Reclaimed Water Filtration Efficiency and Drip Irrigation Emitter Performance with Different Combinations of Sand and Disc Filters

Filters are the most important components in micro-irrigation systems, in particular for filtering high levels of suspended solids in reclaimed water. An experiment was conducted using reclaimed water to evaluate the removal efficiencies of sand filters with different uniformity coefficients (UCS) and in combination with sand filters with a 130 µm disc filter (120-mesh). The treatment effects on emitter discharge were also investigated in this study. The results showed that the sand filters exhibited removal efficiencies of 11.4–48.0%, increasing to 30.7–80.3% when combined with the disc filter. The sand filter removal efficiency decreased with increase of the media diameter. A linear-plateau relationship was observed between the removal efficiency and UCS. Compared to the control group, the combined filters reduced emitter clogging and significantly prevented a decrease in emitter discharge. It is suggested using the equivalent diameter, dt, to represent the filter medium diameter instead of using the effective diameter, de. The recommended value for the sand filter UCS > 2.0 for a mean total suspended solids (TSS) of 17.5 ± 12.7 mg l−1. Copyright © 2015 John Wiley & Sons, Ltd.