[Operation performance of membrane nitrification bioreactor for ammonia-containing wastewater]

The operation performance of membrane nitrification bioreactor to treat ammonia-containing wastewater as well as the capabilities of separation and filtration of polypropylene membrane modules were tested. The removal efficiency of ammonia was kept higher than 95% when the hydraulic retention time was set at 1 day, the influent concentration was increased up to 80 mmol (NH4+ -N) x L(-1) and the volume loading rate was increased up to 1.12 kg (NH4+ -N) x m(-3) x d(-1). The biomass in the reactor was accumulated from 5 g x L(-1) to 10 g x L(-1) within 50 days, which indicated that polypropylene membrane modules were efficient in retaining biomass. The biomass attached to the membrane also contributed to the conversion of ammonia and nitrite. When the hydraulic pressure was lower than 80cm, the increase of hydraulic pressure improved the permeation of membrane. However, when the hydraulic pressure was beyond 80cm, the increase of hydraulic pressure did not significantly improve the permeation of membrane. The permeate flux was the highest 2.51 (L x m (-2) x h(-1)) but the resistance was the lowest (2.63 x 10(-5)) m(-1) when the hydraulic pressure was about 20 cm. The results showed that the membrane nitrification bioreactor could be run normally without extra energy input.