Granulated biomass fly ash coupled with fenton process for pulp and paper wastewater treatment.

The work describes the combination of granulated biomass fly ash (G _BFA ) with Fenton process to enhance the removal of adsorbable organic halides (AOX) from pulp bleaching wastewater. At optimal operating conditions, wastewater's chemical and biochemical oxygen demand (COD and BOD ₅ , respectively) and colour were also quantified, and operating cost of treatment assessed. For the first time, raw pulp bleaching wastewater was used to granulate BFA, instead of water, reducing the water footprint of the treatment. Five wastewater treatment setups were studied: (i) conventional Fenton process; (ii) G _BFA application; (iii) simultaneous application of G _BFA and Fenton process; (iv) sequential treatment by G _BFA followed by Fenton process; (v) sequential treatment by Fenton process followed by G _BFA . The latter yielded the highest AOX removal (60-70%), whilst COD was also reduced (≈15%) and wastewater biodegradability (BOD ₅ /COD) was enhanced from 0.075 to a maximum of 0.134. Another positive feature of the proposed solution was that G _BFA were successfully recovered and reused without regeneration, yielding similar AOX removal compared with fresh G _BFA . The operating cost of removing 1 g of AOX from the pulp bleaching wastewater by the optimal treatment setup (60-70% removal of AOX) was 14-26% lower than the operating cost of conducting Fenton process alone (50% removal of AOX).
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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