You still may have to add pH and buffering-type chemicals. Now that the processes have been improved, they can be operated at lower pressures. They are now cost competitive with conventional treatments. There is an absolute pore size, which rejects anything greater than that process. The entire process is done without any chemicals.
Electrostatic rejection can also be important.
Rejection of particles smaller than the pore size may also occur. Particle removal may or may not result in a reduction of endocrine disruptors. If we use ultrafiltration, endocrine disruptors will not be removed. If we are using a conventional process where we add a salt, form a hydroxide surface, the secondary impact of particle reduction with coagulation also removes dissolved organic matter. When we started using disinfection processes we did not take into account things like taste and odor control or organic contaminant oxidation.