This study analyzed the impact of socio-economic development and climate change on levels of faecal indicator bacteria in the Betna River in Bangladesh. Water samples were tested to measure E. coli and enterococci concentrations. A hydrodynamic model and microbial model were used to validate measured bacteria levels and simulate future scenarios. The models found that human waste contributed more bacteria than livestock. Future socio-economic changes like population growth and sanitation levels were found to have a greater impact on bacteria levels than climate changes like increased temperature and precipitation. Improved sanitation and wastewater treatment were recommended to reduce bacteria in the river.

1. Assessing the Impact of Socio-economic
Development and Climate Change on Faecal
Indicator Bacteria in the Betna River, Bangladesh
M. M. Majedul Islam

2. Study Area
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3. Untreated wastewater discharges in the river
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4. The river is widely used
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5. High burden of waterborne diseases
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6. Livestock
Surface
runoff
Humans
Sources and pathways of bacteria
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Microbes in surface water
Manure on
Land
Pit latrine/
septic tank
Domestic use/
Irrigation/bathing
Increased
Temperature
Increased
Die-off of
pathogens
Extreme
Precipitation
Flooding
Runoff
Socio-
economic
Factors

7. Objectives
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(Membrane filtration method)
Step 1: Measuring E. coli and enterococci
Step 3: Microbial modelling
(MIKE 21-ECOLab)
Step 2: Hydrodynamic modelling (MIKE 21)
Step 4: Scenario Analysis

8. Measured FIB concentrations
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9. Hydrodynamic model validation
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10. Probability
Density
Function
Tidal water level (mPWD) Discharge (m3/s)
Future Water levels and Discharges
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11. Future flooding scenario
0
5
10
15
20
25
30
35
40
45
50
Baseline
(2014-2015)
RCP 4.5
(2040s)
RCP 8.5
(2040s)
RCP 4.5
(2090s)
RCP 8.5
(2090s)
No.
of
Days
Water level
Discharge
Danger water level > 3.84 mPWD
Danger discharge level > 400 m3/s
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12. Water quality model validation
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13. 13
Modelled FIB concentrations for Betna River
Enterococci
(cfu/100ml)

14. Scenario development
Variable
S1
Sustainable
S2
Uncontrolled
Shared socio-economic pathway SSP1 SSP3
Population Slightly increased Strongly increased
Sanitation Strongly improved Current trend
Wastewater treatment Strongly improved Little improved
Livestock Slightly reduced Increased
Representative Concentration Pathway RCP4.5 RCP8.5
Temperature, precipitation, sea level Moderate increase Strong increase
Climate models IPSL/MPI IPSL/MPI
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15. Scenario analysis results
Islam et al. Submitted
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16. Relative contributions from different sources
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17. Relative impact of climate and Socio-economic factors
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0
100
200
300
400
500
600
700
800
Sustainable
scenario (2040)
Sustainable
scenario (2090)
Uncontrolled
scenario (2040)
Uncontrolled
scenario (2090)
E.
coli
(%)
change
Without SSP
Without RCP

18. Conclusions
 The surface water of Betna River is not suitable for
consumption, even not for bathing
 The model captured the spatial and temporal variations of
measured FIB concentrations well
 Humans contribute more to FIB in Betna river than livestock
 Future socio-economic change is more important than climate
change
 More intensive monitoring and inclusion of all possible
bacterial sources is recommended for a robust modelling
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19. Thanks for your
Attention !
After the graduation
ceremony, you all are
invited to attend the
symposium at Cafe
Loburg.
A reception will take
place at 5:30 PM at
Aula.
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20. Assessing the Impact of Socio-economic
Development and Climate Change on Faecal
Indicator Bacteria in the Betna River, Bangladesh
M. M. Majedul Islam