Electrocoagulation for Arsenic Removal: Field Trials in Rural West Bengal

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Electrochemistry

Background:

• Arsenic contamination in drinking water poses a global health risk, particularly in India.
• Conventional methods like ion exchange and reverse osmosis have limitations in cost and operation.
• There is a need for effective, affordable, and easy-to-operate arsenic removal solutions.

Purpose of the Study:

• To assess electrocoagulation with iron electrodes for arsenic removal from groundwater.
• To determine optimal operating conditions for efficient arsenic remediation.
• To evaluate the technology's performance in field trials for safe drinking water compliance.

Main Methods:

• Laboratory-scale batch experiments using iron electrodes in a monopolar configuration.
• Investigation of initial pH and electro-charge loading (ECL) effects on arsenic removal.
• Downstream filtration using sand or activated alumina to remove precipitates.

Main Results:

• Optimal electro-charge loading was found to be 25-30 Coulombs/L at pH 7.0 for an initial arsenic concentration of 0.2 mg/L.
• Field trials in West Bengal achieved significant arsenic removal (75-80%), meeting the WHO limit of 0.01 mg/L.
• Electrode passivation was observed, but can be mitigated by regular polarity reversal.

Conclusions:

• Electrocoagulation with iron electrodes is a technically effective, affordable, and operationally simple method for arsenic removal.
• The technology successfully produced safe drinking water meeting regulatory standards in field applications.
• Electrode passivation is a manageable challenge that can be addressed through operational adjustments.