High organic removal of landfill leachate using a continuous flow sequencing batch biofilm reactor (CF-SBBR) with different biocarriers

Highlights: • CF-SBBR with different biocarriers was applied to treat landfill leachate. • Best COD, TOC, and NH₄⁺ removals were 79.6 ± 0.8%, 78.09 ± 1.9% and 77.5 ± 3.9% with MB biocarriers. • TN removal reduced with the increase of biocarrier's surface area. • The higher the surface area of the biocarriers, the greater anti-shock organic loading capacity. • Anammox candidatus was found with 0.5–1.0% in activated sludge, and 0.1–0.5% in biocarriers. Landfill leachate contains many pollutants that have a negative effect on the environment when improperly discharged. Thus the treatment of landfill leachate is a crucial issue, especially in the bigger cities in developing countries. In this study, landfill leachate is treated using a continuous flow sequencing biofilm batch reactor (CF-SBBR) with different biocarriers (non-carrier (NC), kaldness ^K1 (K1), mutag biochip 30™ (MB), and sponge polyurethane (SP)). The results show that the best COD, TOC, and NH₄⁺-N removal efficiencies were 79.6 ± 0.8%, 78.1 ± 1.9% and 77.5 ± 3.9% in the MB biocarriers tank with an aeration/mixing ratio of 1.3, a cycle time of 9 h and an organic loading rate (OLR) of 1.74 kgCOD/m³.d. The TN removal efficiencies was decreased when there was an increase in the biocarrier's surface area (NC > K1 > MB > SP). At the highest it was 46.1 ± 6.4%, where the aeration/mixing ratio was 1.3, the cycle time was 9 h, and the OLR was 1.52 kgCOD/m³.d. The higher the surface area of the biocarriers, the greater the anti-shock organic loading capacity of the biocarriers due to the formation of biofilm layers. The microbial communities in the CF-SBBR tanks were abundant with common phylum bacteria as in a conventional activated sludge system. Anammox candidatus bacteria was found to total 0.5%. This study concluded that CF-SBBR is an efficient method to treat landfill leachate.