Continuous flow sequencing bed biofilm reactor bio-digested landfill leachate treatment using electrocoagulation-persulfate

Landfill leachate contains many complex components that have a negative impact on the environment when improperly discharged. This study is the first to treat landfill leachate (after continuous flow sequencing bed biofilm reactor (CF-SBBR) bio-digested) using electrocoagulation (EC) combined with persulfate (PS) on Al and Fe electrodes. The effect of some of the key parameters on the COD, Color, TOC and TN removal efficiencies as part of the EC-PS process were studied using the PS concentration, reaction time, initial pH, current density, and aeration rate. The results show that a PS concentration of 3 g/L improved the COD removal efficiency by 9.0 +/- 1.3 % at the Al electrode and 16.0 +/- 2.6 % at the Fe electrode. Aeration also improved the COD, TOC and color removal efficiencies by about 10.0 +/- 2.3 %, 8.0 +/- 1.7 % and 3.0 +/- 0.5 % at an optimal aeration rate 3.3 L/min. The optimal operation conditions for the EC-PS process were a PS concentration of 3 g/L, a pH of 2.0 (Al electrode), a pH of 4.0 (Fe electrode), a reaction time of 70 min, a current density of 35 mA/cm2 and an aeration rate of 3.3 L/min. The highest COD, color, TOC and TN removal efficiencies were 46.5 +/- 1.8 %, 95.8 +/- 2.4 %, 83.5 +/- 1.7 %, and 40.9 +/- 1.6 % at Al electrode and 54.4 +/- 2.3 %, 98.5 +/- 2.1 %, 78.6 +/- 1.5 % and 57.9 +/- 1.1 % at the Fe electrode. The EC-PS working mechanisms involve co-precipitation, an advanced oxidation process (AOPs) using oxidation radicals (HO center dot, SO4-center dot) and flotation. EC-PS is a promising method to treat bio-digested landfill leachate.

Automated summary

This study presents the use of electrocoagulation combined with persulfate to treat landfill leachate, demonstrating significant removal efficiencies for COD, color, TOC, and TN. By optimizing key parameters such as PS concentration, reaction time, and pH, the EC-PS process shows promising results in effectively treating bio-digested landfill leachate.