Abstract: Two-stage Sequencing Batch Biofilm Reactors were used to process anearobically digested pig farm wastewater. The installation was designed to have 3 operation modes, a, b and c, that is, in Mode a, the aeration/non-aeration ratio 1.5 h:0.5 h for the first stage reactor and 2 h:1 h for the second stage reactor, and the total aeration time 9.5 h; in Model b, 1 h:1 h and 1.5 h:0.5 h, and 9.5 h, and in Model c, 1 h:1 h and 2 h:1 h, and 8.0 h, to investigate effect of aeration/non-aeration ratio on treatment of wastewater and simultaneous nitrification and denitrification of nitrogen. Results show that when the operation had the temperature controlled in the range of 24-27℃,ρ(DO) at 2.5-3.0 mg•L^-1 during the aeration period, ρ(COD) and ρ(NH₃-N) at 700-800 mg•L^-1 and 90-100 mg•L^-1, respectively in the influent, Model a was the highest in efficiency with TN and NH₃-N removal rate being 58.5% and 68.2%, respectively, indicating that the combination of high aeration/non-aeration ratio with low aeration/non-aeration is more conducive to removal of pollutants in anaerobically digesting pig farm wastewater.

Key words: two-stage SBBR, digested piggy wastewater, aeration/non-aeration ratio, synchronous nitrification and denitrification