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Electrical capacitance tomography (ECT) is widely used in research for different applications, e.g. in the petroleum, pharmaceutical and power industries, due to its nonintrusive and noninvasive features and low cost. So far, ECT has been successfully used with regular structures, such as circular and square shapes. However, in some cases, the measurement electrodes cannot be mounted directly on an irregular structure, high temperature objects or corrosive objects. In this work, a method is proposed for ECT to be used with an irregular structure, by filling the gap between the irregular structure and a regular ECT sensor wall. Accordingly, a split matrix method is proposed for image reconstruction. The characteristics of sensitivity maps with the filling method and different structures are investigated. To calculate sensitivity maps, two methods are used: the perturbation method and the potential method, and their effects on image quality are compared. The results show that there is no obvious difference between these two methods for imaging construction, but the potential method is more efficient than the perturbation method. Among different shapes, an image of a triangular object has a large deformation due to its sharp angle and hence the filling method is not suitable for imaging a triangular object. The split matrix method modified by relaxation factors is suitable for irregular structures in general and can generate satisfactory images. A hardware system based on an impedance analyser and a software package have been developed and used to validate the proposed methods. The experimental results show that the proposed method is promising for imaging two-phase flows in irregular structures.

Due to the residues of metoprolol (MET) in black wastewater, recovering phosphate as struvite (MgNH4PO4 · 6H2O) from black wastewater may pose threats to the utilization of struvite in the agricultural planting and human health. In this study, the adsorption and co-precipitation experiments of MET in the formation of struvite from synthetic black wastewater will be performed and some factors like initial MET concentration, pH values, temperatures were investigated. Results revealed that the adsorption process can be divided into rapid adsorption, fluctuation stage and steady stage, and the maximum MET adsorption quantity was 0.05029mg/g under 80ppb, 20 °C. Chemical adsorption and pseudo second-order kinetics were evident at the low concentration level. Neither Langmuir nor Freundlich isotherms fitted for the adsorption. The presence of Mg[H2O]6 2+ (Hexahydrate and magnesium ions) interfered with MET adsorption through recombining with MET, which was also determined by pH variation. The existence of MET in black wastewater would not obstruct the formation of struvite in alkaline condition generally and serious terrible influences would not be generated when using struvite as fertilizer. A vast majority of MET will stay in the solution after 3 hours’ reaction.