Optimization of the humic acid separation and coagulation with natural starch by RSM for the removal of COD and colour from stabilized leachate. Issue 11 (November 2021)

• Record Type: Journal Article
• Authors: Ahmed, Zaber; Yusoff, Mohd Suffian; Kamal, Nurul Hana Mokhtar; Aziz, Hamidi Abdul
• Is Part Of: Waste management & research. Volume 39:Issue 11(2021)
• Page Start: 1396
• Page End: 1405
• Publication Date: 2021-11
• Subjects: Bio-waste reusing -- stabilized leachate -- HA extraction -- natural starch -- central composite design -- response surface methodology; Factory and trade waste -- Periodicals; Refuse and refuse disposal -- Periodicals; Municipal engineering -- Periodicals; Déchets industriels -- Périodiques; Déchets -- Élimination -- Périodiques; Génie urbain -- Périodiques; 628
• DOI: 10.1177/0734242X211012775
• Languages: English
• ISSNs: 0734-242X

Abstract

The removal of concentrated colour (around 5039 Pt–Co) and chemical oxygen demand (COD; around 4142 mg L −1 ) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L −1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient ( R 2 = 0.98 and 0.96) and predicted R 2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.