Treatment of Aquaculture Wastewater by Vermireactor for Wastewater Discharge or Reuse

Vermifiltration is an emerging technology with the potential of becoming a reliable technology for treatment of wastewaters from different sources especially in low-resource country like Nigeria. In the present study, performance evaluation of vermireactors (Trials EA and AM) for treatment of aquaculture wastewater was conducted for 67 days using earthworm species; Eudrilus eugeniae (EA) and Alma millsoni (AM). Wastewater was applied at hydraulic loading rate of 3 2 3 0.0085 m /m /h and earthworm density of 7877 earthworms/m was used for the treatments. Effluent characteristics were compared with control (without earthworm). In addition, the characteristics were also compared with Nigerian National Regulations for effluent discharges and reuse of wastewater in aquaculture. The presence of two earthworm species aided the removal of BOD (69-80%), COD (46-60%), 5 ammonia nitrogen (87-93%), nitrate nitrogen (67-81%), total phosphorus (45-65%) and potassium (72-81%) in the treated effluent. The treatment process also increased dissolved oxygen (DO) (48-49%) in the treated effluents. The recorded values in the treatment process were higher than values recorded in the control. All parameters of treated effluent from trials EA and AM were within the guideline limits for discharge and reuse of wastewater in aquaculture except for BOD (concentrations were within the permitted limit for discharge, but slightly above the limit for reuse), total suspended solids and phosphorus concentrations. The results thus showed that the two earthworm species employed in the present study were suitable for treatment of aquaculture wastewater. This treatment method provides a sustainable method for treatment of aquaculture wastewater and should be explored further.