Membrane technologies are very popular both in drinking water and wastewater treatment due to their significant advantages. However, colloidal fouling is one of the main disadvantages of low-pressure membranes. Fine particle ferric oxyhydroxide effectively protected membrane and adsorb humates, phosphates, arsenates, etc. Dividing of adsorption and microfiltration into two stages was the recommended regime. Mixing with adsorbent was the first one and separation on the membrane was the second stage. The adsorbent with immobilized impurities formed protective layer on the membrane surface. The non-adsorbed organic matter was left on this thickness. During backwash, water flow removed the adsorbent with immobilized pollutants. Afterwards, membrane was as clean as before filtration.