Axial vibration mode of coupled liquid-structure-gas system in a rigid cylindrical container

This paper describes the axial vibration analysis of a closed ends rigid cylindrical container containing liquid and gas which separated by a thin circular plate at their interface. The liquid depths inside the container were varied and then the mode of vibration and the natural frequencies were analyzed. The natural frequencies obtained experimentally were compared favorably with those of commercial finite element analysis software, ANSYS. The vibration mode of the liquid-structure interaction of the tank system can be visualized from the software post processing animation/plot. The visualized modes are also consistent with the measurement by the respective experimental transducers. It was found that strong coupling predominantly occur between liquid and structure. In weak coupling conditions, the modes are predominantly gas mod

Integration of Copperas and <i>Moringa oleifera</i> Seeds as Hybrid Coagulant for Turbidity and Ammonia Removal from Aquaculture Wastewater

The rapid development of the aquaculture industry has contributed to the high amount of nutrients in wastewater that subsequently led to eutrophication and deterioration of water quality. Aquaculture wastewater consists of uneaten fish feed, fecal and other excretion or residue of chemicals used. Thus, this study aimed to evaluate the performance of hybrid coagulants of Moringa oleifera (MO) and copperas for aquaculture wastewater treatment. In this present study, different formulations of MO and copperas were explored in the coagulation treatment of aquaculture wastewater using a jar test experiment. The FTIR and SEM analysis are used to determine the morphology and surface of MO. This study focuses on the effect of coagulant aids formulation, coagulant dosage, the effect of initial pH and coagulation time on turbidity and ammonia removal in the coagulation of aquaculture wastewater. The finding shows that the highest removal of turbidity and ammonia was obtained with the use of 80% MO and 20% copperas at the condition of initial pH of 6 at 20 min of coagulation time, with the highest percentage removal of 66% and 91%, respectively. The coagulation isotherm of hybrid coagulant 80:20 is well described with the Freundlich isotherm model which describes the surface heterogeneity

Poly-ferric sulphate as superior coagulant: A review on preparation methods and properties

Iron-based coagulants are widely used in wastewater treatment due to their high positively charged ion that effectively destabilise colloidal suspension, and thus contribute to the formation of insoluble flocs. Ferric chloride, ferrous sulphate, and poly-ferric sulphate (PFS) are examples of iron-based coagulants that are highly available, and are beneficial in producing denser flocs, thereby improving settling characteristics. This work aims to review the preparation methods of PFS and critically discuss the influence of these methods on the PFS properties and performance as a chemical coagulant for water and wastewater treatment. In polymeric form, PFS is one of the pre-hydrolysing metallic salts with the chemical formula [Fe2(OH)n(SO4)3−n/2]m (where, n  10) and has a dark brownish red colour as well as is more viscous and less corrosive. PFS has an amorphous structure with small traces of crystallinity, containing both hydroxyl and sulphate functional groups. It has been applied in many industries including water or wastewater treatment which is also discussed in this study. It has the ability to remove pollutants contained in water or wastewater, such as turbidity, colour, chemical and biological oxygen demand, phosphorus, and others. This study also provides a review on the combination of PFS with other chemical coagulants or flocculants in the coagulation/flocculation process, and also flocs formed after a more stable treatment process