Pretreatment and in Situ Fly Ash Systems for Improving the Performance of Sequencing Batch Reactor in Treating Thermomechanical Pulping Effluent

Abstract

In this work, two methods were applied for improving the performance of activated sludge in treating the effluent of thermomechanical pulping process. In one attempt, the effluent of the pulping process was pretreated with 0.2 wt.% of fly ash (FA) at room temperature and 100 rpm for 1 h, and the FA-pretreated samples were further processed by a sequencing batch reactor (SBR) system. In another work, FA (0.2 wt.%) and activated sludge were mixed with the effluent simultaneously in an in-situ system. The results showed that FA asimilation would benefit the removal of non-biodegradable substances, and thus facilitate the decomposition of contaminants by activated sludge in both systems, especially in the in-situ system. The removal efficiencies of 96.1%, 99.1%, 95.2%, 90.51% and 99.5% were achieved for COD, BOD, TOC, lignin and sugar from the effluent, respectively. In addition, the sludge volume index (SVI) of the FA-pretreated and in-situ systems decreased to 100.7 and 75.5 mL/g and the effluent suspended ...