In order to perform an integral optimization for operation of a drinking water treatment plant, explicit
objectives for optimization have to be identified and defined for operational control. This paper
discusses what these objectives should be with respect to water quality, environmental impact
and costs. Therefore integral assessments are performed for the drinking water production plant
Weesperkarspel of Waternet (formerly Amsterdam Water Supply). It is concluded that the
objectives for integral optimization of drinking water treatment plants should be water quality and
costs. The management should decide upon the relative weight between water quality and costs
keeping in mind that the greatest threat for drinking water companies in The Netherlands is the use
of bottled water for drinking, when tap water quality cannot be guaranteed for that purpose or
clients do not trust the tap water quality. Therefore, emphasis must be laid on maintaining the high
drinking water quality. The environmental impact should not be an objective for operational
optimization of drinking water treatment plants because the environmental impact is relatively low
and will in general benefit from optimization of cost and from good manufacturing practice, for
instance the use of 100% green energy. Assuming that disinfection and removal of suspended
solids and particles are sufficient, the water quality parameters for integral optimization are SI for
chemical stability, AOC and/or biodegradable DOC and DOC for biological stability and disinfection
byproducts and organic micro-pollutants for toxicity. Since the SI, AOC, DOC and pathogen
concentration are influenced by many processes and influence many processes an integral
approach of these parameters is necessary. Because of the complexity of the relations and effects
on these parameters by changes in the operational control, different control strategies can best be
evaluated by an integral model. Includes 23 references, tables, figures.