A bubble column evaporator with basic flat-plate condenser for brackish and seawater desalination

Area of Science:

• Engineering
• Environmental Science
• Materials Science

Background:

• Small-scale desalination is crucial for remote regions with saline water access.
• Existing technologies may be too complex or energy-intensive for isolated locations.

Purpose of the Study:

• To develop and evaluate a novel bubble column-based humidification-dehumidification (HDH) system for small-scale water purification.
• To assess the performance of a simple flat-plate condenser integrated into the HDH system.

Main Methods:

• Construction and testing of a bubble column evaporator prototype.
• Design and experimental evaluation of a flat-plate condenser using polyvinyl chloride (PVC) pipe and copper sheet.
• Assessment of condenser performance under various conditions (passive, water-cooled, insulated, air-circulated).

Main Results:

• Consistent bubble evaporation rates of 80-88 ml/hour were achieved.
• A 1500 mm condenser model demonstrated 73% condensate recovery without external cooling.
• High salt removal efficiency was observed, with condensate salinity between 70-135 µS.
• Extrapolation suggests a 1 m² system could yield ~19 L/day.

Conclusions:

• The bubble column HDH system is a viable solution for small-scale desalination.
• Optimized condenser lengths (750 mm passive, 500 mm water-cooled) offer efficient performance and reduced material costs.
• The system shows promise for providing safe drinking water in remote areas.