Clarification of algae-laden water using electrochemical processes.

Area of Science:

• Environmental Science
• Water Treatment Engineering
• Applied Electrochemistry

Background:

• Algae contamination poses a significant threat to surface and drinking water supplies, especially in rural areas.
• There is a need for decentralized, inexpensive technologies for effective algae removal.
• Electrocoagulation (EC) combined with electroflotation (EF) presents a promising, low-power solution.

Purpose of the Study:

• To investigate the energy efficiency of a combined electrocoagulation-electroflotation (ECF) system for removing algae from simulated drinking water.
• To determine the optimal operating parameters for the ECF process.
• To assess the potential for simultaneous disinfection during algae removal.

Main Methods:

• An ECF system was designed and constructed to treat a simulated drinking water supply contaminated with algae.
• 18 experiments were conducted to evaluate water clarity improvement (measured by optical density at 750 nm).
• The relationship between energy consumption, gas bubbles (G), coagulant, and suspended solids (S) was analyzed, focusing on the gas-to-solids (G/S) ratio.

Main Results:

• The ECF system achieved over 95% improvement in water clarity at an energy consumption as low as 1.25 kWh m⁻³.
• An optimal gas-to-solids (G/S) ratio between 0.09 and 0.17 was identified for efficient algae removal.
• ECF produced chlorine gas in chloride-containing solutions, indicating a potential disinfection co-benefit.

Conclusions:

• The developed ECF system is an energy-efficient technology for removing algae from drinking water.
• Optimizing the G/S ratio is crucial for maximizing the effectiveness of the ECF process.
• ECF technology offers a dual benefit of algae removal and potential water disinfection.