Environmental Science Water Resources and Pollution Test 2026 – Complete Prep Resource

The technique relies on pushing water through a barrier to separate salt. In reverse osmosis, seawater is pumped under high hydraulic pressure against a semipermeable membrane. Water molecules pass through the membrane, while most dissolved salts and ions are blocked, producing fresh water on the other side and a concentrated brine on the feed side. The applied pressure must overcome the solution’s osmotic pressure to drive the flow, making pressure the key factor. Distillation separates salt by heating to evaporate water and then condensing it, which is a phase-change method, not a pressure-driven separation. Desalination is the broad term for removing salt from saline water, with reverse osmosis being a common pressure-driven method. The water table is simply the upper surface of groundwater, not a desalination technique.