Treatment of synthetic Kraft evaporator condensate and thermomechanical pulp pressate using novel thermophilic and mesophilic bioreactors / by Meiru Zheng.

Abstract

A comparative study on the treatment of synthetic kraft evaporator condensate and thermomechanical pulp (TMP) pressate between thermophilic (55°C) and mesophilic (30°C) temperature was conducted using sequencing batch reactors (SBRs) and membrane aerated biofilm reactors (MABRs), respectively. The performance of thermophilic and mesophilic SBRs was evaluated in terms of chemical oxygen demand (COD) removal, sludge flocculating ability and settleability for these two types of wastewater. Sludge characteristics, including floc size distribution, zeta potential, morphological mapping, were evaluated for sludge from both SBRs. The performance of the thermophilic and mesophilic MABRs was evaluated in terms of COD removal for these two types of wastewater. The main results and conclusions are summarized as below ... The COD removal efficiency (40 ~ 80%) of MABRs was lower than that of SBRs (60 ~ 90%) for TMP pressate treatment. The COD removal efficiency of thermophilic MABR (40 ~ 65%) was slightly lower than that of mesophilic MABR (50 ~ 80%). Effluent suspended solids in treated effluents of MABRs was higher than that of mesophilic SBR, suggesting a significant detachment of biofilms from membrane surfaces and the need of biosolids separation after MABRs to improve the quality of treated effluents."--from Abstract.