Abstract
ABSTRACT
Lab-scale batch and continuous studies demonstrate that the immobilized fungal bioreactor, developed for treatment of bleach plant effluents, can be applied to wastewater consisting of foul condensate (FC) and caustic bleach filtrate (CBF). A study was conducted in two phases to investigate the combined treatment and potential internal utilization of methanol from foul condensate.
During phase 1, using the foul condensate and caustic bleach filtrate at the ratio they are typically present in a kraft mill as the bioreactor influent, a color reduction percentage of 76% (±5%) and adsorbable organic halides (AOX) reduction percentage of 70%( ±2%) were achieved using a residence time of one day. The performance of the bioreactor with respect to color and AOX reduction was very similar to that obtained from a control bioreactor operated under similar conditions but without condensate in the feed. There was no adverse affects on color and AOX reduction by Trametes versicolor by the constituents of the foul condensate.
In phase 2, the concentration of foul condensate and caustic bleach filtrate were optimized for optimum methanol reduction and bioreactor performance. With a combination of 30% v/v FC and 70% v/v CBF in the bioreactor feed, 76% color reduction, 56% AOX reduction, and 55% methanol consumption were obtained. It was also found that the presence of the methanol reduced the amount of carbon source required. The results of this study indicate that simultaneous treatment of caustic bleach filtrate and foul condensate by immobilized T. versicolor in a fluidized bed bioreactor is effective in reducing color, AOX, and methanol.
Key Words:
Biotreatment; foul condensate; caustic bleach effluent; fungi; Trametes versicolor; fluidized bioreactor; decolorization; AOX
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