Requirements for integrated wastewater models - driven by receiving water objectives

The design of efficient technical measures for the abatement of water pollution requires that wastewater discharge regulations are driven by receiving water objectives. However, such integrated water quality management is only possible when the impact to the aquatic ecosystem can be predicted quantitatively by means of integrated wastewater models. Typically, only a few types of wastewater discharge impacts are relevant for the state of the receiving water and, consequently, the structure of the model can be kept relatively simple when focusing on one of these impacts. The procedure of problem-oriented model selection is illustrated for three typical examples of acute water pollution, that is toxicity from un-ionized ammonia, hygienic hazard from pathogenic micro-organisms and oxygen depletion.