OPTIMIZATION PARTICLE SEPARATION FOR BETTER WATER QUALITY IN TREATMENT

The goal of the flocculation, sedimentation, dissolved-air-flotation (DAF) processes are to change the particle size distribution to best suit the subsequent processes. Although several methods exist to evaluate each process, no single universally accepted method has yet to be developed. The purpose of this paper is to present experiences whereby particle counting was used in the diagnosis and optimization of each process. The evaluation is based on particle dynamics, i.e., the change of the number of small and large particles. Some design deficiencies and inappropriate operational conditions in each process have been identified from this method. The effects of changed design in each process have been evaluated by comparing the particle counts at the existing design with particle counts after modification. Because the diagnosis of design may be site-specific, the method presented in this paper will be beneficial in the evaluation of the treatment processes at other water treatment plants leading to low cost, low energy operation.