COD and nitrogen removal by biofilms growing on gas permeable membranes

摘要: Abstract A bioreactor was constructed and used to treat a synthetic wastewater containing ammonium acetate trace nutrients for about 190 days. The reactor aerated by means of bundles gas-permeable hollow-fiber membranes that were installed in the reactor. provided specific surface area 422 m2/m3 external rapidly became covered an active biofilm. membrane agitated internal gas recycle. bubbles water encouraged fiber–fiber contact intended control biofilm growth. Chemical oxygen demand (COD) removals excess 95% achieved 6 h nominal detention time. Nitrification developed complete oxidation influent evident within 20 Even though equipped with large area, consumed growing on surface. As result, dissolved (DO) dropped zero able support essentially denitrification. After 3 months operation showed excellent both COD inorganic nitrogen but performance could not be sustained. Excess accumulation eventually contributed deterioration process performance. This study demonstrates while aeration can provide simultaneous BOD N removal same reactor, modules/bioreactor must designed allow development thick biofilms. In addition, options controlling thickness need investigated.