There are numerous electric and human-powered reverse osmosis devices on the market. Provided they are functioning properly, these devices work by forcing water at very high pressures through semipermeable membranes. The membranes remove dissolved ions, molecules and solids as well as all larger particles including suspended impurities and microorganisms.
Reverse osmosis units are the only devices capable of making virtually any water drinkable, including seawater. Owing to their power demands, cost, size and weight, reverse osmosis devices are limited to recreational vehicles and boats. Some smaller human-powered units are useful for seakayaks and small sail and powerboats but even they are too large and heavy for general travel and recreation use.