Microfiltration Membrane Cleaning 101
Microfiltration membranes have become one of the most promising technologies for water treatment. Other technologies from the past century have focused on neutralizing pathogens, removing contaminants, and improving the visible clarity of water. Membrane microfiltration and ultrafiltration are promising because they physically remove microbes and other particulates, but they are both susceptible to fouling.
Reasons for the Limited Information
Not much universal information is available regarding the cleaning of membranes. This is partially because many of the specialized cleaning chemicals are proprietary, and protocols vary according to the recommendations of each manufacturer. In addition, the reasons for fouling vary depending on the local environment and local water quality issues. Broad categories of membrane fouling include inorganic scaling, particles and colloids, microbial fouling and organic fouling.
Considerations with Chemical Cleaning for Membrane Microfiltration
When managing the cleaning of a membrane microfiltration system, it’s important to consider the interaction between the membrane material, the fouling contaminants and the cleaning chemicals. Fouling materials gradually obstruct the flow by occlusion, but they can also have electrostatic interactions with the filter. Hydrophobic interactions can also cause an attraction between the solutes and the membrane. An increase in pH, polarity, and charge density can promote an increase in electrostatic repulsion, which can be helpful in the cleaning process, separating the fouling materials from the membrane.
Types of Cleaning Chemicals
Caustic chemicals like sodium hydroxide (NaOH) can be used to promote solubilization and hydrolysis. Sodium hypochlorite (NaOCl) is one of several oxidants that can be used for oxidation and disinfection. Other oxidants or disinfectants include H2O2 and peroxyacetic acid. Citric acid and nitric acids are used for solubilization. Citric acid and ethylenediaminetetraacetic acid (EDTA) are both chelating agents. Finally, a variety of surfactants and detergents are used for cleaning by means of surface conditioning, dispersion and emulsifying.
The Importance of Thorough Analysis
Ultimately, there is no one-size-fits-all solution when it comes to cleaning membrane microfiltration systems. Some membranes are chosen for their higher chemical tolerance thresholds, which allows greater freedom in selecting cleaning chemicals. The sensitivity of a membrane can also impact the potential concentration of cleaning solvents and the frequency with which cleaning become necessary.
For professional consultation and improved efficiency, ask about M.W. Watermark’s field service contracts.
Learn more by visiting our membrane microfiltration webpage.
About M.W. Watermark
M.W. Watermark wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference in the water business, and as a result, make a positive difference to our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. We also specialize in rebuilding used water treatment equipment. Together, we can make a difference.