ABSTRACT
This work deals with certain factors influencing, the capacity of water treatment plants operating within a network. The common characteristic of these factors is that they cause problems to water supply, resulting to unexpected fluctuations in volumetric water flow which is the main determinant for estimating optimal capacity of a water treatment plant. This capacity is the result of tradeoff between conflict cost variables (i) representing depreciation of capital invested, expenses for operation, water losses during transportation and storing, in-plant water purification, transportation expenses, differential scale economies, and (ii) depended on (the explanatory/independent variables of) level of investment, maintenance level, purification degree, purification capacity. Fault tree analysis (FTA) in its fuzzy version (to count for uncertainty has been implemented to investigate the occurrences causing the top event “high purification cost for achieving acceptable water quality from a PFR-based biological system” used as a case example. Although this top-event is closely related to a specific mode of biological treatment, it can be replaced by another type of secondary wastewater biological processing with only a slight modification of certain intermediate events while the whole framework keeps its validity. The network providing water to the greater area of Athens is also presented in brief and the nodes/subsystems, where FTA might be applied to increase supply reliability, are checked.
