Desalination, Vol.247, No.1-3, 583-593, 2009
A novel application of automatic vacuum membrane bioreactor in wastewater reclamation
An automatic vacuum membrane bioreactor (AVMBR) equipped with an on-line air-water-chemicals backwashing system was developed for a purpose of the reclamation of domestic wastewater (300-800 mg-COD/L) and traditional Chinese medicine (TCM) wastewater (259-12775 mg-COD/L). The experimental setups were operated in pilot scale at hydraulic retention times (HRTs) of 3, 1 and 0.5 h for domestic wastewater, and at HRTs of 1, 3, 5 and 8 h for TCM wastewater. Experimental results indicated that membrane flux was able to resume as the fouled membrane modules being operated for 150 days were repeatedly subject to an air-water-chemicals backwashing procedure. Compared to a new membrane module, the contaminated membrane fluxes were resumed to 94.7% after the first cleaning, to 82.7% after the second cleaning and to 70.0% after the third cleaning at a vacuum value of 0.02 MPa. To meet reuse standard (effluent COD, less than 30 mg/L), the minimum HRT required by the AVMBR system was 1 h for domestic wastewater reclamation, and I h for less (hall 1000 mg-COD/L, 3.0 h for 1000-3000 mg-COD/L, and 5.0 h for 3000-6000 mg-COD/L TCM wastewater reclamation. However, when the TCM wastewater COD was larger than 6000 mg/L, an 8-h HRT operation of the AVMBR system failed to produce an effluent having a COD concentration less than 30 mg/L. It is concluded that the pilot-scale AVMBR system developed is feasible for the reclamation of domestic wastewater and TCM wastewater with a COD concentration less than 6000 mg/L.
Keywords:Air-water-chemicals backwashing;Automatic vacuum membrane bioreactor (AVMBR);Domestic wastewater;Traditional chinese medicine (TCM) wastewater;Wastewater reclamation