a common
waterborne disease found worldwide.
(strained) by the fine sediments that constitute
riverbeds and the matrix of heterogeneous
aquifers. In this particular case, while other
drinking water treatment techniques fail,
implementing RBF is able to effectively control
the risk of oocysts reaching drinking water.
sedimentation analyses
RIVERBANK FILTRATION NETWORK (RBFN)
Removal of pathogenic
microorganisms by bank filtration
sieve analyses
100
Grainsize < d [% mass of total dry mass]
Cryptosporidium oocysts are present in high
concentrations in untreated as well as treated
sewage. For instance, one infected cattle can
excrete up to 1010 oocysts per day. Hence, the
micro-organisms are commonly found in open
water bodies.
90
80
70
size range of
Cryptosporidium oocysts
60
50
40
30
20
10
0
0,001
0,01
0,1
1
Grainsize d in mm
New Supply Channel
River Ganga (barrage reservoir)
Sizes of grains versus size of oocysts (Sandhu, 2007)
A collaborative initiative of
University of Applied Sciences Dresden (HTWD),
Dresden University of Technology (TUD),
DVGW - Water Technology Center Dresden (DVGW-TZW),
Stadtwerke Duesseldorf AG (SWD),
Uttarakhand Jal Sansthan (UJS),
Indian Institute of Technology Roorkee (IITR).
For more information
River Ganga at Varanasi (Sandhu, 2006)
Cryptosporidium oocysts are particularly of
concern due to their high infectivity (consumption
of only 10 oocysts can cause illness), longevity
(weeks to months survival in fresh water) and
resistance to conventional drinking water
disinfection methods such as chlorination
(WHO).
As Cryptosporidium oocysts are relatively large
in size (4 - 14 µm, i.e. larger than bacteria and
viruses), they can very effectively be filtered
The Coordinator
Cooperation Centre for Riverbank Filtration (CCRBF)
C/O Maintenance Division, Uttarakhand Jal Sansthan
Pant Dweep, Haridwar 249 401 (Uttarakhand), INDIA
Ph./Fax: 01334-262011
Email: [email protected]
Mr. Cornelius Sandhu
University of Applied Sciences Dresden
Department of Civil Engineering & Architecture
Division of Water Sciences - Riverbank Filtration Network
Friedrich-List-Platz 1, D-01069 Dresden, GERMANY
Ph.: +49-351-4622681, Fax: +49-351-4622195
Email: [email protected]
This publication is prepared by C. Sandhu, C. Syhre and T.
Grischek, University of Applied Sciences Dresden, Germany.
Funded by the German Federal Ministry of Education and Research (BMBF)
programme ‘India and Germany – Strategic Partners for Innovation’.
Introduction
Spread of waterborne diseases
Though the coverage of drinking water in India
has increased, 17 % of the Indian population still
does not have adequate access to drinking
water.
It is still a common mode to dispose sewage
without treatment into rivers. Additionally, animal
faeces – containing pathogens – from
agricultural lands and roaming animals are
introduced into water bodies.
Worldwide over 1.1 billion people lack adequate
water supplies (safe and affordable drinking
water) and about 2.6 billion people lack improved
sanitation.
Waterborne
diseases
cause
approximately 1.8 million deaths each year at a
global scale (WHO/UNICEF, 2006).
Bacteria
Waterborne disease
HUS, gastroenteritis,
Typhoid, gastroenteritis
Dysentery
Cholera
Leptospirosis
Gastroenteritis
Gastroenteritis
Pathogens
Enterotoxygenic E. coli
Salmonella ssp.
Shigella ssp.
Vibrio cholerae
Leptospira interrogans
Yersinia enterocolitica
Campylobacter jejuni
Poliomyelitis
Gastroenteritis
Jaundice, liver failure
Gastroenteritis
Viruses
Poliovirus
Rotaviruses
Hepatitus A virus
Norwalk virus
Giardiasis
Cryptosporidiosis
Amoebic dysentery
Protozoa
Giardia lamblia
Cryptosporidium parvum
Entamoeba histolytica
Riverbank filtration (RBF) offers a simple and
effective means to remove disease-causing microorganisms from the water, and for this reason has
been implemented in Europe for over 100 years.
Applied as alternative to direct surface water
abstraction in India, it reduces the risk of
waterborne diseases.
sewage
manured
fields
cattle
Pathogen removal processes during RBF (Syhre, 2007)
human and animal feces
Riverbank
Improved
Sufficient water
c o n t asanitation
m i n a t e for
d hygiene
filtration
drinking
water
flies
= barriers
hands
mouth
Barriers to the faecal-oral route (Syhre, 2007)
If river water is directly, and without sufficient
treatment, used as the source for drinking water,
there is no barrier for the transmission of
waterborne diseases. RBF can form such a
barrier.
Microbial analyses of riverbank filtrate from
abstraction wells on the River Rhine (Germany)
demonstrated a 99.9 % (3 log) removal of
coliform bacteria and the complete elimination of
Giardia and Cryptosporidium oocysts.
On the Upper Ganga Canal in Haridwar (India), a
reduction of the total coliform count by more than
99 % (> 2 log) in the riverbank filtrate was
determined by the RBFN in 2006.
Microorganism
Removal of pathogens by RBF
During underground passage pathogens are
removed due to the interaction of various
processes:
straining
(physical
filtration),
adsorption to biofilms and aquifer material,
grazing by other micro-organisms, being trapped
in immobile pore water and natural decay.
Especially the clogging layer plays a significant
role in limiting the transport of pathogens from
the river to the drinking water production well.
Log
removal
≥ 5.0
Coliform
bacteria
≥ 4.8
2.15 2.35
≥ 2.6
Enteroviruses
1.7
RBF location
Reference
River Rhine
(Remmerden, NL)
Missouri River
(Parkville, USA)
North Platte River
(Casper, USA)
Havelaar et
al., 1995
Weiss et
al., 2005
Gollnitz et
al., 2005
River Rhine
(Remmerden, NL)
River Meuse,
(Roosteren, NL)
Havelaar et
al., 1995
Medema et
al., 2000
Due to its efficiency in improving source water
quality, RBF can serve either as a pre-treatment
step or even as final treatment step before
disinfection.