1. Evaluating Technologies for Arsenic Removal: Experiences from Bangladesh
Md. Saifur Rahman
Executive Engineer, Arsenic Management Division
Department of Public Health Engineering (DPHE)
Government of Bangladesh
9/20/2018

2. Background
Approximately 96% of population use groundwater for drinking
However, in the 1990s widespread arsenic (As) contamination was detected
Estimated 22 million people drinking water with As greater than national drinking water standard of 50 µg/L
9/20/2018

3. Arsenic Mitigation Strategies
Awareness building
Testing of tubewell water for As by field kits
Marking of contaminated and uncontaminated tubewells
Patient identification and management
Providing Alternative Water Supply Options:
Groundwater: Deep tubewells, shallow dug/ring wells
Surface water: Pond Sand Filter (PSF)
Rain Water Harvesting
Arsenic Removal Technologies (ARTs)
9/20/2018

4. Two projects in Bangladesh to assess the performance of Arsenic Removal Technologies (ARTs)
Bangladesh Environmental Technology Verification – Support to Arsenic Mitigation (BETV-SAM)
Deployment of Arsenic Removal Technologies (DART)
9/20/2018

5. Bangladesh Environmental Technology Verification – Support to Arsenic Mitigation (BETV-SAM)
Project Partners:
Department of Public Health Engineering (DPHE)
Bangladesh Council for Scientific and Industrial Research
(BCSIR)
Ontario Ctr. for Environmental Technology Advancement
(OCETA)
Canadian International Development Agency (CIDA)
9/20/2018

6. Bangladesh Environmental Technology Verification – Support to Arsenic Mitigation (BETV-SAM) Project
Objectives of the BETV-SAM project include:
Independent, third party verification of technical performance of Arsenic Removal Technologies (ARTs) in Bangladesh
Long term monitoring and surveillance of verified ARTs that are deployed in Bangladesh
Building a sustainable capacity in Bangladesh Government agencies, third party laboratories and testing agencies, and other local stakeholders to carry out key functions associated with verification and monitoring
9/20/2018

7. Importance of independent, third party verification process:
Operating principles of the ART are described and have a sound scientific basis
Parties involved (proponent, test agency, analytical laboratory, verification authority) are technically qualified and independent of each other
The test data is credible and complete, QA applied
The Performance Claim (cumulative volume of treated water and ART media lifespan) is based on objective, scientific data and proven statistically, at the 95% confidence level
9/20/2018

8. ART Verification Process:
Technology Screening
Field Testing
Provisional Verification
Deployment
Rejection of Performance Claims
Monitoring
Bacteriological Findings
Waste Issues
Social Issues
Fiscal Outcomes
Final
Verification Report
(Arsenic)
Recommendations to the
Government of Bangladesh
ART Verification Process:
Screened over 40 vendor ARTs
Selected 12 ARTs for field testing
Field tested (technical team) 12 ARTs at 5 wells in areas with different water chemistries
Monitoring of community use to assess:
technical performance
social and economic aspects
Key items to note:
Many ARTs were screened and did not have sufficient technical data to support performance claim
12 most promising ARTs were selected for verification
Technologies used oxidation and sorption on different types of media for As removal
Some used flocculation, co-precipitation and filtration
Conducted field testing to assess the technical performance of the ARTs (i.e., consistently provide water with As-safe for a period of time)
Note that field testing comprised:
1. technical operation and testing by a technical team (NGOs, GoB supervision)
2. at 5 different areas of Bangladesh – different water chemistries (different As, Fe, PO4 ranges)
3. raw/treated water analysed (test kits and lab analysis)
4. results analysed, media life estimated - performance verified
4 ARTs were provisionally verified based on field testing
4 ARTs were then deployed to communities and the actual use by users was monitored:
Technical aspects monitored (raw/treated water chemistry)
Social issues (preference, etc.)
Financial aspects
9/20/2018

9. Results – General Findings
Most HH ARTs removed arsenic to < 50 µg/L, providing at least 45 L in 12 hours (cooking/drinking water for a rural family of 5)
However, most ARTs did not meet their stated performance claims for media life
Groundwater composition had a significant effect on the media life of a given ARTs (in particular, phosphate [PO4] concentration)
Spent filter media was not classified as hazardous waste according to tests included:
Toxicity Characterization Leaching Procedure (TCLP)
Dutch Total Available Leaching Procedure (TALP)
Discuss the different chemistries at sites. Full suite of analyses analysed, but main parameters influencing performance:
Arsenic concentrations (Higher As concentration = shorter media lifespan)
Iron:
helps to co-precipitate with As and increases performance
BUT media must be backwashed to prevent clogging
Higher Fe concentration = longer media lifespan
Phosphate – similar chemical properties to As and therefore competes with As (Higher PO4 concentration = shorter media lifespan)
Media lifespan estimated based on HH use of 15 L/day/person for family of 5
9/20/2018

10. Results – Technical Performance
Example: READ-F Household (HH) ART
READ-F performance verified at 5 locations with different water chemistry
Volume treated before breakthrough (i.e., As-unsafe) estimated
Phosphate (PO4) had significant influence on ART performance
Discuss the different chemistries at sites. Full suite of analyses analysed, but main parameters influencing performance:
Arsenic concentrations (Higher As concentration = shorter media lifespan)
Iron:
helps to co-precipitate with As and increases performance
BUT media must be backwashed to prevent clogging
Higher Fe concentration = longer media lifespan
Phosphate – similar chemical properties to As and therefore competes with As (Higher PO4 concentration = shorter media lifespan)
Media lifespan estimated based on HH use of 15 L/day/person for family of 5
9/20/2018

11. Results – Technical Performance
Example: SIDKO Community-scale ART
SIDKO performance verified at 5 locations with different water chemistry
Higher As-safe volumes produced (community-scale system)
Phosphate (PO4) also had significant influence on performance
Similar influence of water chemistry on the community system
Note the higher volumes treated to serve communities
Media life estimated based on assumed 2,250 L/day (50 HHs)
9/20/2018

12. Four Arsenic Removal Technologies (ARTs) received Provisional Verification
SONO
ALCAN
SIDKO
READ-F
Key items to note:
Based on field testing, only 4 of the ARTs had acceptable performance to consistently produce As-safe water for a long enough period to be practical for actual use in Bangladesh
3 household units (Sono, Alcan and Read-F)
1 community unit (SIDKO)
Price: $50 USD
$60
$100
$6,500
9/20/2018

13. Verification Certificates – Technical Performance
BCSIR issued Verification Certificates to successful proponents:
certify that performance of specific ART was verified
state that the ART must be deployed under the terms and conditions stated in the Conditions for Deployment
Key considerations for Conditions for Deployment include:
Water chemistry
Estimated volume treated before breakthrough (i.e., As concentration exceeds 50 µg/L) and when replacement of ART media is required
9/20/2018

14. Verification Certificates – Technical Performance
Key challenge was to provide Conditions for Deployment that were:
conservative enough to prevent users from drinking unsafe water after breakthrough (i.e., protect human health) *
applicable to the range of groundwater chemistry encountered in Bangladesh
maximized the lifespan of the ARTs
* Important note: rigorous monitoring and surveillance that would be required to identify when breakthrough occurs for an individual ART not practical (particularly for HH units)
9/20/2018

15. Verification Certificates – Technical Performance
Summary of Conditions for Deployment for four verified ARTs presented below:
Arsenic Removal
Technology (ART) As (µ
g/L) Fe
(mg/L) PO 4
Flow rate
(L/day)
Total volume
safe water (L)
Media lifespan
(months)
Household ARTs:
ALCAN
330 10 45
8,100 6
READ-F
500 50
36,000 24
SONO
750
Community ARTs:
SIDKO
2500
450,000
Raw Water Chemistry
Verified Performance
9/20/2018

16. Water Safety Plans (WSPs)
WSPs developed for each verified ART to support water safety from source to point of consumption
Key WSP components:
system assessment: describes the water supply (including process, intended uses, nature of consumers) and the technology
hazard analysis and control measures: includes a flow diagram to illustrate the process and identify hazards, and an analysis of those hazards
operational management: schedule to monitor the system and take corrective action when necessary
9/20/2018

17. Water Safety Plan (WSP) stakeholders
policy: technical experts, government (DPHE, local governments), NGOs, etc.
monitoring (NGOs and communities) and surveillance (Government of Bangladesh)
community workers: hygiene promoters, local community groups, providers of social service programs in rural Bangladesh
end users: communities, households, family members
9/20/2018

18. Deployment of Arsenic Removal Technologies (DART) Project
Project Partners:
Department of Public Health Engineering (DPHE)
UNICEF
Local NGO and consultant partners
Objectives of the DART project include:
Deploy HH and community-based ARTs to provide safe water to arsenic-affected communities
Conduct a social and economic assessment to analyze community acceptance of ARTs in the implementation area
9/20/2018

19. Results – Assessment of HH ARTs
Summary of questionnaires and surveys:
Arsenic Removal
Technology (ART)
% ARTs
in use
Est. daily
use (L/day)
Positive Comments
Negative Comments
ALCAN 80 30
Good look, size and
flow rate
Burden to clean, fragile tap,
clogs with iron
READ-F 71 24
Small size and
portable, good flow
rate
No reservoir (doesn't store
water), must continually be
filled, too expensive
SONO 77
Can store water,
looks good, low price
Slow flow rate, plastic is
fragile and breaks
Not all units were in use at time of surveys (generally within 6-12 months of deployment)
Daily use was less than the verification certificate – so the media may last longer than estimated
Positive and negative comments to all ARTs
Economic aspects must be carefully considered; even subsidized prices were considered high by the users. This had an impact on long term sustainability
9/20/2018

20. Results – Assessment of SIDKO Community ARTs
Results from 2 rounds of questionnaires and assessments mixed:
30%-41% judged to be “good” or “satisfactory”
41%-39% = “poor”
29%-15% = “failed”
Assessment criteria included:
accessibility of ART location, convenience of hours
absence of social conflict among users or resolution of conflict
number of user households, sharing of costs
competence of caretaker (demonstrated O&M; back-washing)
observed condition of the facility
9/20/2018

21. Current Status of ARTs in Bangladesh
Verification Authority:
One more HH ART (Nelima) received verification but now verification authority is not actively operating
Limited demand by proponents to receive verification
Community systems:
Over 300 SIDKO ARTs are reported to have been implemented
Estimated that over 80% of the ARTs are operational
Surveillance program not in place to assess technical performance
Household ARTs:
Limited demand created in the market
Some proponents are producing units, but at limited scale
9/20/2018

22. Conclusions
Independent verification is required to assess the technical performance of individual technologies; however, the verification process must be conducted in a timely manner to support creation of market demand and scaling up
ART performance is influenced by raw water chemistry and therefore will be variable in different locations:
Deployment conditions must be carefully considered and/or
Monitoring & surveillance required to identify breakthrough
In addition to As removal, WSPs must be implemented to support overall water safety for ARTs – in particular microbiological quality
9/20/2018

23. Conclusions cont.
ART media must be replaced regularly to provide As-safe water on a consistent basis
Government requires proponents to be responsible for collection and disposal of spent ART media; however, no guidance has been provided
Costs of HH ARTs influence market demand and long term sustainability
9/20/2018

24. Thank You
9/20/2018