Seawater is pumped and passed through a 10m high tower like building with walls built from perforated blocks to encourage air circulation. These blocks act as windows to regulate the air flow in the tower. Approximately 15,000 bamboo slats are hung in the tower. Seawater is pumped repeatedly over the bamboo slats and circulated 6 to 7 times to increase the salinity of the solution (to around 20% salt content). This process takes about a week or more.