Based on the theory of inverse eigenvalue problem, a correction of an approximate model is discussed, which can be formulated as N X = X , where X and are given identified modal and eigenvalues matrices, respectively. The solvability conditions for a symmetric skew-Hamiltonian matrix N are established and an explicit expression of the solutions is derived. For any estimated matrix C of the analytical model, the best approximation matrixN to minimize the Frobenius norm of C − N is provided and some numerical results are presented. A perturbation analysis of the solutionN is also performed, which has scarcely appeared in existing literatures.

A 'fan-shape' constructed wetland (CW) system is designed to treat domestic wastewater as well as to provide an aesthetically pleasing and environmentally sensitive landscape with ornamental plants for recreation. The system consists of two-stage subsurface horizontal flow CW cells with dewatered alum sludge cakes as the main substrate to ensure the treatment efficiency. The system is located in a new countryside village in Northwest China. The paper presents the design considerations of the CW together with the surrounding landscape to create an integrated CW (ICW). The study attempts to show how the wastewater infrastructure of CW can be an attractive feature in a community; bringing utility and beauty together, and serving needs for education, recreation and habitat conservation, through integrating engineering and landscape design.

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