COMPUTER AIDED PREDICTION OF FILTER UNITS' PERFORMANCE

Abstract

The operation of filtration units is very significant in water treatment plant. Most of the suspended solids are removed by the flocculation and sedimentation steps that normally precede rapid sand filtration. Termination of filter run is achieved when filtrate quality has achieved a certain critical limit and the head loss reaches the preassigned maximum permissible value. Rapid sand filters are cleaned by reversing the flow of water and suspending the bed of sand. The agitation during the backwash is sufficient to remove most of the accumulated solids. This makes it possible for a rapid sand filter to treat large quantities of water for many years while only requiring regular backwashing. The prediction of filtrate concentration and head loss are of great interest. Considerable work by many investigators has led to better understanding of the filtration process and produced useful results for practical application. These approaches are based on mathematical models and recursive algorithms. Hsiung and Cleasby (1968) proposed the prediction of filter performance, based on the probabilistic nature of filtration through granular media. In present study, the potential of predicting the performance of sand filter, based on the probabilistic approach, is evaluated. Software in Visual C++ is also developed to render the model user friendly.