FIELD: pulp-and-paper industry. SUBSTANCE: two methods and their versions involving no gaseous chlorine are fulfilled through partial delignification of pulp until permanganate number about 10 or less and viscosity within the range from about 10 to about 13 centypoise are attained, after which partially delignified pulp is further delignified with a certain effective amount of ozone for a period of time sufficient to produce essentially delignified pump with permanganate number about 5 or less, viscosity about 5, and whiteness about 50%. The pulp thus obtained can be bleached with such bleaching agent as chlorine dioxide or peroxide to yield final product with whiteness about 65%, preferably 70-90%. Absence of chlorine allows regenerating filtrates from all stages except that where chlorine dioxide treatment is involved, when available. EFFECT: provided drainless process with considerably reduced environmental damage. 124 cl, 5 dwg, 30 tbl
