{
    "title": "SONO Arsenic Water Filter",
    "inventor_name": "Abul Hussam",
    "publication_year": 2007,
    "device_name": "SONO Arsenic Water Filter",
    "goal": "Remove arsenic from drinking water to provide safe, affordable water.",
    "problem_addressed": "Arsenic contamination of groundwater in Bangladesh and Eastern India.",
    "concept_summary": "A low-cost, gravity-driven filtration system that uses a composite matrix of sand, charcoal, brick, wood and iron (or iron-based composite material) to adsorb and remove arsenic from well water without electricity.",
    "detailed_description": "The SONO filter consists of two polyurethane buckets lined with layers of sand, charcoal, brick fragments, wood chips and a composite iron matrix. Water is poured into the upper bucket, passes through the layered media, and arsenic-free water is collected in a lower bucket. The filter can produce ~20 L h^-^1 for household use and >100 L h^-^1 for community-scale models. The active material may include iron (68-92 % by weight) together with manganese, carbon, phosphorus, aluminum, silicon, cerium, sulfur, chromium, copper and zinc, embedded in a polymeric fabric matrix. The system is inexpensive (~US $35 per unit), lasts at least five years, and does not generate hazardous waste.",
    "category": "Other",
    "principles": [
        "Adsorption",
        "Filtration",
        "Ion exchange",
        "Gravity-driven flow"
    ],
    "scientific_domains": [
        "Chemistry",
        "Environmental Engineering",
        "Materials Science"
    ],
    "mechanisms_of_action": [
        "Arsenic adsorption onto iron-based composite particles",
        "Physical filtration through sand and charcoal",
        "Precipitation of arsenic species in the presence of iron oxides"
    ],
    "materials": [
        "sand",
        "charcoal",
        "brick fragments",
        "wood chips",
        "iron",
        "manganese",
        "carbon",
        "phosphorus",
        "aluminum",
        "silicon",
        "cerium",
        "sulfur",
        "chromium",
        "copper",
        "zinc",
        "polycarbonate",
        "polyester",
        "polypropylene",
        "polystyrene",
        "nylon",
        "cellulose"
    ],
    "energy_sources": [],
    "inputs": [
        "Contaminated groundwater",
        "Raw filter media (sand, charcoal, brick, wood, iron, polymers)"
    ],
    "outputs": [
        "Arsenic-free drinking water",
        "Spent filter media (solid waste)"
    ],
    "claimed_performance": "20 L h^-^1 per household unit; >100 L h^-^1 for community models; removes >99 % of arsenic; filter lasts >=5 years at a cost of ~=US $35.",
    "experimental_evidence": "Distributed >30,000 units in Bangladesh; peer-reviewed studies (J. ES&H 2007) report filtration capacity ~=30 mg As per gram of active material; field measurements show arsenic concentrations reduced to below WHO limits.",
    "replication_status": "In commercial use in Bangladesh and other countries; multiple field deployments and independent studies confirm performance.",
    "keywords": [
        "arsenic removal",
        "water filtration",
        "gravity filter",
        "composite iron matrix",
        "low-cost water treatment",
        "Bangladesh"
    ],
    "related_technologies": [
        "slow sand filter",
        "ceramic water filter",
        "iron-oxide adsorption media",
        "activated carbon filter"
    ],
    "controversy_level": "low",
    "confidence_score": 0.93,
    "practicability_score": 0.86,
    "fringe_score": 0.08,
    "evidence_strength": 0.78,
    "risk_score": 0.07,
    "trl_estimate": 7,
    "source_urls": [
        "http://www.pittsburghlive.com/x/pittsburghtrib/news/cityregion/s_498933.html",
        "http://chemistry.gmu.edu/faculty/hussam/Arsenic%20Filters/ESH%20ARSENIC%20FILTER%20PAPER%202007.pdf",
        "https://www.nae.edu/Publications/Bridge/V38N2/ArsenicFiltersforGroundwaterinBangladeshTowardaSustainableSolution7722.aspx",
        "http://www.designother90.org",
        "http://www.pittsburghlive.com/x/pittsburghtrib/news/cityregion/s_498933.html"
    ],
    "organizations": [
        "George Mason University",
        "SONO Laboratory (Bangladesh)",
        "Grainger Foundation"
    ],
    "applications": [
        "Household drinking water purification",
        "Community water supply in arsenic-affected regions"
    ],
    "limitations": [
        "Finite filter lifespan (~=5 years) requiring replacement",
        "Flow rate limited by gravity and media porosity",
        "Performance may vary with arsenic speciation and water chemistry"
    ],
    "open_questions": [
        "Long-term durability of the composite iron matrix in varied climates",
        "Effectiveness against different arsenic species (As(III) vs As(V))",
        "Optimal disposal or regeneration of spent filter media"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "\"The filters are inexpensive to produce and easy to use. Once water is drawn from a well, it is poured directly into the SONO filter. The clean water is then collected by a bucket attached to the filter, which can produce 20 liters of arsenic-free water per hour.\"",
        "\"Since he developed the filter, he has distributed 30,000 of them, most for free.\"",
        "\"A filtration capacity of approximately 30 mg of target per gram of embedded active material may be exhibited.\"",
        "\"The filter removes almost every trace of arsenic from well water.\"",
        "\"The filters are made from indigenous materials and cost about US $35, lasting at least 5 years without presenting a toxic waste disposal hazard.\""
    ]
}