Electrochemical Arsenic Removal Works in the Lab but Cannot Scale to Serve 140 Million Affected People

Arsenic contamination of groundwater affects an estimated 140 million people across 70 countries, with Bangladesh and West Bengal being the most severely impacted regions. UC Berkeley's ECAR (ElectroChemical Arsenic Remediation) technology, developed by Ashok Gadgil, demonstrated that passing current through iron electrodes in contaminated water generates iron hydroxide particles that adsorb arsenic, reducing concentrations from 500+ ppb to below the WHO limit of 10 ppb. The approach is simple, requires no chemical supply chain, and can run on solar power. Yet despite a successful patent application, field trials in Bangladesh, and licensing to an Indian operator, the technology has not scaled beyond small pilot installations. The patent application was abandoned, and the vast majority of affected people still drink arsenic-contaminated water.

Chronic arsenic exposure causes cancers (skin, bladder, lung), cardiovascular disease, and developmental effects. In Bangladesh alone, an estimated 43,000 people die annually from arsenic-related illness. The WHO calls it the largest mass poisoning in history. Affected communities are predominantly rural, low-income, and dependent on tube wells drilled into contaminated aquifers. Existing arsenic removal technologies either require chemical reagents that need continuous supply (coagulation-filtration), generate hazardous waste (adsorption media), or are too expensive for the target population (reverse osmosis). A solution must cost less than $0.01 per liter and operate without external chemical inputs.

ECAR generates its adsorbent (iron hydroxide) in situ by dissolving sacrificial iron electrodes, eliminating the supply chain for chemical reagents. Lab and field testing showed it removes both arsenic-III and arsenic-V to below WHO standards. However, scaling has stalled for operational and economic reasons: the iron electrodes require periodic replacement; the treated water contains suspended iron particles that must be filtered out; the process generates arsenic-laden sludge that must be safely disposed of; and operating a solar-powered electrochemical system requires some technical maintenance that is difficult to sustain in rural villages. The SONO filter (a simple iron-sand gravity filter invented by Abul Hussam) is cheaper and simpler but has limited capacity and must be replaced, creating a similar sustainability challenge. Solar-driven inline-electrolytic systems tested in West Bengal achieved 94% arsenic removal but require ongoing monitoring and filter maintenance. The common failure mode across all approaches is not the chemistry — it is sustaining operations in communities with no technical infrastructure, no government support for water treatment, and household incomes under $2/day.

The breakthrough needed is less about chemistry and more about system design for sustained operation with zero maintenance. A passive, zero-energy arsenic removal system with no moving parts, no consumable electrodes, and no waste management requirements would be transformative. Research into permeable reactive barriers (iron-based materials installed in well bore paths), biochar-iron composites, or naturally regenerating adsorbents could point toward maintenance-free solutions. Alternatively, a community-scale business model that bundles water treatment with revenue-generating services (e.g., mobile phone charging, agricultural information) could sustain operations economically.

A student team could design and test a gravity-fed, passive arsenic adsorption column using locally available iron-bearing materials (steel wool, iron filings, laterite soil) optimized for zero-maintenance operation over 6+ months, measuring arsenic breakthrough curves under realistic flow conditions. Alternatively, a team could develop a business model canvas for community-scale arsenic treatment in rural Bangladesh, identifying revenue streams, supply chains, and maintenance models. Skills in environmental engineering, water chemistry, materials testing, and social enterprise design would be most relevant.