Arsenic removal from well water in underdeveloped countries
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Arsenic Removal From Well Water in Underdeveloped Countries. Trygve Hoff Dr. Harold Walker, Advisor. Introduction. Arsenic contamination is a growing problem throughout the world. Argentina, Chile, China, India, Mexico, United States, Vietnam, Thailand and Bangladesh

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Arsenic Removal From Well Water in Underdeveloped Countries

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Arsenic Removal From Well Water in Underdeveloped Countries

Trygve Hoff

Dr. Harold Walker, Advisor


Introduction

  • Arsenic contamination is a growing problem throughout the world

  • Argentina, Chile, China, India, Mexico, United States, Vietnam, Thailand and Bangladesh

  • Worst cases in Bangladesh and West Bengal regions


Bangladesh Epidemic

  • Problem originated in the 1970s

    • UNICEF program to provide “safe” water

    • Arsenic wasn’t a known pollutant at the time

    • Saved thousands of lives from microbial pathogens, but …

  • 35-77 Million citizens at risk of arsenic poisoning (Out of a pop. of 125 Million)


Construction Cost: $1000

Renewable: ??

As Contamination: No

Construction Cost: $100

Renewable: Yes

As Contamination: Yes

3m clay

100m aquifer of gray sand

[As]

Shallow Aquifer

40m aquitard marine clay

Clay Layer

Deep Aquifer

Deep Sandy Aquifer

Southern Bangladesh

Bangladesh Epidemic

  • Tube well options:

    • Shallow Well

    • Deep Well

  • Deep Concerns

    • Renewability

    • Contamination from drilling?


Bangladesh Epidemic

  • Arsenic Source: Geological

    • Rock, Clay, Peat and Sand potential sources

    • Increased [As] due to desorption from iron oxides

      • Change in pH, oxidation/reductions, and competing anions

      • Excessive irrigation pumping in dry season with carbon-caused mobilization


Bangladesh Epidemic

  • The World Health Organization has set a guideline value of 0.01mg/l or 10 ppb

    • Bangladesh wells range from 0 to 1660 ppb


Health Risks

  • Arsenic poisoning appears after 10 years of consumption as arsenicosis

    • Can lead to:

      • Keratosis

      • Gangrene

      • Skin Cancer

      • Kidney Cancer

      • Bladder Cancer

      • Lung Cancer


10 year old children are developing the arsenicosis

Cancers appear after 20 years

Huge epidemic expected in the near future

Health Risks


Health Risks

  • Treatments are limited

    • Consumption of only arsenic free water

    • Zinc, Selenium, and Vitamin A for repair of the skin

    • Chelation therapy

      • Not proven to help patients


Research Goal

  • To find a temporary process that satisfies these objectives:

    • Effectively removes [As] to a potable level

      • Less than 10 ppb

    • Is economically feasible in undeveloped situations

      • Bangladesh Average Per Capita Income is $450

    • Requires minimal technological understanding


Experimental Details

  • Three methods were used to treat the samples:

    • The STAR method

      • FeCl3 mixed into sample, poured through sand filter

    • The 3-Kalshi method

      • Sample poured through sand, iron filings, and sand

    • Granular Ferric Hydroxide Column


Ferric Chloride

Packet

Sand Filter

Water

STAR Setup


Contaminated Water

Coarse Sand

Iron Shavings

Coarse Sand

Fine Sand

Wood Charcoal—Not Used

Fine Sand

Collected

Water

3-Kalshi Setup


Contaminated Water

Treated Water

GFH Column(s)


Results

  • The GFH column performed sub par

    • Possibly due to:

      • Channeling of the media

      • Inadequate contact time

      • Media grains too large—Insufficient surface area and sorption sites


Results

  • The GFH removed just over 80% [As]


Results

  • STAR and 3-Kalshi methods both successfully removed the arsenic


Economic Analysis

  • Average income is $450

    • Bangladesh is ranked 176th of 271 countries

  • Average Family size of 6 people

  • Consumption assumed to be 50 liters/day/person

    • Arsenic poisoning only through consumption

    • Only treat drinking and cooking water


Economic Analysis

  • STAR: Packets available for $4/family/year

  • 3-Kalshi: Iron available for$4.50/family/year

    • Iron fines available at $30/ton

    • 3 kg shavings for ~240 liters

  • GFH: Initial cost of $7.00 for two columns, materials $2.00/family/year afterward


Ease of Use

  • STAR: Simple

    • Drop packet in, pour through sand filter

    • Collect clean water

  • 3-Kalshi: Simple

    • Pour water into top bucket

    • Collect clean water

  • GFH: Very difficult

    • Requires technical training for a family member

    • Pump necessary for correct flow rate and pressure

    • Need a field test kit to determine when breakthrough has been reached


Conclusion

  • The STAR method is most efficient and cheapest, and is easiest to use

  • 3-Kalshi method is plausible, though doesn’t remove as much [As]

  • GFH is a good method, but best used in neighborhoods that have a treatment plant and technicians

  • Education of the population is KEY


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