Advanced oxidation treatment of pulp mill effluent for TOC and toxicity removals

The application of advanced oxidation technologies to the treatment of effluents from the pulp and paper industry: a review

“…A rapid decrease of toxicity has also been reported for several effluents from the pulp and paper industry (Catalkaya and Kargi 2008;Chang et al 2004;Pérez et al 2001;Reyes et al 1998;Yeber et al 2000). Furthermore, COD was particularly reported to be very efficiently removed (≈ 90%) from a bleaching effluent of a nonrecovered paper mill by TiO 2 photocatalysis (Toor et al 2007), and from an agroresidue-based soda bleaching effluent by both TiO 2 (COD removal ≈ 90%) and ZnO (COD removal ≈ 95%) photocatalytic treatments (Kansal et al 2008) (Table 4).…”

“…Additionally, Catalkaya and Kargi (2008) achieved an 84% TOC removal applying this treatment to pre-biologically treated effluents from the pulp and paper industry (Table 4); and Mounteer et al (2007) further reported the increase of organic matter content in the treated effluent after performing this type of treatment, which might have been caused by colloidal matter solubilization during the oxidative process. In short, about an average 10% COD removal enhancement could be expected when the photocatalytic treatment of pulp and paper mill effluents is assisted by the addition of H 2 O 2 (Figure 2).…”

“…All these trials reported COD removal improvements in comparison to a regular UV/TiO 2 treatment (Catalkaya and Kargi 2008;Chang et al 2004;Kumar et al ;Muñoz et al 2006;Pérez et al 2001;Rodrigues et al 2008 Particularly, this treatment led to a 50% COD removal after 6 h of irradiation when it was applied to an ECF effluent of a pulp mill, and a 50% TOC removal was finally achieved after 7 h of treatment (Pérez et al 2001); Table 4). Therefore, COD removal can be mainly attributed to organic matter mineralization.…”

“…In addition, although Catalkaya and Kargi (2008) reported good removal figures of organics (i.e. 80% TOC removal) by applying this treatment at basic pH to a biologically pretreated pulp and paper mill effluent, using 0.75 g·L -1 of TiO 2 at pH = 11 during 60 minutes (Table 4); working at a neutral pH produced better treatment efficiencies purifying effluents in a newsprint paper mill (Merayo et al 2013), as well as it also yielded an almost complete decolorization of a kraft pulp mill effluent (Gouvea et al 2000).…”

“…The efficiency of the TiO 2 -photocatalytic process, and therefore the required reaction time to maximize it, are influenced by the dosage of TiO 2 itself (Chang et al 2004;Tanaka et al 1999); that is, the degradation of organics is improved until an excessive catalyst dosage causes a shadow effect interfering with the transmission of UV light so the generation of electron-hole pairs cannot effectively occur (Catalkaya and Kargi 2008;Chang et al 2004). Particularly, an optimum dosage of 10 g·L -1 of TiO 2 has been reported for the treatment of lignin powder, resulting in the 50% reduction of the color within the first 10 minutes of reaction (Chang et al 2004); whereas the removal efficiencies of both color and DOC reached about a 90% when the process was extended up to 960 minutes.…”