Extraction of Humic Acid Followed by Coagulation with Natural Starch Coagulant for the Elimination of Color and COD from Stabilized Leachate

Refractory organics (humic and fulvic acid) are the prime factors for the dark brown color and higher COD of stabilized landfill leachate. Because of increased loading, seasonal and compositional variation, leachate treatment is a complicated issue. A blended mechanism of microfiltration-centrifugation for humic acid (HA) separation and coagulation was investigated through this study to determine the removal (%) of COD and color from stabilized leachate. The synthesized natural starch from the bio-waste of palm oil trunk (OPT) was applied through the coagulation process to validate the potential reuse of annually produced OPT bio-waste. The research outcomes reported a maximum of 1325 mg/l HA separation with 56% COD and 83% color removal through the current study. Electron microscopic analysis of starch, sludge, and HA revealed the amalgamation of flocs through bridging. UV–vis analysis proved the efficient degradation of HA, which eventually accelerated the removals. Fourier transform infrared (FTIR) spectrum analysis of HA and starch indicated the existence of respective functional groups, while the spectra of final effluent firmly identified the disappearance of higher molecular weight organic peaks. Therefore, the outcomes have recognized the effectiveness of this novel combination to eliminate the color and COD from matured leachate.