Mechanistic and kinetic insights into the removal of soluble nanoparticles as templates for mesopores now permit scale-up of mesoporous polymer membranes. Investigations on the effect of pH and nanoparticle dissolution time showed that pH levels of 0 or 1 are necessary to enable fast pore template dissolution. Approximately 5 wt % of the originally applied nanoparticles remained in the membrane due to complete encapsulation by the polymer matrix but did not contaminate the permeate during prolonged use. We demonstrated continuous production of 17 m(2) (100 m length) of membrane using a commercial roll-to-roll coating unit. These membranes were successfully applied in gravitation driven water filtration. The rates of rejection of bacteria from heavily contaminated natural pond water were higher than 99.99%.