Treatment of kraft evaporator condensate using a thermophilic submerged anaerobic membrane bioreactor

摘要

The feasibility of using a thermophilic submerged anaerobic membrane bioreactor (SAnMBR) fornkraft evaporator condensate treatment was studied at 55 ^ 18C over 6.5 months. Under testednorganic loading rate of 1–7 kgCOD/m3 day, a soluble COD removal efficiency of 85–97% wasnobtained. The methane production rate was 0.35 ^ 0.1 L methane/gCOD and the produced biogasnwas of excellent fuel quality with 80–90% methane. A higher membrane fouling rate was relatednto the presence of a larger portion of fine colloidal particles (1–10mm). The thermophilic SAnMBRnwas sensitive to the presence of toxic compounds in feed and unexpected pH probe failuren(leading to a higher pH). Feed toxic shock caused sludge deflocculation and thus deterioratednmembrane performance. Operating the reactor as a conventional anaerobic reactor to wastensome of the fine flocs in treated effluent during the start-up process was an effective strategy tonreduce membrane fouling. The experimental results from this study indicate that treatment ofnkraft evaporator condensate is feasible in terms of COD removal and biogas production usingnthermophilic SAnMBRs but pre-treatment may be needed to remove toxic sulfur compounds andnmembrane fouling caused by the large portion of fine particles may be a challenge.