Anti-fouling effect by internal air injection in plate-type ceramic membrane fabricated for the treatment of agro-industrial wastewater

The ceramic microfiltration membrane which composed of membrane body having macro pore and active layer having micro pore was fabricated successfully by the process including the sintering of tape-casted and laminated mixture of zirconia and polyvinyl butyral binder, and re-sintering after screen coating of zirconia. The average pore size and porosity of the fabricated membrane were 0.1855 μm and 40 %, respectively. A novel membrane microfiltration system adopting the fabricated ceramic membrane was also devised for the treatment of agro-industrial wastewater, and the effects of external air sparging and internal air injection were investigated. A significant improvement of permeability by external air sparging was not observed, and the permeate flux was about 20 L/m2/h. Despite the abnormal biomass status resulted from low water temperature and poor maintenance of facility, however, the system operated at the initial TMP of 0.4 bar and internal air injection intervals of 5 min showed excellent permeability of 100 L/m2/h. In addition, although several periodic internal air injections with inverse pressure was carried out, structural defects of fabricated ceramic membrane were not observed. Thus, it confirmed that the anti-fouling effect by optimum back-flushing strategy in fabricated ceramic membrane was effective for stability enhancement of agro-industrial complex wastewater treatment process suffering from maintenance.