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 Bangladesh • Worst cases in Bangladesh and West Bengal regions

Bangladesh Epidemic • Problem originated in the 1970 s – 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)

Bangladesh Epidemic • Tube well options: – Shallow Well – Deep Well • Deep Concerns – Renewability – Contamination from drilling? Construction Cost: $1000 Renewable: ? ? As Contamination: No Construction Cost: $100 Renewable: Yes As Contamination: Yes 3 m clay [As ] 100 m aquifer of gray sand Shallow Aquifer Clay Layer Deep Aquifer Southern Bangladesh 40 m aquitard marine clay Deep Sandy Aquifer

Bangladesh Epidemic • Arsenic Source: Geological – Rock, Clay, Peat and Sand potential sources – Increased [As] due to desorption from iron oxides • Change in p. H, 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. 01 mg/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

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

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: 1. Effectively removes [As] to a potable level – Less than 10 ppb 2. Is economically feasible in undeveloped situations – Bangladesh Average Per Capita Income is $450 3. Requires minimal technological understanding

Experimental Details • Three methods were used to treat the samples: 1. The STAR method – Fe. Cl 3 mixed into sample, poured through sand filter 2. The 3 -Kalshi method – Sample poured through sand, iron filings, and sand 3. Granular Ferric Hydroxide Column

STAR Setup Ferric Chloride Packet Water Sand Filter

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

GFH Column(s) Contaminated Water Treated Water

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 176 th 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 – – – 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 • GFH: Very difficult

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