An optimal trace zinc biomonitor (Haliotis diversicolor supertexta) control system design in aquacultural ecosystems

The purpose of this paper is to synthesize an optimal trace metal biomonito r control system to efficiently manage aquacultural water quality. A biomon itor organism of gastropod mollusc Haliotis diversicolor supertexta was cho sen to estimate zinc (Zn) bioaccumulation. The bioaccumulation dynamics of Zn by H. diversicolor supertexta from an alga Gracilaria tenuistipitata var . liui and ambient water in aquaculture ponds is developed based on a six-c ompartment pharmacokinetic model. A linear control model based on the dynam ic bioaccumulation model is developed to design an optimal feedback biomoni tor control system. Linear quadratic regulators (LQRs) with output feedback control of a linear-invariant system are assigned for design algorithm and an optimal proportional plus integral (PI) feedback control strategy is sy nthesized. Numerical results from the model implementation show that the op timal selection of tuning parameters and the resulting costs vary with desi red equilibrium state. The designed optimal feedback biomonitor control sys tem, when suitably tuned, gives a satisfactory monitor of molluse Zn bioacc umulation. The biomonitor control system developed accounting for bioaccumu lation dynamics of Zn in the target tissues of molluscs can be used in the future to evaluate the effects of suspended solid removal devices and biofi lters and/or other control scenarios on water quality management in aquacul tural ecosystems. (C) 2000 Elsevier Science Inc. All rights reserved.