ECAR is a highly effective ultra low-cost water treatment technology designed to bring locally affordable and sustainable arsenic-safe water to rural communities. In ECAR, or ElectroChemical Arsenic Remediation, ordinary steel plates use low voltage electricity to produce iron oxide (e.g. rust) particles in water that adsorb and trap arsenic. During the process, arsenite (which is more toxic and difficult to remove) is converted into arsenate, allowing the process to be highly effective under robust conditions. Treated water exceeds international WHO standards for arsenic and iron across many groundwater sources. The electrodes are cleaned by reversing the current, making operation and maintenance simple and non-hazardous. The technology was designed to work within a sustainable service delivery model that can cover the cost of an electricity source and still sell arsenic-safe water at a locally affordable price while simultaneously covering all costs.
The requirements for maintenance are low and electrode passivation can be limited by reversing voltage regularly. Operating ECAR is simple and non-hazardous: voltage is very low (about 3 V DC) and no corrosive chemicals are needed. ECAR can be operated by trained local community members.
Operating costs are extremely low (~ 0.04 USD/l), making it possible to sell the arsenic-safe water at a locally affordable price while simultaneously covering the expenses.
An estimated 60 million people in low-income countries in South Asia are exposed to naturally occurring toxic arsenic every time they drink from their local well. The arsenic crisis in the Bengal Basin has been described as the largest mass poisoning in human history. Arsenic is tasteless, colorless, odorless and its chronic ingestion leads to health problems, such as painful lesions or cancers, only in the long-run. Therefore, education is needed to raise awareness of the risks and to ensure the consumption of arsenic-safe water. Most solutions fail because their maintenance is being neglected.
In the preliminary testing at Jadavpur University (Kolkata), the prototype was placed in Dhopdhopi High School near Kolkata for a three-month field trial starting in October 2012. Prior to ECAR, this village school received pipe water for approximately 1 hour per day (inadequate to meet the needs of 2600 students) and supplemented it with groundwater, which was contaminated with about 250 µg/L of arsenic. The prototype consistently reduced arsenic levels below the WHO recommended maximum contaminant level (MCL) of 10 µg/L over several months of operation by a trained community member.
Educating young generations about the importance of water safety will give them the tools to make better choices for their communities in the future. Schools are therefore the natural choice to introduce the new water technology, and have been selected to test and operate ECAR 100L and 600L prototypes. Arsenic-safe water could potentially be included in the existing government sponsored midday-meal programs, opening up opportunities for subsidies to reduce the initial capital cost of a treatment center.
Material: Mild steel plates and an aluminium sulfate coagulant – both available in the region.
Costs: Costs for consumables plus amortized capital for ECAR are approximately 0.04 USD/l.
Assuming per capita consumption of 10L/day, this amounts to 1.46 USD per capita/year, or 10.22 USD per family/year, assuming 7 people per family. As comparison, it is estimated that an average family in West Bengal incurs a cost of 84 USD per year to consume water with more than 50 μg/L arsenic. This includes the cost of partially-effective preventative measures, medical expenditures, and loss of working hours due to illness, which can be attributed to arsenic poisoning.
Organization: Lawrence Berkeley National Lab - USA
Contact: Ashok Gadgil
Used by: India