Toxicity of conventional, elemental chlorine‐free, and totally chlorine‐free kraft‐pulp bleaching effluents assessed by shortterm lethal and sublethal bioassays

Abstract

The toxicity of nine effluents from Swedish kraft‐pulp mills using conventional, elemental chlorine‐free (ECF) and totally chlorine‐free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional‐softwood 30% ClO2; ECF‐softwood; TCF‐hardwood, for which all the samples were taken before and after secondary treatment; conventional‐softwood 8% ClO2; TCF‐softwood O3/H2O2; and TCF‐softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acute Nitocra spinipes test, the conventional‐softwood 8% ClO2 and the ECF‐softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test, N. spinipes was two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalga Ceramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2 was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects on N. spinipes and the Microtox bacterium.

Catalytic efficiency and stability of tertiary amines in oxidation of methyl 4-deoxy-β-L-threo-hex-4-enopyranosiduronic acid by hypochlorous acid

“…TCF bleaching technology was developed with the specific target to reduce the release of toxic chlorinated compounds in the environment (Reinstaller 2005). However, the pulp industry has not really shifted from ECF to TCF bleaching technology, because the ECF and TCF bleaching processes have been shown to produce effluents with similar toxicity (Tarkpea et al 1999). Other factors, such as pulp quality, bleaching costs, and energy consumption may favor ECF bleaching over TCF bleaching.…”

Towards an internationally harmonized test method for reproductive and developmental effects of endocrine disrupters in marine copepods

“…At the same time, Bengtsson (1978) proposed an acute toxicity test method with N. spinipes, which was applied to study 78 compounds including pesticides and industrial chemicals (Lindé n et al 1979) and adopted as national standard in Denmark in 1990(Danish Standards 1990) and in Sweden in 1991(Swedish Standards Institute 1991. These methods can also be used to determine the toxic potential of effluents from chemical plants (LindgaardJørgensen and Kusk 1984;Lehtinen et al 1984) and pulp mills (Nyholm et al 1991;Tarkpea et al 1999).…”

“…Effects of industrial effluents on reproduction have also been measured in static or semi-static tests (LindgaardJørgensen and Kusk 1984;Nyholm et al 1991;Tarkpea et al 1999). Bengtsson and Bergströ m (1987) used a flow-through system to study effects on reproduction of N. spinipes.…”

Anaerobic digestion in the kraft pulp and paper industry : Challenges and possibilities for implementation

“…In particular, bleaching effluents inhibited the methanogenic population, primarily related to the presence of halogenated organic compounds (Parker et al, 1992;Hall and Cornacchio, 1998;Yu and Welander, 1996). However, since then, most mills have replaced the use of elemental chlorine in bleaching with chlorine dioxide, leading to lower levels of adsorbable organic halogens (AOX) in the wastewaters (Stratton et al, 2004), thereby reducing their toxicity (Tarkpea et al, 1999). More recent publications on continuous AD on ECF bleaching effluents have indicated that the microbial population is able to adapt to the toxic or inhibitory compounds in these waters, reaching COD removal efficiencies of 45%-55% (Chaparro and Pires, 2011;Vidal et al, 2007) and AOX removal efficiencies of 40%-58% (Chaparro and Pires, 2011).…”