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

Abstract 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.

摘要 制浆工业每吨纸浆的生产耗水量超过40立方米，同时产生大量废水。这类废水普遍具有高浓度有机物、高色度与生态毒性特征。制浆工业中应用最广泛的废水处理工艺为生物处理法，其中移动床生物膜系统对可生物降解有机物的去除效果优异。本研究采用移动床生物膜反应器（Moving Bed Biofilm Reactor, MBBR）处理硫酸盐法制浆废水，对其中有机物、总酚类化合物、色度及木质素衍生物的去除效果进行了评估；同时通过固体分析与扫描电子显微镜（Scanning Electron Microscopy, SEM）对载体填料上的生物膜生长情况进行了表征。本研究考察的处理参数包括五日生化需氧量（Biochemical Oxygen Demand, BOD5）、化学需氧量（Chemical Oxygen Demand, COD）、色度、总酚类化合物、木质素衍生物及固体物，实验设置的有机负荷范围为0.7至8.9 kgCOD·m⁻³·d⁻¹。有机物去除效果保持稳定：五日生化需氧量去除率超过80%，化学需氧量去除率超过42%。色度与总酚类化合物的最高去除率分别约为7%与28%。在两种有机负荷条件下，木质素衍生物的去除率均超过19%。本研究证实了MBBR系统中生物膜的形成，使得该生物处理工艺能够稳定处理制浆废水。