Acrylic fiber wastewater treatment in a nested biofilm airlift suspension reactor

A treatability study on highly polluted, nitrogenous, complicated-composition wastewater from an acrylic fiber factory was conducted. The wastewater was treated using a nested biofilm airlift suspension reactor packed with skimmed walnut shells and plum-shaped carriers. The surface morphology of the biofilm was observed by scanning electron microscopy and electron microscopy. The images showed that the growth vector for biofilm thickness on the carrier was about 100~150 μm, and the shape of most bacteria was spherical or filamentary. The hydraulic retention time and superficial gas velocity were found to have remarkable effects on the biofilm reactor performance. At 10 h hydraulic retention time and 0.02 m/s superficial gas velocity, the chemical oxygen demand removal rate reached a maximum of about 58%. Under the same conditions, total nitrogen removal rate reached a maximum of about 70%. © Research India Publications.