Comparison between sequential and simultaneous application of activated carbon with membrane bioreactor for trace organic contaminant removal

Abstract

The removal efficiency of 22 selected trace organic contaminants by sequential application of granular activated carbon (GAC) and simultaneous application of powdered activated carbon (PAC) with membrane bioreactor (MBR) was compared in this study. Both sequential application of GAC following MBR treatment (MBR-GAC) and simultaneous application of PAC within MBR (PAC-MBR) achieved improved removal (over 95%) of seven hydrophilic and biologically persistent compounds, which were less efficiently removed by MBR-only treatment (negligible to 70%). However, gradual breakthrough of these compounds occurred over an extended operation period. Charged compounds, particularly, fenoprop and diclofenac, demonstrated the fastest breakthrough (complete and 50-70%, in MBR-GAC and PAC-MBR, respectively). Based on a simple comparison from the long-term performance stability and activated carbon usage points of view, PAC-MBR appears to be a better option than MBR-GAC treatment.

Recent Advances in Water Management: Saving, Treatment and Reuse

“…They reported that adsorption onto activated carbon improved the overall removal of CBZ by as much as 40% [203]. Nguyen et al [210] also reported an overall CBZ removal of 98% by an MBR followed by GAC adsorption. When a sequencing batch reactor coupled to an external microfiltration membrane was investigated by Serrano et al [241], up to 93% CBZ removal was achieved following the addition of a single dose (1 g/L) of PAC directly into the bioreactor.…”

“…CBZ removal by MBR treatment followed by GAC filtration was investigated by Nguyen et al [210]. While MBR alone showed a removal of less than 20%, MBR-GAC achieved an extremely efficient removal of 98% [210]. This result demonstrates that GAC post-treatment could significantly improve the removal of PhACs, which are resistant to degradation by the activated sludge.…”

“…In a study by Nguyen et al [210], instead of using PAC as a post-treatment, it was added directly to the mixed liquor of an MBR. In that study, CBZ removal improved from 50% to 90% following the increase in PAC dose to MBR from 0.1 to 0.5 g/L [210].…”

Trace organic contaminants in biosolids: Impact of conventional wastewater and sludge processing technologies and emerging alternatives

“…It can also be used to mitigate membrane fouling (in MBRs) and facilitate the removal of TrOCs from the aqueous phase through sorption [86][87][88][89][90][91].…”

“…While the sorption of TrOCs on sorbents such as powdered and granular activated carbon (PAC and GAC, respectively) can help improve effluent quality, the conceptual expectation of 'bioregeneration' of the sorbents is often not accomplished [86][87][88][89], consequently necessitating periodic withdrawal of the spent adsorbent and its replenishment. The withdrawn sludge contains high concentrations of resistant TrOCs and needs to be properly treated and disposed.…”