A submerged membrane bioreactor (MBR) was applied to treat digested piggery wastewater (DPW).Rerovals of COD, ammonium-nitrogen (NH4-N), heavy metals and antibioties were studied when the hydraulic retention time (HRT) was gradually shortened from 12 d to 2.7 d, and the volumetric loading rates were increased from 0.4±0.1 kg-COD·m-3·d-1 and 0.13±-0.04 kg-NH4-N.m-3.d-1to 2.8±0.6 kg-CODm-3·d-1 and 0.49±0.07 kg-NH4-N ·m-3·d-1.Effluent concentrations of COD, Cu and Zn remained low and stable at all loadings.The effluent NH4-N concentrations remained below 10 mg L-1 at volumetric loadings of 0.33±-0.06 kgNH4-N ·m-3·d-1, while suddenly rose to 403 mg·L-1 at 0.49±0.07 kg-NH4-N ·m-3·d-1.No significant difference was observed between removals of sulfamethazine, sulfametho xazole and ciprofloxacin at different HRTs, but the removal efficiency of tetracycline antibiotics significantly decreased with the decrease in the HRT.The removal efficiencies of tetracycline, oxytetraeycline and chlortetraeyeline were 94.0 %, 93.2 % and 78.6 % at HRT of 12 ~ 8 d, respectively, 69.0~ 74.7 % at HRT of 4 d, and 40.5 ~ 61.8 % at HRT of 2.7 d.This study suggests that the volumetric loading of NH4-N be of the control factor when operating the MBR for the removal of NH4-N, and antibiotics.
Rui Liu Shaofeng An Dan Wei Xiaoyan Song Xinmin Zhan Lujun Chen Wei Zheng Yuan Zhao
Zhejiang Provincial Key Laboratory of Water Science and Technology,Department of Environment in Yang Zhejiang Provincial Key Laboratory of Water Science and Technology,Department of Environment in Yang Zhejiang Provincial Key Laboratory of Water Science and Technology,Department of Environment in Yang Zhejiang Provincial Key Laboratory of Water Science and Technology,Department of Environment in Yang College of Environment and Safety Engineering,Changzhou University,Changzhou 213164,China