Synergism of Novel Sequence Bio-ecological Process and Biological Aerated Filter for Sewage Treatment in Cold Climate

A lab-scale integrated treatment system including the novel sequence bio-ecological process (SBEP) and biological aerated filter (BAF) for a sewage mixture (chemistry laboratory wastewater and domestic sewage) was presented in this paper. The main objective of the study was to test the contribution of artificial aeration, recirculation ratio and mass concentration of steel slag on pollutant removal in winter when the plants are dormant. It had been shown that SBEP and BAF play different roles in removing contaminants from wastewater. During the airflow experiment, the removal efficiency of COD and TP in SBEP was higher than that in BAF, whereas BAF can compensate for the deficiency of SBEP where no significant improvement on ammonium nitrogen removal is observed. Yet, the removal efficiencies of COD, TP and NH4+ -N in SBEP could be improved apparently when different recirculation ratio or various mass concentration of steel were applied. Especially, when the airflow of 0.06 L·h−1, the recirculation ratio rate of 80% and the mass concentration of steel of 2.2-2.4 g·L−1 were applied, the highest efficiency of 94.6%, 77.9% and 80.7% for COD, TP and NH4+ -N were achieved, respectively. The integrated treatment system of SBEP and BAF was proved to be an effective wastewater treatment technique and a better alternative to treat domestic sewage.