ÐBiological treatment of a piggery wastewater for organic carbon and nitrogen removal in a combined anaerobic±aerobic system was investigated using two laboratory-scale sequencing batch reactors. The cycle length was 24 h. In the anaerobic reactor, fed with raw wastewater and recycling from the aerobic reactor, denitri®cation followed by anaerobic digestion of organic carbon was observed. In th...

The Relative Gain Array (RGA) provides a quantitative comparison of interactions between control loops. It shows steady state interactions between control loops. The thermodynamic concept of exergy can be used to analyse a process in terms of its efficiency. The Relative Exergy Array (REA) that measures both the relative exergetic efficiency and controllability of a process has been proposed (2...

This work addresses the problem of optimizing completely batch water-using network with multiple contaminants where the flow change caused by mass transfer is taken into consideration for the first time. A mathematical technique for optimizing water-using network is proposed based on source-tank-sink superstructure. The task is to obtain the freshwater usage, recycle assignments among water-usi...

Plant-wide control system design for economically optimum operation of a recycle process with side reaction is studied. The process consists of a liquid phase CSTR followed by two simple distillation columns. The exothermic irreversible reactions A + B → C (main reaction) and C + B → D (side reaction) occur in the CSTR. The reactor effluent is distilled in the recycle column to recycle the ligh...

Fe(3)O(4)@Fe(OH)(3) composite microspheres are highly active, environmentally friendly and easy to recycle catalysts for aldol reactions, which are catalyzed by a solid-liquid interfacial hydrogen bond catalyst at room temperature.

Presented in this paper is a graphical technique for freshwater and wastewater minimisation in completely batch operations. Water minimisation is achieved through the exploitation of inter- and intra-process water reuse and recycle opportunities. In the context of this paper, a completely batch operation is one in which water reuse or recycle can only be effected either at the start or the end ...

The systematic generation of process alternatives for multicomponent heterogeneous or homogeneous distillation systems is described. Alternatives based on distillation and decanting alone must generally be expanded by mixing and occasionally by recycling to provide highpurity products. For azeotropic mixtures, systematic considerations of recycles further expand those alternatives to meet the a...

In order to avoid carbon dioxide (CO2) built up in the atmosphere, the major source of global warming, CO2 capture must be applied to large point sources including natural gas processing. Membrane process, a relatively new technology among other available techniques, can be used for the purpose of CO2 capture from natural gas. Over the decades, the membrane performance has been described by dif...