The challenges and alternatives of water supply and sanitation in flood prone area: A case study for Bhuapur in Bangladesh

Abstract

Bangladesh is a riverine country and frequently affected by floods. Depending on location and sanitation conditions, drinking water sources are often contaminated during flood and many waterborne diseases like dysentery, diarrhea, typhoid etc. spread out. This research investigates potable water and sanitation condition in a flood affected area at Bhuapur in Tangail, Bangladesh. The various parameters such as colour (25 TCU), turbidity (128 NTU), total coliform (1800/100 ml) and faecal coliform (80/100 ml) for raw water collected from Halda river and during flood is much higher as compared to the Bangladesh standard limit. It is recommended that fabricated biosand filter should be used at flood prone area because it can significantly remove impurities such as turbidity over 95.28% and 87.82% for Halda river and flooded tubewell water respectively. The test results for other parameters like colour, total and faecal coliform have been compared with WHO guide lines and Bangladesh standards and found within the acceptable limits. Besides, alternative sanitary latrines have also been suggested to protect sanitation during flood.

Full text

THE CHALLENGES AND ALTERNATIVES OF WATER
SUPPLY AND SANITATION IN FLOOD PRONE AREA: A CASE
STUDY FOR BHUAPUR IN BANGLADESH
A. Hossaina, R. H. M. Juanib, S. Shamsc, Md. Rokonujjamand, KBM Shafiuddine
a Department of Civil Engineering,Chittagong University of Engineering and Technology (CUET), Chittagong 4349,
Bangladesh, E-mail: arif_hoss05@yahoo.com
b, c, e Department of Civil Engineering, Faculty of Engineering, Institut Teknologi Brunei, Jalan Tungku Link, BE1410,
Gadong, P.O. Box 2909, Brunei Darussalam, E-mail: rozeana.juani@itb.edu.bn,shams.shahriar@itb.edu.bn,
khairul.shafi@itb.edu.bn
d Department of Civil Engineering,Chittagong University of Engineering and Technology (CUET), Chittagong 4349,
Bangladesh, E-mail: rokon.ce05@ gmail.com
Keywords: Fabricated biosand filter, Flood, Climate Change,
Potable water, Sanitation.
Abstract
Bangladesh is a riverine country and frequently affected by
floods. Depending on location and sanitation conditions,
drinking water sources are often contaminated during flood
and many waterborne diseases like dysentery, diarrhea,
typhoid etc. spread out. This research investigates potable
water and sanitation condition in a flood affected area at
Bhuapur in Tangail, Bangladesh. The various parameters such
as colour (25 TCU), turbidity (128 NTU), total coliform
(1800/100 ml) and faecal coliform (80/100 ml) for raw water
collected from Halda river and during flood is much higher as
compared to the Bangladesh standard limit. It is
recommended that fabricated biosand filter should be used at
flood prone area because it can significantly remove
impurities such as turbidity over 95.28% and 87.82% for
Halda river and flooded tubewell water respectively. The test
results for other parameters like colour, total and faecal
coliform have been compared with WHO guide lines and
Bangladesh standards and found within the acceptable limits.
Besides, alternative sanitary latrines have also been suggested
to protect sanitation during flood.
1 Introduction
It is difficult to imagine any clean and sanitary environment
without water. In many regions throughout the developing
world, sources of water traditionally available in abundance
for domestic use are now disappearing [1]. Worldwide, an
estimated 768 million people remain without access to an
improved source of water – although by some estimates, the
number of people whose right to water is not satisfied could
be as high as 3.5 billion – and 2.5 billion (more than 35% of
the world’s population) remain without access to improved
sanitation [2]. The high rate of incidence of diarrhoeal
diseases and infant mortality in developing countries are
attributed to lack of water supply and sanitation [4]-[6]. An
estimated 801,000 children younger than 5 years of age perish
from diarrhea each year, mostly in developing countries [7].
Water and sanitation interventions are cost effective across all
regions of the world. These interventions were demonstrated
to produce economic benefits ranging from US$ 5 to US$ 46
per US$ 1 invested [8]. In rural areas, 1.7 billion people rely
on public taps, hand pumps, protected wells, protected springs
and rainwater [2]. In Bangladesh, about 55% of the rural
population use sanitary latrines while 4% still practice open
defecation [2]. In addition, another 16% use the so-called
home-made pit latrines that are constructed by placing a
squatting slab made of bamboo over a manually dug pit and
considered as unimproved sanitary latrine.
The South Asian region is highly sensitive to the
consequences of climate change. It is known to be the most
disaster prone region in the world having a huge population of
more than 1.3 billion [9]. Flood disasters are the most
frequent and devastating natural disaster in Asia and the
impacts of flood increased significantly despite our improved
ability to monitor and forecast them [10]. Heavy rainfall
resulting from climate change [11]; [12] will cause damage to
infrastructure, flooding and contamination of water supplies,
with consequent public health risks [13]. The effects of
Climate change in South Asian countries, especially,
Bangladesh, India and Nepal vary from the submergence of
low-lying islands and coastal lands to the melting of glaciers
in the Himalayas, threatening the volumetric flow rate of
many of the most important rivers of India, Bangladesh and
Nepal. This is challenging and raises a question of freshwater
availability for human being and ecosystem, and possesses
threat to water supply and sanitation [13]. Recurrent floods
are being widely mentioned as an impact of climate change,
alongside frequent and severe cyclones [14-15]. Bangladesh
is a densely populated riverine country faced with frequent
flooding due to lower elevations from sea, reduced gradient of
rivers, higher rainfall in the Ganges-Meghna-Brahmaputra
river basins followed by melting of glaciers in the Himalayas.
About 80% of the runoff in Bangladesh is from outside while
20% is contributed by local rainfall. Annual volume of runoff
is equivalent to about 12 meters of depth over Bangladesh’s

area under GBM basins. Flooding in Bangladesh is caused
mainly by spill from Brahmaputra and Ganges rivers and their
tributaries and distributaries during July to September as
shown in Figure 1. Flash floods from the hills occur in the
Meghna during the pre-monsoon months of April and May.
The poor, lower and lower middle class people are the most
vulnerable to flooding [13]. Lack of appropriate sanitation
facilities in flood-prone and high-water table areas is one of
the important contributing factors for health hazards. In flood-
prone areas, overflow of pit latrines during flood pose a high
health risk. A survey carried out by Kazi and Rahamn, 1999
[16] in flood prone area of Bangladesh found that out of the
total latrines, 41% were overflowed during the times other
than flooding. Of the overflowed latrines, 53 % overflowed
because of over-use, 40% overflowed by rainwater and 7%
due to rise of groundwater table. The major problems of
sanitation in flood-prone areas are surface water
contamination and loss of accessibility to the latrine during
flood. The present research looks for alternative potable water
supply and appropriate sanitation technologies for flood prone
areas in Bangladesh.
2 Methodology
The methodology consists of identifying the options for
potable water filter. Potential Biosand filter was studied and
modification was carried out to suit the case study area with a
Fabricated biosand filter. Water was collected and tested for
various parameters for raw water from Halda river and
flooded tubewell water; and treated water obtained from
Fabricated biosand filter. The test results were compared with
WHO and Bangladesh Standard. Since, potable water supply
only cannot ensure safe health therefore alternative sanitary
options were examined based on their suitability in flood
prone areas.
3 Study Area
The study area selected for this study is a flood affected area
in Bhuapur, Tangail. The study area is selected based on the
fact that it is a flood prone area and people are usually
deprived from appropriate sanitation facility. The surface
water sources such as pond, canal, and river are frequently
flooded in the study area and become contaminated by flood
water. Tubewell is the main source of safe drinking water in
many rural areas in Bangladesh, and so is in the study area.
Access to potable water is a major challenge due to damaged
roads. The community does not have sufficient clean/safe
drinking water. Maximum level of flood water in the study
area is between 1 to 2 meter, submerges the community
dwellings as shown in Figure 2. The study area lacks in
proper sanitation and sewerage line can be seen linked to the
main drain.
The back flow occurs in these sewerage lines resulting in
flooding of the household latrines during flood. Most of the
latrines in the houses are out of use and the affected
communities choose open defecation. The garbage gets
scattered all over the area due to flood water. There are
number of places where flood water is pooled and gets
stagnant, a potential source for vector borne diseases. Due to
scarcity of potable water and sanitation facilities, proper
hygiene practices are not possible to follow.
Figure 1. Inundation Map of Bangladesh
Figure 2. Tubewell submerged by flood water
The concentration of silt in turbulent water in the monsoon is
high. Similarly algae growth in stagnant water bodies in the
dry season is also very high. People’s unsanitary practices
greatly contribute to the deterioration of the surface water
quality in the study area. During flood access to safe
sanitation facilities becomes a difficult issue especially for
women who cannot move around much during the day.
Usually men go by rafts or boats to a distant place for
defecation. The main reason behind using alternate defecation
places during flood is that along with their houses, latrines
also get flooded and become unusable.

4 Alternative Potable Water Supply
The Fabricated biosand filter is a modified form of the
traditional slow sand filter that can be built on a smaller scale
using a plastic drum and operate intermittently. These
modifications make the fabricated biosand filter simple and
suitable for household or small group use. The filter can be
produced locally using materials that are readily available.
The Fabricated biosand filter should be used as part of a
multi-barrier approach which is the best way to reduce the
health risk of drinking unsafe water. In Fabricated biosand
filter, water is poured into the top of the filter as needed,
where a diffuser plate placed above the sand bed dissipates
the initial force of the water. When water is poured into the
top of the filter, the organic material is trapped at the surface
of the fine sand, forming a biological layer. Over a period of
one to three weeks, micro-organisms colonize the biological
layer, where organic food and oxygen derived from the water
abounds. Travelling slowly through the sand bed, the water
than passes through several layers of gravel as part of
mechanical process and collected through the tap located at
the base of the filter. The removal of pathogens occurs in the
Fabriacted biosand filter due to a combination of biological
and mechanical process.
Figure 3. Fabricated biosand filter
The selection and preparation of the media with sand and
gravel used in the Fabricated biosand filter is important to the
effectiveness and efficiency of the filter. The specification of
the filter materials are given in Figure 3. The materials which
do not pass through the 18.75 mm sieves are discarded. The
materials passing through 18.75mm sieves and retained on
12.5 mm sieve are used as large gravel layer, the materials
passing through 12.5mm sieve and retained on 10mm sieve
are used as separating small gravel layer the materials passing
through 1mm sieve and retained on 0.75mm sieve are used as
sand layer.
5 Results and Discussions
5.1 Water Supply
It normally takes a period of one to three weeks for the
biological layer to mature fully in a new filter. During that
time, the removal efficiency of the filter increases as the
biological layer grows. The Fabricated biosand filter has been
designed to allow for a filter loading of 40 liter/hour which
has proven to be effective in laboratory and field tests. The
amount of water that flows through the biosand filter is
controlled by the size of sand media contained within the
filter. If the rate is too fast, the efficiency of bacterial removal
may be reduced. If the flow rate is too slow, there will be an
insufficient amount of treated water available from the filter
to meet the needs of the users. Correct operation of the
Fabricated biosand filter requires a constant water level of
approximately 5 cm above the sand level during the pause
periods. Chemical analysis for raw and filtered water from
Hada River and flooded tubewell water were compared with
the treated water obtained from biosand filter as shown in
Table 1. The various parameters such as colour (25 TCU),
turbidity (128 NTU), total coliform (1800/100 ml) and faecal
coliform (80/100 ml) for raw water collected from Halda river
and during flood is much higher as compared to the
Bangladesh standard limit (colour 15 TCU, turbidity 10 NTU
and total and faecal coliform count nil). The high turbidity in
flood water is due to wide variety of suspended materials
which range in size from colloidal to coarse dispersions,
depending upon the degree of turbulence. The presence of the
coliform group is of great importance in the microbiology
quality analysis of water. The high presence of total coliform
is associated with contamination by sewage, other wastes,
human and animal excrement. The faecal coliform is due to
variety of intestinal pathogens e.g. bacteria, virus or parasites.
Therefore, Fabricated biosand filter was used for treating raw
water and analysed for various parameters such as colour (4
TCU), turbidity (6.04 NTU) and total coliform (0) which is
within acceptable limit as shown in Table 1. The comparison
between filtered and raw water is shown in Figure 4. The
Fabricated biosand filter has an efficiency of 95.28% and
87.82% for Halda river and flooded tubewell water
respectively. The presence of iron in water is physically unfit
for use. There is no iron present in the raw water but chloride
(30 mg/l) has been detected though it is within acceptable
limit (200-300 mg/l). The limitation of Fabricated fliter is that
it cannot remove dissolved compounds (e.g. salt, hardness,
arsenic, fluoride) and organic chemicals (e.g. pesticides,
fertilizers).
5.2 Sanitation
Raised latrines could be an alternative to the flood sensitive pi
t latrines in flood prone areas [17-19]. The characteristics and
advantages of various potential sanitary options in flood
prone area are discussed in Table 2. Step latrine is suitable
200mm empty Space
400 mm sand layer
62.5mm small gravel
75mm clear space
62.5mm large gravel
75mm clear space
14”

where space is limited for construction, plastic latrine is
suitable in terms of portability and affordability while
Urine Diversion Dehydration Toilets (UDDT) are suitable
where there is a threat of repeated pit collapse. UDDT
segregates faeces from urine reducing the volume for faeces
and producing less odours and therefore strongly
recommended for flood prone areas.
Figure 4. Turbidity Value of water from different sources.
Table 2. Proposed alternative sanitation option for floor prone
area
Types of
Sanitation
Characteristics
Advantage
Earth
stabilised
raised pit
latrine
This latrine is raised to avoid
floodwater intrusion into the
pit. Pit volume is increased
which renders the extended
life of the latrine. This latrine
requires more space area to
stabilise soil around the
raised portion of the pit
lining.
Suitable for areas
facing all four
types of flood
viz., river-water
flood, rainwater
flood, flush flood
and tidal flood
that occur in
Bangladesh every
year.
Step latrine
This latrine is also raised to
avoid floodwater intrusion
into the pit. Non-porous
lining is used above ground
level to prevent sullage
leaking. The extended
portion of the pit is often
made water-sealed by
plastering both sides.
Step latrine is
suitable for flood-
prone areas where
limited space is
available for
latrine
construction.
Mound latrine
In this type of latrine, pit
lining is also extended above
ground level to prevent the
latrine from flooding. A
mound of soil surrounds the
extended section of the pit.
However, it is not
recommended on clay soils
to avoid seeping out at the
base of the mound rather
than infiltrate the ground.
Suitable for flood-
prone areas where
space is limited
and watertight
linings are not
available.
Plastic latrine
Plastic latrine is the most
suitable for inaccessible
where concrete made latrine
component are less durable
due to transportation.
Easy to transport
and reusable. The
plastic pan is
affordable, costs
about 1200 taka
(15 USD) with a
life span for more
than 20 years.
Water quality parameters
FC
(n/100ml)
80
0
-
-
0
0
TC
(n/100ml)
1800
0
-
-
0
0
TDS
(mg/l)
120
50
70
30
Max-1000
Max-1000
Iron
(mg/l)
nil
nil
nil
nil
0.1-1
0.3-1
Alkalinity
(mg/l)
49
9.5
54
40
---
200-500
Cl
(mg/l)
30
3
7
5
Max-250
200-300
Turbidity
(NTU)
128
6.04
63
4.7
Max-5
Max-10
Color
(TCU)
25
4
20
5
Max-5
Max-15
PH
6.5
6.5
6.5
6.5
6.5-8.5
6.5-8.5
Table 1. Test results for different
parameters
Source
Raw
Fabricated
Raw
Fabricated
WHO standards
Bangladesh standards
After
filter
After
filter
Halda
river
Flooded
tubewell
water

Sand
enveloped pit
latrine
Sand envelope around the pit
is provided to limit disease
causing microorganisms
from leaking the water
supply. The risks of
contaminating groundwater
can be minimized by placing
a 500-mm thick envelope of
sand around the pit and
constructing an impermeable
pit bottom made from plastic
sheet or puddle clay. The
minimum horizontal distance
of separation from drinking
water sources should be
10m.
Suitable for flood
prone area.
Urine Diversi
on Dehydrati
on Toilets
(UDDTs)
UDDT is an elevated cons
truction, groundwater is m
uch better protected against
contamination of human
excreta. Additionally, remov
ing excreta is easier from dry
separation toilet than from a
pit latrine due to the dehydra
tion effect: urine can be colle
cted separately in closed cont
ainers, and the faeces can dr
y to as little as 20% of the ori
ginal volume after ash additi
on, ventilation or solar heatin
g.
Reduce the
repeated pit
collapse and
replace the toilet
conditions with
low odour and
flies.
5 Conclusion and Recommendation
Tubewells are the main source of water in Bangladesh. But
during the flood tubewell water is contaminated by flood
water. Fabricated biosand filter is a low cost household
biosand filter which can be used for removing impurities in
flood water, the performance of fabricated filter is good
having turbidity removal efficiency over 90% and its
maintenance is easy. Due to the poor sanitation system, flood
water mix with the sewage which is responsible for various
water borne diseases. Different elevated and plastic latrine
can be used for hygienic sanitation. It is now well established
that health education or hygiene promotion must accompany
sufficient quantities of safe water and sanitary disposal of
excreta. There is a need for multilevel and intersectoral
actions to achieve maximum impact through water and
sanitation interventions in flood prone areas of rural
communities. The Government, Nongovernment and Private
Organization should promote health education and provide
technological and economical facilities for Fabricated biosand
filter and different elevated latrines in flood prone areas.
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