Abstract
The performance and design of a dual-bag denitrifying module based on the selective permeability of polyethylene films were investigated. The module contained an inner polyethylene bag enclosing liquid organics (carbon sources) and an outer bag with a biofilm. Firstly, the permeation rates of methanol, ethanol, acetic acid, and propionic acid were set sufficiently high for the compounds to serve as carbon sources of the module. Secondly, two modules, one containing ethanol and one containing acetic acid were applied to the treatment of an inorganic nitrate medium. The stable denitrifying performances of both modules implied that alcohols and acids at high concentrations can serve as carbon sources of the above module without affecting the biofilm. Finally, the performance of the module set in an aerobic tank for an activated sludge process treating organic wastewater was examined. The water quality indices suggested that the denitrifying modules (of the fixed-biofilm type and attached-biofilm type) submerged in activated sludge are applicable to organic wastewater treatment without negative impact.
