Rotary Drum Filter Effectiveness in Suspended Solids Removal from Trout Farm Discharges - A Case Report

Abstract

Utilization of micro-screen filters for mitigation of aquaculture impacts onreceiving water bodies has been widened in recent years. However, there arelimited practical data on treatment efficiencies of rotary drum filters (RDF) in farmswith high production capacities and flow rates. The present study aimed to assesseffluent suspended solids treatment efficiencies of RDFs with 200 μm mesh size in8 flow-through rainbow trout farms. The average concentrations of totalsuspended solids (TSS) were between 2.6±1.1 mg/L and 6.0±4.3 mg/L in farm outletwaters. The average treatment efficiencies of RDFs for total suspended solids werebetween 18 and 32%, while they were between 28 and 53% for farm-derivedsuspended solids. Treatment efficiency of RDFs did not relate linearly to inlet andoutlet total suspended solids concentrations as well as farm-derived suspendedsolids (FSS) (P>0.05). The results indicate that relatively low TSS concentrationsresulting from rainbow trout aquaculture in flow-through farms can reducetreatment efficiency of RDFs. The study also shows that the average treatmentefficiency of RDFs with a mesh size of 200 μm in removal of FSS may reach up to40%.