Application of on-line optical determination technologies for optimizing filter performance

This paper reviews the current developments of on-line optical instruments of water quality determination for drinking water filter system, with some experiments on filter system using three different kind of on-line optical instruments, i.e. a standard regulatory turbidimeter, a laser turbidimeter, and a particle counter. These instruments were used to monitor the filter effluent in an effort to determine if the instruments are complementary or the technologies are better suited for the detection of particle spikes before and after filter. The ultimate results showed that compared to laser turbidimeter and particle counter, the standard regulatory turbidimeter has less sensitive to those particle events. If only the laser turbidimeter detects the event, the composition of particle is most likely sub-micron in nature. If the particle counter alone detects the events, which indicates a non-natural distribution of large particle (> 2 mu m) and may indicate a change in the conditions within the filter or a contamination issue. In all cases, the use of three instruments provided further insight into the particle size of respective events.