Availability of adequate water resources is a fundamental requirement for sustainable development. Because of its very limited amounts of...

When applied to large simulation models, the process of parameter estimation is also called calibration. Calibration of complex non-linear systems, such as activated sludge plants, is often not an easy task. On the one hand, manual calibration of such complex systems is usually time-consuming, and its results are often not reproducible. On the other hand, conventional automatic calibration methods are not always straightforward and often hampered by local minima problems. In this paper a new straightforward and automatic procedure, which is based on the response surface method (RSM) for selecting the best identifiable parameters, is proposed. In RSM, the process response (output) is related to the levels of the input variables in terms of a first- or second-order regression model. Usually, RSM is used to relate measured process output quantities to process conditions. However, in this paper RSM is used for selecting the dominant parameters, by evaluating parameters sensitivity in a predefined region. Good results obtained in calibration of ASM No.1 for N-removal in a full-scale oxidation ditch proved that the proposed procedure is successful and reliable.

Wastewater reuse is an important element of Kuwait’s water management system because fresh water is scarce and seawater desalination is expensive. Kuwait reuses a significant portion of treated ordinary domestic wastewater, mainly in irrigation of fodder crops and landscapes. Greywater usually represents a major part (50–80%) of domestic wastewater. More importantly, greywater can be treated and reused much more easily than ordinary domestic wastewater. Yet, reuse of greywater is not common in Kuwait. This paper describes the current situation of greywater reuse in Kuwait and discusses the potential for greywater reuse in Kuwait.