DUGi

Effect of sand size and inlet pressure on sand media filter performance using reclaimed effluents

http://dugi.udg.edu/item/http:@@@@hdl.handle.net@@10256@@28673

Sand media filters are specially recommended for preventing emitter clogging when irrigation water with high pollutant load is used in micro irrigation. The objective of this work was to assess those operational conditions related to media size and filter inlet pressure that could yield to a better emitter protection when wastewaters are used. So, an experiment was carried out in a micro irrigation system that had a sand media filter for filtering a reclaimed effluent. Two sand effective diameters (0.41 and 0.63 mm) and three filter inlet pressures (200, 300 and 400 kPa) were tested. Filtered volume, pressure loss across the filter, inlet pH, temperature, turbidity and electrical conductivity and outlet turbidity data were collected every minute in a supervisory control and data acquisition system. Volume used for filter backwashing was also recorded after each filtration cycle. As the reclaimed effluent was supplied by a wastewater treatment plant, there were some variations in its quality across the experiment. Greater sand size significantly (P<0.05) reduced filtered volume and turbidity removal. On the other hand, 300 kPa filter inlet pressure yielded the greatest filtered volume and the lowest backwashing water consumption. Turbidity removal was significantly higher (P<0.05) for both 300 and 400 kPa than for 200 kPa. Results suggest that sand media filter performance is optimised using sand media with an effective size of 0.41 mm and an inlet pressure of 300 kPa

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Wageningen University and Research