A continuous plasma treatment process is disclosed. The process may include providing at least one plasma treatment zone having a pair of electrodes with endless dielectric belts, each belt having a first and a second side that covers one of the electrodes. The process may include producing a non-thermal plasma in a space between the belts, and transporting a web material via the belts such that there is a width of exposed belt on either side of the web material. The process may include transporting the web material such that a side of the web material not in contact with the belts is treated in two passes through the at least one plasma treatment zone, while exposed parts of the belts transporting the web material are also treated. The process may include cleaning treated parts of the belts prior to the belts re-entering the at least one plasma treatment zone.