Improvement in Aerobic Treatment of Digested Effluent and Process Selection

Addition of raw wastewater is an effective improvement measure for aerobic post-treatment of digested effluent. However, it is still unclear whether the sequencing batch reactor (SBR) or the anoxic/oxic process (A/O) is more suitable for the treatment of digested effluent. In this study, digested effluent mixed with 10%–40% raw wastewater was treated using the SBR and A/O. The nitrogen removal performance of the A/O was better than that of the SBR when 10%–20% raw wastewater was added. However, when the added raw wastewater proportion was 30%–40%, the nitrogen removal performance of the SBR was higher than that of the A/O. This may be due to the influence of BOD 5 concentration, mixed liquor recycling ratio and dissolve oxygen. The sludge activity test results showed that the SBR could easily carry out the partial nitrification-anammox process, whereas the A/O was more suitable for traditional nitrogen removal processes