What sequence is correct for filtration processes from coarsest to finest?

The correct sequence for filtration processes from coarsest to finest is gravity filters, pressurized filters, tangential flow filters.

Gravity filters are the first stage in this hierarchy. They utilize the force of gravity to move water through the filter media, which typically consists of larger particles and sand. This makes gravity filters effective at removing larger solids and debris, laying the groundwork for more advanced filtration methods.

Next in this sequence are pressurized filters. These filters use mechanical pressure to force water through filter media that can capture smaller particles than gravity filters. They are designed for a higher flow rate and can remove finer particulates, thus enhancing the overall quality of the treated water.

Finally, tangential flow filters represent the finest filtration. These operate by allowing water to flow parallel to the filter medium, which not only provides efficient filtration of very small particles but also helps in the reduction of fouling. Tangential flow filtration can filter out very small microorganisms and dissolved substances, achieving a much higher level of purification.

This progression from gravity to pressurized to tangential flow filters illustrates an increase in filtration capability, where each successive filtration method targets smaller and more challenging contaminants effectively.