In order to help solving this kind of problems and to get some advantage from the by-products or from the waste, ecological engineering or ecotechnological systems can be used. They include combined production systems and they involve (Shijun and Jingsong, 1989) a set of treatment operations and processes, the regeneration and the cycling of the residues, wastewater and by-products as part of a semi-artificial ecosystem. Valuable final products are obtained.
The present work simulates the homeostatic mechanisms of an ecosystem in order to adjust the structure and operation of an hypothetical semi-artificial, steady sate balanced ecosystem. However, this system still integrates some conventional and confined engineering techniques.
Constructed wetlands and wastewater advanced treatments, still uncommon in Portugal, are also considered. Besides the design parameters, the wastewater treatment sub-system dynamic modelling is performed, considering several: types of production, flow rates, efficiencies, final concentrations and mass and energy balances, along the year, under different abiotic conditions.