Membrane filtration (RO, NF, UF, MF) Application to water treatment

The United Nations' flagship water program, the World Water Assessment Program (WWAP), which brings together the World Health Organization (WHO) and UNICEF, estimates that every human being needs at least 20 to 50 L of clean water every day to satisfy his or her needs. Nearly 2 out of 10 people are still deprived of drinking water, and over a billion people are forced to consume potentially contaminated water. Water pollution from industrial, agricultural and domestic wastewater discharges has dramatic consequences. The most worrying of these is the spread of disease, with cholera, typhoid and dysentery at the top of the list. It is estimated that 80% of diseases prevalent in developing countries are directly linked to poor access to drinking water and sanitation.

Freshwater resources are finite: the foreseeable increase in population and industrial development raise fears of a breakdown in water resources with far more serious consequences than those that will result from the end of oil reserves. There are substitutes for oil, but not for water. By 2030, 47% of the population is expected to be water-stressed, compared with 40% today (source: UNESCO).

The quality of the water supplied and the quantity required are therefore the criteria that need to be reconciled when it comes to water treatment. Membrane separation processes (reverse osmosis RO, nanofiltration NF, ultrafiltration UF, microfiltration MF) are well placed to achieve these objectives. Because membranes act as a physical barrier, they can reliably produce high-quality water for human consumption and industry, whether from fresh or salt water. Introduced into wastewater treatment, these separation operations enable water to be recycled and/or reused, potentially solving the problem of quantity.

The glossary at the end of the article summarizes the definitions used in the article and those needed to understand it.