The purpose of the present study was to examine the removal of ammoniacal nitrogen (NH4-N) from synthetic wastewater using limestone (LS) and granular activated carbon (GAC) mixture as low cost adsorbent. In batch study, optimum shaking and settling times were 150 and 120 min, respectively. The LS-GAC mixture ratio of 25:15 removed about 58% NH4-N. The smaller particle size of medium yielded higher adsorption capacity. The equilibrium adsorption data followed the Freundlich isotherm (R2 > 0.98) but it showed weak bond. Adsorption kinetics were well described by the pseudo second-order rate model (R2 > 0.93). The upflow column showed that higher flow rate and initial concentration resulted in shorter column saturation time. The study showed that the usage of GAC could be reduced by combining GAC with LS for the removal of NH4-N from wastewater; thus reducing the cost of treatment.
The focus of this research is to study the potential of nanofiltration membrane technology in removing ammonia-nitrogen from the aquaculture system. One of the major fabrication parameters that directly affect the separation performance is shear rate or casting rate during membrane fabrication. In this study, asymmetric polyethersulfone (PES) nanofiltration membranes were prepared at five different shear rates within the range of 67-400 s(-1). Membrane productivity and separation performance were assessed via pure water, salt and ammonia-nitrogen permeation experiments, and their structural properties were determined by employing the combination of the irreversible thermodynamic (IT) model, solution diffusion model, steric hindrance pore (SHP) model and Teorell-Meyers (TMS) model. The study reveals that the alteration of shear rate enormously affects the membrane morphology and structural parameters, hence subsequently significantly influencing the membrane performance. It was found that, membrane produced at the shear rate 200 s(-1) or equivalent to 10s of casting speed during membrane fabrications managed to remove about 68% of ammonia-nitrogen, in which its separation performance is the most favourable by means of highest flux and rejection ability towards unwanted solutes. Besides, from the research findings, nano-membrane technology is a potential candidate for the treatment of aquaculture wastewater.
This study evaluates the sugarcane bagasse derived activated carbon (SBAC) prepared by microwave heating for the adsorptive removal of ammonical nitrogen and orthophosphate from the semi-aerobic landfill leachate. The physical and chemical properties of SBAC were examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. The effects of adsorbent dosage, contact time and solution pH on the adsorption performance were investigated in a batch mode study at 30°C. Equilibrium data were favorably described by the Langmuir isotherm model, with a maximum monolayer adsorption capacity for ammonical nitrogen and orthophosphate of 138.46 and 12.81 mg/g, respectively, while the adsorption kinetic was best fitted to the pseudo-second-order kinetic model. The results illustrated the potential of sugarcane bagasse derived activated carbon for the adsorptive treatment of semi-aerobic landfill leachate.