Arsenic Contamination in South Arsenic Contamination in South- east Asia Region : east Asia Region : TECHNOLOGIES FOR ARSENIC MITIGATION TECHNOLOGIES FOR ARSENIC MITIGATION M. M. Feroze Feroze Ahmed Ahmed Ph.D., FIE, MASCE Professor of Civil/Environmental Engineering Bangladesh Univ. of Eng. & Tech., Dhaka, Bangladesh Outline of Presentation Outline of Presentation O Arsenic Contamination: Global and South Arsenic Contamination: Global and South- east Asia Scenario east Asia Scenario O Arsenic Mitigation Water Supply Technologies Arsenic Mitigation Water Supply Technologies O Arsenic Detection and Measurement Technologies Arsenic Detection and Measurement Technologies O Costs of Water Supply for Arsenic Mitigation Costs of Water Supply for Arsenic Mitigation
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Arsenic Contamination in SouthArsenic Contamination in South--east Asia Region :east Asia Region :TECHNOLOGIES FOR ARSENIC MITIGATIONTECHNOLOGIES FOR ARSENIC MITIGATION
M. M. Feroze Feroze AhmedAhmed Ph.D., FIE, MASCEProfessor of Civil/Environmental Engineering
Bangladesh Univ. of Eng. & Tech., Dhaka, Bangladesh
Outline of PresentationOutline of Presentation
OO Arsenic Contamination: Global and SouthArsenic Contamination: Global and South--east Asia Scenarioeast Asia Scenario
OO Arsenic Mitigation Water Supply TechnologiesArsenic Mitigation Water Supply Technologies
OO Arsenic Detection and Measurement TechnologiesArsenic Detection and Measurement Technologies
OO Costs of Water Supply for Arsenic MitigationCosts of Water Supply for Arsenic Mitigation
Worldwide Arsenic Contamination of Groundwater
WAIRAKI. NEW
ZEALAND
RONPHIBUN DISTRICT. THAILAND
RED RIVER DELTA VIETNAM
TAIWAN
KYUSHU. JAPAN
KAMCHATKAINNER MONGOLIA. CHINA
SHANXI PROVINCE. CHINA
XINJIANG PROVINCE. CHINA
BENGAL DESTA. WEST BENGAL. BANGLADESH
GREAT HUNGARIANPLAIN.
HUNGARY. ROMANIA
LAVRION PENINSULA.
GREECE
SOUTH-WEST ENGLAND
MASSIF CENTRAL. FRANCE
ASHANTI REGION. GHANA
ZIMBABWE
SOUTHAFRICA
CHACO-PAMPEAN PLAIN. ARGENTINA
NORTH-WEST ARGENTINA
ANTOFAGASTA CHILE
DOMINICA
HALIFAZ. NOVA SCOTIA
EL SALVADOR
ZIMAPAN VALLEY
LAGUNERA DISTRICT. MEXICO
WESTERN U.S.A.
ALEUTIAN ISLANDS
FAIRBANKS. ALASKA
BRITISH COLUMBIA
YELLOWSTONE PARK
NORTH-CENTRAL MEXICO
Arsenic-affected aquifers
Arsenic related to mining operations
Geothermal waters
LEGEND
OO Treatment of Arsenic Contaminated Water;Treatment of Arsenic Contaminated Water;
OO Alternative water Supply OptionsAlternative water Supply Options
OO Treatment of surface waterTreatment of surface waterOO Deep Deep tubewelltubewell;;OO Dug/Ring well;Dug/Ring well;OO Rainwater harvesting;Rainwater harvesting;
00 Piped Water Supply adopting any of the above Piped Water Supply adopting any of the above Technological OptionTechnological Option
Major Treatment ProcessesMajor Treatment ProcessesOO Oxidation and SedimentationOxidation and SedimentationOO Coagulation and FiltrationCoagulation and Filtration
OO AluminiumAluminium AlumAlumO O Iron saltsIron saltsOO Naturally Occurring Iron Naturally Occurring Iron
OO SorptiveSorptive FiltrationFiltrationOO ActivatedActivated AluminaAluminaOO Granulated Ferric Hydroxide/OxideGranulated Ferric Hydroxide/OxideO O Metallic Iron/ Iron OreMetallic Iron/ Iron OreOO Synthetic Composite Active MaterialsSynthetic Composite Active MaterialsO O Ion ExchangeIon Exchange
ALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS-- Surface Water TreatmentSurface Water Treatment
MultiMulti--Stage Roughing and Slow Sand FiltersStage Roughing and Slow Sand Filters
Raw Water
Clear Water
FilterSand
CoarseAggregate
Under DrainageSystem
To OverheadReservoir
X
XXX
Hydraulic Grade LineX
ALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS-- Surface Water TreatmentSurface Water Treatment
ALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS-- Surface Water TreatmentSurface Water Treatment
Source of Surface Water
Storage/ Sedimentation
Mixing Flocculation
Coagulants
Secondary Sedimentation
Filtration Disinfection
Chlorine
StorageTank
To Distribution
Small-scale Conventional Surface Water Treatment Plant
Silty clay
Arsenic ContaminatedShallow Aquifer (Sandy silt )
Arsenic-safeDeep Aquifer(Fine to medium sand)
Water Table
Clay Seal
Clayey Layer
Strainer
Sand Trap
Relatively Impermeable
Hand Pump
Manually Operated Deep Tubewell
RequirementsO Availability of deep
aquifers separated from shallow contaminated aquifers by relatively impermeable layers.
O The annular space of bore holes of the deep tubewellsis required to be sealed at the level of impermeable strata to avoid percolation of arsenic contaminated water.
-- DEEP TIBEWELLDEEP TIBEWELLALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS
(a) Conventional Dug Well (b) Well with Sanitary Protection
-- Dug/Ring WellsDug/Ring Wells
ALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS
-- Rainwater HarvestingRainwater Harvesting
Basic RequirementsAdequate Rainfall
-Intensity of Rainfall-Reliability of Rainfall
Distribution of RainfallSuitable Catchment areaStorage TankOperation and Maintenance
ALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS
Monthly Distribution of Rainfall of an Average Year
500
400
300
200
100
00J F M A M J J A S O N DJ F M A M J J A S O N DR
ainf
all I
nten
sity
, mm
/Mon
th
Month
Catchment Area
The minimum catchment area, A ( m2) required for collection of rainwater for N number of person to be supplied with q litre per capita per day is :
A = 0.365 q N / ( C I )
Rainwater Storage Tank
The minimum volume of storage tank V ( m3) required
V = 0.365 f q N
Where f is the fraction of available rainwater required to be stored
-- Rainwater HarvestingRainwater Harvesting
ALTERNATIVE WATER SUPPLY OPTIONSALTERNATIVE WATER SUPPLY OPTIONS
COST OF WATER SUPPLY BY ARSENIC REMOVAL TECHNOLOGYCOST OF WATER SUPPLY BY ARSENIC REMOVAL TECHNOLOGY