Microfiltration is a filtration process which removes contaminants from a fluid or gas by passage through a microporous membrane. A typical microfiltration membrane pore size range is 0.1-10µm.

Historically, microfiltration has been used most prominently in the dairy industry for cheese production. It is also used to produce extended shelf life (ESL) milk by removing more bacteria than pasteurization alone.

Increasingly used in drinking water treatment, it effectively removes major pathogens and contaminants such as Giardia lamblia cysts, Cryptosporidium oocysts, and large bacteria.

Microfiltration membranes were first introduced to the municipal water treatment market in 1987 and applied primarily to waters that were relatively easy to treat. These were cold, clear source waters that were susceptible to microbial contamination. Low pressure membranes were selected to remove turbidity spikes and pathogens without chemical conditioning. As low pressure membranes increased in acceptance and popularity, users began to apply the technology to more difficult waters which contained more solids and higher levels of dissolved organics. Some of these waters required chemical pretreatment, including pre-chlorination. These shifts in water quality triggered change in low pressure membrane technology. New products and processes were introduced to deal with higher solids and chemical compatibility.

Chemical engineering | Drinking water | Filtration sur membrane