Suspended solids from baitfish pond effluents in drainage ditches

Effluents from aquaculture facilities vary between species and among production systems. Drainage ditches commonly convey effluents from central Arkansas baitfish ponds. Ditches could potentially reduce suspended solids prior to effluent release into receiving streams through settling. We characterized suspended solids in effluents from baitfish ponds and evaluated changes in suspended solids in drainage ditches. We also characterized drainage ditches based on width, depth, slope, and percent vegetation cover. Average (+/- SD) total suspended solids (TSS) at the point of discharge was 52 (+/- 41) mg/L, while volatile suspended solids (VSS) averaged 22 ( 23) mg/L. Screening effluents did little to alter their composition. Approximately 76% of TSS were less than 5 mum. There were no significant changes in effluent solids along drainage ditches 100 m from the point of discharge and no significant correlations between ditch characteristics and changes in either TSS or VSS. Existing ditches are quite variable and are not necessarily effective in removing solids present in baitfish effluents. Screening and use of ditches as settling basins seem impractical for effluent treatment given the characteristics of solids in baitfish effluents.