Water treatment/ CALCULATOR
Estimate empty-bed contact time and hydraulic surface loading for a cylindrical media vessel.
FROM ESTIMATE TO ACTION
Enter the occupied media volume in litres, the treatment flow through this vessel in L/min and the internal diameter across the bed in millimetres. Do not substitute the vessel’s total capacity, outside diameter or backwash flow. The model assumes a cylindrical bed with uniform flow and no bypass or channeling.
With 50 L of media, 10 L/min and a 300 mm diameter, EBCT is 5 min and surface loading is about 8.49 m/h. At 20 L/min, EBCT falls to 2.5 min while loading doubles to about 16.98 m/h. Doubling media volume at the same flow and diameter doubles EBCT but leaves surface loading unchanged.
Compare both outputs with the manufacturer’s data for the exact media, water conditions and treatment objective. The example is not a universal minimum contact time or an allowable loading rate. EBCT alone does not confirm water-treatment performance. This calculation does not check pressure loss, backwash capacity or actual flow distribution.