Moving bed biofilm reactor for treatment of Kraft pulp effluent with high organic load rate

Abstract

<jats:p>The pulp industry uses more than 40 m3 of water per ton of pulp produced, generating high effluent flows. In general, it presents high concentrations of organic matter, color and ecotoxicity. The most widely used effluent treatment systems in the pulp industry are biological, including moving bed biofilm systems that are efficient in removing biodegradable organic matter. This work evaluated the removal of organic matter, total phenolic compounds, color and lignin derivatives in the treatment of Kraft cellulose effluent using the moving bed biofilm reactor (MBBR), and also evaluated the support media biofilm development by solid analysis and scanning electron microscopy. The parameters evaluated during treatment were: BOD5, COD, color, total phenolic compounds, lignin derivatives, and solids, with tests performed on organic loads from 0.7 and 8.9 kgCOD m-3 d-1. Organic matter removal remained stable, being over 80% to BOD5 and over 42% to COD. The color and the total phenolic compounds were removed up to approximately 7 and 28%, respectively. Over 19% removal of derivatives of lignin compounds was observed in both organic load rates. In the MBBR, biofilm was confirmed and enabled this biological system to treat the cellulose effluent in a stable way.</jats:p>

Microbiological diversity in an aerated lagoon treating kraft effluent

“…Figure 4 shows the organic matter removal in terms of BOD5 and COD. The average values of BOD5 removal were greater than 90%, which is in line with previous reports, 50 to 95% of BOD5 removal in systems and conditions similar to those employed in this study (Machado et al 2018;Peitz and Xavier 2020). The COD removal ranged between 40 and 60% during the 60 d of operation.…”

“…In the studies by Machado et al (2018) and Peitz and Xavier (2020), the nutrient ratio was 100:5:1; in the present study, it was 100:0.5:0.1, which is more similar to that of an AFL and to what is actually employed by the industry. The removal of biodegradable organic matter (BOD5) was greater in this study than in those with more use of nutrients.…”

“…Figure 5 shows that the TPC increased during the AFL treatment with an average of 26%. Some studies with kraft effluent showed an increase in total phenolic compounds in aerated biological systems (Chamorro et al 2009;Duarte et al 2018;Machado et al 2018;Melchiors 2019;Peitz and Xavier 2020).…”

“…The increase observed in the first 10 d of operation is related to the stabilization of the treatment system. The increase in color may be related to the process of biotransformation of chromophoric units and the condensation of color-forming compounds, without mineralization of the effluent (Lewis et al 2018;Peitz and Xavier 2020). Low color removal has been observed during treatment by aerated lagoons (Kamali and Khodaparast 2015;Peitz and Xavier 2020).…”

“…Pulp and paper production requires high water consumption, using 22 to 40 m 3 per ton of pulp produced (Hubbe et al 2016;Ibá 2020). The resulting effluents lead to environmental contamination due to the concentration of organic matter and compounds that are difficult to degrade (Kamali and Khodaparast 2015;Peitz and Xavier 2020). Cellulose effluent is treated in various ways, including biological systems, physicalchemical processes, adsorption, advanced oxidation, and membrane filtration (Majumdar et al 2019).…”