Performance of sand filter with disc and screen filters in irrigation with rainbow trout fish effluent

Abstract

Drip irrigation is the most suitable system for reusing effluents in agriculture, but emitter clogging is still its major drawback. Adequate filtration is needed to prevent emitter clogging, but little information is available about the performance of different filter types when using fish farm effluent. The purpose of this study was to evaluate the performance of three filtration treatments for rainbow trout effluent in drip irrigation systems: (1) sand filter (T1), (2) sand filter followed by a disc filter (T2) and (3) sand filter followed by a screen filter (T3). The treatments were tested with a constant discharge of 14.4 m3 h−1 at two working pressures of 300 and 150 kPa until reaching the backwashing threshold. For each filter, the following were computed: filtered volume per cross-section until reaching the backwashing threshold (VB), filtered volume per cross-section unit and head loss (V10), suspended solids removal efficiency (EF) and filter mass retention (q). T2 at 300 kPa had a significantly (p < 0.01) higher VB, whereas T1 and T3 only showed a VB of 53% and 45% at 300 kPa and 48% and 47% at 150 kPa, respectively, higher than that obtained by T2. The results suggest that using a combination of sand and disc filters at an operation pressure of 300 kPa is the best option when using rainbow trout effluent