Membrane Processes - Drinking Water

Originally, membrane water purification devices were only utilized in desalination projects. However, advances in membrane technology have made them a more popular alternative for eliminating germs, particles, and natural organic compounds that taint the taste and clarity of water.

Membranes used in water treatment are thin sheets of material that can separate impurities based on size or charge. Water passes through a membrane, but bigger particles, bacteria, and other pollutants are separated according on their size.

Some of these systems are pressure-driven, relying on water pressure to size-separate the particles. Sand, silt, clay, algae, bacteria, Giardia, and Cryptosporidium may all be removed with microfiltration, which has the highest pore size. Viruses can be removed via ultrafiltration. Nanofiltration systems provide nearly total virus protection, remove the majority of organic impurities, and can improve water hardness. Reverse osmosis systems use thick membranes to filter out practically all inorganic pollutants and all organic molecules except the tiniest ones.

Membrane technology is combined with the use of electrical current to separate pollutants depending on charge in electrodialysis. Unlike other membrane processes, during electrodialysis, the source water never flows through the membranes. It is not as widely employed as some of the other technologies described here in major water treatment facilities. Rather, it’s primarily employed in medical and scientific settings that require ultrapure water.

Maintenance is normally simple, although it might be costly because the main operation is to replace the membrane as needed. Membrane fouling and leaking are two common maintenance issues.

Find out more about water treatment here.