Variable operating costs of wastewater treatment plants

In this paper, variable operation of the plant is studied through a model previously developed for simulating steady-states and optimising the total design cost of a treatment plant. In particular, various possible designs of a plant are considered; for each of them, a set of steady-state values for the effluent quality level, compatible with the initial design, are simulated and the total variable operating costs are optimised. In this way the dependence of the variable operating costs on both the design and operating effluent quality levels can be analysed.