Aluminium removal from water after defluoridation with the electrocoagulation process

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Analytical Chemistry

Background:

• Aluminum compounds are common in fluoride removal, leading to elevated aluminum levels in treated water.
• Existing methods struggle to meet the World Health Organization (WHO) guideline of 0.2 mg/L for residual aluminum.
• Fluoride removal often involves aluminum-based coagulants, posing a challenge for residual aluminum control.

Purpose of the Study:

• To develop an effective method for fluoride removal that also controls residual aluminum concentration.
• To meet the WHO guideline for residual aluminum concentration (0.2 mg/L).
• To optimize the electrocoagulation process for minimal energy input while achieving target fluoride levels.

Main Methods:

• Electrocoagulation (EC) was employed for fluoride removal.
• Experiments were optimized to minimize energy input for achieving a target fluoride level of 0.7 mg/L.
• Bentonite clay was investigated as a coagulant in clariflocculation for aluminum removal.

Main Results:

• Aluminum concentration in water increased with higher energy input during electrocoagulation.
• Optimized electrocoagulation achieved target fluoride levels with minimal energy.
• Bentonite clay addition significantly reduced aluminum concentration below the WHO guideline.
• A bentonite dose of 2 g/L proved optimal for efficient aluminum removal.

Conclusions:

• A combined approach of optimized electrocoagulation and bentonite clay clariflocculation is effective for fluoride removal and aluminum control.
• This method successfully meets the WHO guideline for residual aluminum in treated water.
• Bentonite clay offers a viable solution for managing aluminum contamination in water treatment.