At Östrand’s pulp mill, production has been TCF (Totally Chlorine Free) since 1996 when the old bleaching plant was replaced by the modern facility. Operating totally chlorine-free means that no chemicals containing chlorine are used in bleaching.
TCF means Totally Chlorine Free bleaching, meaning that no chlorine at all is used in the bleaching process.
This bleaching method does not produce chlorinated substances. The bleaching chemicals hydrogen peroxide and ozon, have only water and oxygen as rest products.
TCF also give opportunity to low water usage and totally closed processes which increases energy efficiency and results in lower emissions to water.
The main alternative to TCF bleaching is ECF bleaching. ECF denotes Elementary Chlorine Free bleaching, which means that chlorine dioxide (ClO2) is used instead of chlorine gas (Cl2). ECF forms chlorinated substances, however, in lesser quantities than those produced during chlorine bleaching. This bleaching method is better than chlorine bleaching, which produces high levels of organochlorine effluents (AOX), such as dioxins. Although modern ECF processes produce relatively low levels of AOX, the majority of the world’s bleaching plants are of the older model, and therefore, produces relatively high levels of AOX. The only way to entirely avoid the formation of AOX is to use TCF.