A preliminary evaluation of the use of treated mill effluent in hydrosulphite and peroxide bleaching of TMP - Initial results show it has little effect on brightness or chemical use

The use of biologically treated mill effluent to replace fresh mill water i n hydrosulphite and hydrogen pet-oxide bleaching of mechanical pulps was ex amined in laboratory studies. in hydrosulphite bleaching, complete replacem ent of fresh water with treated effluent had no effect on brightness gains. In medium and high consistency hydrogen peroxide bleaching, the results ra nged from none to small detrimental effects on brightness and peroxide cons umption, especially at very high NaOH charges.