Clinoptilolite augmented electrocoagulation process for the reduction of high-strength ammonia and color from stabilized landfill leachate

The high-strength leachate produced from sanitary landfill is a serious issue around the world as it poses adverse effects on aquatic life and human health. Physio-chemical technology is one of the promising options as the leachate normally presents in stabilized form and not fully amendable by biological treatment. In this research, the effectiveness of natural zeolite (clinoptilolite) augmented electrocoagulation process (hybrid system) for removing high-strength ammonia (3,442 mg/L) and color (8,427 Pt-Co) from naturally saline (15 ppt) local landfill leachate was investigated. A batch mode laboratory-scale reactor with parallel-monopolar aluminum electrodes attached to a direct current (DC) electric power was used as an electrocoagulation reactor for performance enhancement purpose. Optimum operational conditions of 146 g/L zeolite dosage, 600 A/m² current density, 60 min treatment time, 200 rpm stirring speed, 35 min settling duration, and pH 9 were recorded with up to 70% and 88% removals of ammonia and color, respectively. The estimated overall operational cost was 26.22 $/m³ . The biodegradability of the leachate had improved from 0.05 to 0.27 in all post-treatment processes. The findings revealed the ability of the hybrid process as a viable option in eliminating concentrated ammonia and color in natural saline landfill leachate. PRACTITIONER POINTS: Clinoptilolite was augmented on the electrocoagulation process in saline and stabilized landfill leachate (15 ppt). The high strength NH₃ -N (3,442 mg/L) and color (8,427 Pt-Co) were 70% and 88% removed, respectively. The optimum conditions occurred at 140 g/L zeolite, 60 mA/cm² current density, 60 min, and final pH of 8.20. The biodegradability of the leachate improved from 0.05 to 0.27 after the treatment. This hybrid treatment was simple, faster, and did not require auxiliary electrolyte.

Characterization of titanium oxide optical band gap produced from leachate sludge treatment with titanium tetrachloride

This study investigated the coagulation performance of titanium tetrachloride (TiCl₄) for leachate treatment and preparation of titanium oxide (TiO₂) from generated sludge through calcination process at different temperatures and times. TiCl₄ with chitosan as coagulant aid employed to perform coagulation process on Alor Ponhsu Landfill leachate. Further calcination process was done to synthesize TiO₂ from produced sludge for photocatalytic applications. The studied factors included pH, TiCl₄ dosage, and chitosan dosage. The results indicated that maximum reduction in suspended solids was 92.02% at pH 4, 1200 mg/L TiCl₄, and 250 mg/L chitosan addition, and maximum reduction in chemical oxygen demand was 71.92% at experimental condition of 1200 mg/L TiCl₄ and 500 mg/L chitosan with pH 10. The maximum and minimum band gaps of prepared TiO₂ achieved at 3.35 eV and 2.75 eV, respectively. Morphology and phase analysis of prepared TiO₂ characterized using scanning electron microscope (SEM) and X-ray diffraction (XRD). The XRD spectrums showed the anatase phase at lower calcination temperature and the rutile phase at elevated temperature. The photocatalysis activity of produced TiO₂ investigated under UV irradiation and showed almost fast degradation similar to commercial TiO₂. The results indicated that TiO₂ powder was successfully prepared from generated sludge from TiCl₄ coagulation for photocatalytic applications.