No abstract

Water treatment plants are in general robust and designs are based on the performance of individual processes with pre-set boundary conditions. It is assumed that an integral approach of the entire treatment plant can lead to more efficient operation. Taking into account the developments in sensoring, automation and computation, it is a challenge to improve quality and reliability of the treatment plants and to make maximal use of the installed infrastructure, postponing new investments. At Amsterdam Water Supply (AWS), the first steps have been taken to come to an integral dynamic model of the total water treatment plant and the use of this model as an instrument for integral control. The parameters influencing the performance of the water treatment process will be incorporated in an overall model evaluating the goal factors quality (good, constant and reliable), quantity, costs, environmental impact (low residuals level), redundancy and flexibility. For several individual processes at AWS models have already been developed during the last few years, like models for the ozone process, biological activated carbon filtration and pellet softening. For the final calibration and validation pilot reactors are automated and on-line data are collected. Criteria for evaluation are developed to realise an optimal control of the individual processes in interaction with the goal factors of the total treatment process.

No abstract

Routine quality monitoring for fecal indicators after ozonation at the river-lake waterworks Weesperkarspel of Amsterdam Water Supply (AWS) show large variation in inactivation. The influence of the high DOC in the water on the inactivation efficiency was investigated. Results showed a higher inactivation of Clostridium perfringens in the AWS water than in a water with low DOC at the same CT conditions. The contribution of the gas feed chamber to the overall inactivation of C. perfringens was high in the AWS water and was reduced after DOC reduction with GAC. This result may alter the current CT concept of the process. Further research will be focused on the ozone dosage strategy and control related to the required CT for inactivation and the production of by-products.