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Arsenic Removal From Well Water in Underdeveloped Countries

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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  1. Arsenic Removal From Well Water in Underdeveloped Countries Trygve Hoff Dr. Harold Walker, Advisor

  2. 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

  3. 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)

  4. 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?

  5. 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

  6. 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

  7. 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

  8. 10 year old children are developing the arsenicosis Cancers appear after 20 years Huge epidemic expected in the near future Health Risks

  9. 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

  10. 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

  11. 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

  12. Ferric Chloride Packet Sand Filter Water STAR Setup

  13. Contaminated Water Coarse Sand Iron Shavings Coarse Sand Fine Sand Wood Charcoal—Not Used Fine Sand Collected Water 3-Kalshi Setup

  14. Contaminated Water Treated Water GFH Column(s)

  15. 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

  16. Results • The GFH removed just over 80% [As]

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

  18. 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

  19. 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

  20. 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

  21. 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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